CA2207257A1 - Variable displacement compressor - Google Patents
Variable displacement compressorInfo
- Publication number
- CA2207257A1 CA2207257A1 CA 2207257 CA2207257A CA2207257A1 CA 2207257 A1 CA2207257 A1 CA 2207257A1 CA 2207257 CA2207257 CA 2207257 CA 2207257 A CA2207257 A CA 2207257A CA 2207257 A1 CA2207257 A1 CA 2207257A1
- Authority
- CA
- Canada
- Prior art keywords
- compressor
- gas
- cam plate
- chamber
- shutter body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
- F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
- F04B27/14—Control
- F04B27/16—Control of pumps with stationary cylinders
- F04B27/18—Control of pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block
- F04B27/1804—Controlled by crankcase pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
- F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
- F04B27/10—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders
- F04B27/1036—Component parts, details, e.g. sealings, lubrication
- F04B27/1054—Actuating elements
- F04B27/1072—Pivot mechanisms
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/22—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by means of valves
- F04B49/225—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by means of valves with throttling valves or valves varying the pump inlet opening or the outlet opening
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
- Control Of Positive-Displacement Pumps (AREA)
Abstract
An improved variable displacement compressor is disclosed. A compressor has a cam plate that is mounted on a drive shaft for integral rotation therewith. At least one piston is coupled to the cam plate. The cam plate is tiltable between its maximum inclining position and its minimum inclining position with respect to an axis of the drive shaft. The piston reciprocates in a cylinder bore by a stroke based on an inclined angle of the cam plate and compresses gas that is supplied to the cylinder bore from an external gas circuit and discharge the compressed gas to the external gas circuit that is connected to the interior of compressor by way of a gas passage. The shutter body is urged by a first spring and a second spring in opposite directions. The urging force of the first spring is greater than that of the second spring. A shutter body that is biased to disconnect the gas passage from the external gas circuit.
Description
-VARIPiBLE ~ISPLA~EMENT COMPRESSO~
BAC~G~OUND OF THE INVENTION
1. E''II~;IJI~ or T~13 INVE;NTION
The present invention generally ~elates to a variable displacement compressox. More particul~ , the pxesent invention ~ertain~ to a ~aria~le displacement co~pressor that lubrica~es moving parts of the compressor by misted lubricant oil ~bntained in ~e~rigerant gas.
BAC~G~OUND OF THE INVENTION
1. E''II~;IJI~ or T~13 INVE;NTION
The present invention generally ~elates to a variable displacement compressox. More particul~ , the pxesent invention ~ertain~ to a ~aria~le displacement co~pressor that lubrica~es moving parts of the compressor by misted lubricant oil ~bntained in ~e~rigerant gas.
2. ~ESCRIPTION OF ~HE RELATE~ ART
A t~pic~l v~riable di3placement compressor includes a cylinde~ block that consti~ut~ a part of the c~pre~or hou~in~. A crank ehamb~ efi~ed in the cylinder block.
A dischaxge chamber and a ~uction chamber ~re also ~efined ~ in ~ ~OmpreS~O~. A ~h~ugh hol~ is de~ined ~t the center portion of th~ cylind~r blo~k. ~ plurality of cylin~e~
bo~es exten~ th~ou~h the c~linder block and are located about the through ho~e. The cylinder ~o~es are spaced apart at equal intervals. The ~hxou~h hole i~ connected ~o an external refrigerant circuit. Re~rigerant gas in the circuit i~ drawn into the suction chamber via a suc~ion passage and the through hole.
A ~ot~y shaft is rotatably supported i~ the crank cha~ber. A cam plate i~ ~uppo~ted by the xotaxy sha~t in the crank chamber. The inclination of the cam plate i~
va~ied in accordance with the dif~erence between the pressure in the crank chamber and the pre~ure in the cylinder bores. The stroke of each pi~ton i~ va~ie~ ln .
a~cordance with the inclination of the cam plate. When the inclination of the ~am plate i~ increa6ed, the ~isplacement of the compres~ox is increased, ~or~ingly. ~ ~ecreased inclination o~ the plate l~wer~ the ~ompressor'~
displacement.
The ~:omp~eE~or i6 p~vid~cl with a di~charg~ chamber that is conne~ted to the crank cham~er ~y a s~pply pa~age.
A di~placement control val~e i~ located in the supply pas~age. The control valve ~ntrols the flow rate of re~rigerant gas from the discharge chamber to ~he Grank chamber thereby ~ontrolling the pre~sure in ~he cr~nk chamber.
A spool-like shutter is accommodate~ in the throu~h hole in the cylin~er block. The ~hutt~ slides in~5 ~ccor~ance with changes in the inclination of the cam pla~e the lnclination decreases, the 3huttex narrows the passage between ~he su~tion p~ge an~ the suction chamber.
If the cam plate xeaches the ~ini~u~ inclination, the shu~er dlsconnec~s the suc~lon cha~be~ from the sucti~n~0 pa~age.
- The control v~lve increa~es the pressure in the cr~nk ~ham~er for re-inc~easing the inclination cf the ca~ plate.
A~ khe same time, the shutter opens the suction passage thereb~ communica~ing the passage with the suction passage again.
Refrigerant ~o~den~ed in the external re~rige~an~
~i~cuit may ~e li~uefled ~y a change in the ambient ~emperatu~e. ~ f the ~hutter does not completely close the suction p~sage when the compre~sor is not operating, the ~iquefied refrigerant in the circuit may flow into the compxe~sor. The lique~ied ref~i~erant is then mixed with the lubLica~t in the compressor. When operation of the compre~sor is resu~ed, the liquefied refrigerant in the compressor may foam up and quickl~ flows back to the refrigerant clrcuit. Th$s also ~11~V~5 lub~icAnt mixed with the liquefied ~e~~iger~t from the Cvmpr~sBO~ . Thus, lubrication of the compLeSsO~ may ~ecome insufficient.
$1T~MARY OF TH~ lNV~NTION
~ccordingly, it is an o~ectlve of the present in~ention to provide a construction for lubricati~g each moving part in a compr~ o~ wh~3n tho c~mpre~or ~start~
operating fxo~ a ~tationar~ s~ate .
To achieve the foregoing and other objectiv-2s and in ~5 acco~dance with the ~urpose of the present invention, a compressor having a cam plate mounted on a dxive 6haft for in~egral rota~lon t~erewith and a piston cuupled t~ the cnm plat~ i~ provid~d. The cam pla~ tiltabl~ ~tw~Qn it~
maxim~m inclining po~ition and its mini~u~n inclining p~sition wi~h xespect to an axis of the dx-ive shaft. The piston reciprocates in a cylinder bore by a 6~xoke based on an inclined angle o~ the cam plate to Compress gas suppliecl to ~he cylinder bore from an external gas cirC~it and to discha~ge ~he compxe~sed g~s to the ex~e~nal gas circuit.
~he compLessor lncludes a gas pa~sage connecting the ~xto~n~l ga~ ~i~c~i~ to th~ int~rio~ o~ c~mp~e~so~, ~
shut~e~ body for selectively connec~ing an~ disconnecting the gas pa'~sage wi~h the external qas circuit, and ~iasing ~eans for ~iasing the ghutter ~ody to disconnect the gas pa~s~ge w~th the external gas circuit when the compressor i~
-Ln an inoperati~e ~tate.
BRlEF D~;SC~IPTION t:~F THE: DRAWINGS
Pig. L i~3 a cro~ sec~lonal view lllustrating a v~ri~le di~placemen~ comp~e~cor according ~o ~ ~ir~t ~ -t ~f the pre~en~ invention;
Fig. 2 is a cross-sectional ~~iew illustral~ing the compresso~ of Fig. 1 when the inclination of the sw~f;h plate is mi rti -;
Fig. 3 is a cxo~;s ~;ec!tional view illu~tra~ing a compressor acc~rdin~ to a second embodiment of the presen~
inven~ion; and Fig. 4 i~ a cro~ sectional vie~ illustrating a co~p~e~o~ accor~in~ ~o a third embodimen~ of th~ pxesent invention DETAILED ~ESCRIPTION OF THE p~FE~RE~ EMBODIMENTS
A variable displacement compre~60r accor~ing to a first e~bodiment of the pre~ent inv~n~ion ~ill now be descri~ed with ~e~erence t~ Flgs. 1 an~ ~.
A cylinder block 11 constitute~ a part o~ the co~pre~or hou~ing. A front housing 1~ is secured ~o the fron'c end face of ~ eylinder block 11. A rear hc1using 13 is secured to the rear end face o~ the cylinde~ block 11 with a valve pla~e 14 in ~etween. A crank chamb~r 15 is de~ined by 'che inner wall~ c~f the front hou~;ing 1~ and the front end face of the cyli~d~r bl~ck 11.
A rotary shaft 16 is rotatabl~ supported in th~ front housing 12 and the cyl~nder block 11. The fron~ end of the rotary shaft 1~ protrudes f~om the crank chamber 15 and is secured to a pulley 17. ~he pulley 17 is directly ~oupled to an external drive E;ource (a ~~ehic~le en~ine E in this en~bodiment) ~y a belt 18. The c:~ompreE~;or of thls embocliment ts a clutchles~ type v~i~l~ di~pl~e~ent c~mp~en~or having no clutch between the ro~a~y ~haft 16 and the drive source.
~he p~lley 17 is ~upport~d by the f~ont housing 12 with an angular bearing 19. The ang~lar bearing 19 txan~fers thru~t and radial lo~ds that act on ~e pulley 17 to ~he hou~in~
12.
A lip seal 2~ is located be~ween the rotary shaft 16 and the ~ront hou~ 12 for ~ealing the crank chamber lS.
The lip ~eal 20 prevents the pre~sure in ~he c~ank chamber 15 from leaking.
A subs~antiall~ di~k-like ~wash pla~e 22 is s~pported by the rota~y sha~ 16 in the crank ~hamber lS to be slida~le along and tiltable with regpec~ ~o ~he axls o~ the ~haft 16. ~he swa~h plate 2~ i8 provided with a pair of guiding pin~ 23, e~h having a g~id~ ball at its distal end.
A rotor Zl is fixed to the rotary shaft 1~ in the crank ~ha~be~ lS. The rotor 21 rota~es integrally with the xotar~
shaft 16. The rotor 21 ha~ a ~upport arm 24 pxotru~ing toward the ~;wa~;h plate 2~. A pair of guic~e ho~es 25 are formed in the support arm 24~ ~ach guide pin 23 is slidably fitted lnto the corre~ponc~.~ng gulde hole Z5. The ~ooperution of the ~rm 24 ~n~ the guid~ plnG ~3 permit~ th~
~wash plate 2~ to rotate to~ether with the rotary shaft 16.
The cooperation al~o ~uides the tilting of th~ swash plate 2~ and the movement of the swash plate 22 along the axis of ~ 5 .
-the rotaxy ~haft 16. A~ the 8~a~h plate 22 sli~es rearwar~
toward the cylindex block 11, the inclination of the sw~h plate 2Z de~reases.
A fir~t coil spring 85 is located be~ween t~e ro~x 21 and the ~swash plate 22. ~h~ X ir~ apri ng ~5 ~rges th~3 E;wash plate 22 x~s~war~, or in a di~e~ion de~reasing the inclination of the swash plate 2~. The rotor 21 is provided ~ith a pro~ectioll 2 la on its rear end ~ace . The abutment of the ~wash plate 22 agains.t the projection 21a prevent~ the 1~ inclina~ion of the swash plate 2~ beyond the pre~etermined maximum inclination.
~ ~h~tter chan~ber 27 i~ dQ~in~ at thQ cont~r portion of the Gylinder block 11 and extend~ along the axis of the rotary shaft 16. A hollow cylindrical ~hutter 2~ with a close~ end is accom~odated in the ~hutte~ chamber 27. The ~hutte~ 28 slides along ~he axis of the rotary shaft 16.
The shutter ~8 has a large diameter portion 28a and a s~ll diame~er portion 28b. ~ 8econd coil spring 86 is located between a step, which i~i de~fined by the l~rge dinme~ter portion 2Ba and the small diameter po~ion 28b, and a w~ll of the shutter chamber 27. ~he se~ond coil spring ~6 u~ges the ~ shlltte~ ~8 toward the swash plate 2~ . The urging forc~e o~ the fir~;t sprin~ 85 is greater ~han the force of ~he second spring 8 6 .
The rear end o~ the rotary shaft 16 Ls inse~ted in the ~huttGx 2~. A radial b~aring 30 io ~ix~d to th~ inn~ wa~l of the large di~meter po~tion 28a of the shutte~ 30 by a snap ring 31. Thexefore, the ~adial ~earing 30 ~oves with the shutter 28 along the ~xi~ of the xo~ary ~ihaft 16. The rear end of the rotary shaft 16 is ~uppo~te~ ~y the inner CA 02207257 l997-06-06 wall of the ~hutter chambeL 27 with the radial bearing 30 and the shutter 28 in between.
A suction passage 32 is defined at the center portion of the reax housing 13 and the valve pla~e 14. T~e pa~sage 32 is aligned with the RXi~3 o f the rote.~y ~ha~t 16 and i8 c~ nica~d with th~ shuttor ch~ ~ 27. The suction pa~age 32 function~ as a suction p~e6~ure area. A
p~sitioning ~urface 33 is fo~med on the v~lve plate 14 about the inner opening of ~he suction passa~e 32. The reax end of the ~hu~te~ 28 a~uts against ~he posi~ioning 8urface 33.
Abutment of the shutter 28 against the po~itioning su~face 33 prevents ~he shut~er 28 from ~oving further rearward away from the swash pl~e ~. The ~butment ~12~o di~connects the suc~ion pa~age 32 from the shutter chamber 2~.
A thrust bearing 34 is suppor~e~ on the rotary ~haft 16 an~ is located between the ~wash pl~te 22 and the ~hutter 28. Th~ th~t bearing 34 8:Licle8 along the axi~i of the rotary shaft 16 and is constantly retalne~ be~w~en ~he swa~h plate 22 and the sh~tter 2~ by the fc~rce of the 2!~cond spring 86. The thrust be~ing 34 prevents ~he rotation of the ~wash plate 22 from being transmit~ed to the ~hutter Z8.
The swash plate 22 ~oves rearwar~ as its inclina~ion decreases. As it moves rearw~, the swash plate 22 p~shes the shu~ter 28 rearward through the ~hrust bearing 34.
Accc~rdingly, tlle shutter 28 moves ~oward the pc~sitic~nir~g ~urfac~3 3~l againE;t th~ fo~cc~ o~ ~ho .i;~con~ s~p:~ing 86. ~
illustrate~ by a ~ashed line and a continuous line in Figs.
1 and 2, the rear end of the ~hutter ~8 abuts against the positioning surface 33 when ~he xwash plate 22 reache~ the minimum inclinati~n. In thi~ sta~e, the shutter Z8 is located at the close~ position ~ox disconnectin~ the shutter chamber 27 ~rom the suc~ion ~a~sage 32.
A plurality of ~ylin~er bores lla extend ~h~ou~h the cylincler block 11 and a~e located d~ut ~he axl~ of ~he rota~y ~ha~t 16. ~he cylinder b~r~ }~a ~xe spaced up~t a~
equal interval~. A ~inglo--h~.d~3d pi~ton 3S is acconmodated in each cylindex bore lla. A pai~ of semisphe~icaL shoe~ 3fi are fi~ted between each pi~ton 35 and the swash plate 22. A
semispherical portion and ~ flat portion are defined on each ~hoe 36. The ~emi~pherical por~ion slidably contac~s the pi~ton 35 while the ~~at portion slida~l~ contact~ the swash pl~te ~?. The swash plate 22 i~ ro~ated by the rotary ~haft 16 through the rotor 21. The ~t~ting ~ ?nt of the ~wa3h pla~e 22 i~ transmitted to each pis~on 35 th~ou~h the shoes 3G and is conver~ed ~o linear reciprocating movement of each piston 35 in the a~s3ociated cylinder bore lla.
A suction chamber 37 is de~ined in ~he center po~tion of the rear housing ~3. ~he suction chamber 37 is commun~cated wlth ~he ~hut~ex chamber 2 7 via a com~nicntion hole 45. A discharge chambex 38 is defined about the suc~ion chambe~ 37 in the rear housing 13. Suc:ti~n ports 39 ~nd discharge port~ ~0 a~e formed in the valve plate 14.
Each ~u~tio~ port 3g and ~ach discharge por~ 40 correspond to one o~ the cylindex bores lla. Suction valve flaps 41 are forme~ on the valve plate 14 . ~a~h suction valYe flap 41 correspon~s to one of the suctLon por~ 39 ~ischarge valve ~laps 4Z are fc~med ~n the vn~r~ pl~t~ 14. E~ch di~charge v~lve flap 42 co~respond~ to one of the di~cha~ç~e po~ts 40.
A~ each pis~on 3S moves from the top dead center to the bottom deacl c~nter in t.he ~sociated c~linder bore lla, refrigerant gas in the suction cham~er 37 is ~awn into each cylinder bore lla through ~he associated suction port 39 while causing the ~s~ociat~d suction valve flap 41 to flex to an open position. As each piston 35 moves from the bo~om dea~ cent~r to the top dead center ln the as~ociated cyl i n~r bore llo.~ refrig~x~nt ga~ i~ aompxQ6~;~d in th~
cylinde~ ho~e ~la and di~charged to the discharge cha~ber 38 through ~he a~ociated di~charge port 4~ while causing the associ~ed di~charge valve flap 42 to flex ~o an open position. Retainers 43 are ~ormed on the valve plate 14.
Each retainer 43 corresponds to one of the ~i~charge ~alve ~lap~ 42. The openin~ amount o~ each diLcharge val~e flap 42 is ~e~ined by ~ontac~ between the valve flap 42 and the ~;~oci~ted ;retainer 43.
A thrust bearing 44 is located ~etween the f~on~
housing 12 and the rotor 21. The thrust bearin~ 44 carries the reactive force ~f ga~ compres~ion acting on the rotor ~1 through the pistons 35 and the swa~ pla~e 22.
~0 A pxessure release passage 46 i6 defined at the cent~r portion of the rotary shaft 16. The pressure relea$é
pa~age 46 has ~n inlet 4~a, whi~h open~ to the crank chamber 15 in the vicinity of the lip ~eal 20, and an ou~let 46b, which opens to the interior of ~he ~hutter 28. A
pres~ure release hole 47 is formed in the peripheral wall near the rear end of the shu~ter 2~ ~he hole 47 comm~nic~oa th~ interior of the sh~t~er 28 with th~ ah~tte~
chamber 27.
A supply pa~age i8 i~ defined in the rear housing 13, the valve plate 14 and the cylinder block 11 fo~
g -communicating the dis~ha~ chambe~ 38 with the crank cha~e~ 15. A displacement control valve 49 is accommodated in ~he rear housing 13 ~i~way in the supply passage 4~. A
pressu~e introduction pas~age SQ is defined in the ~edx S housing 13 for com~unicating the control valve 49 with the ~uction pa~sage 32. Thus, the s~lction pre~3ure :P6 i~;
communicated with the ~nt~ol valve 49.
An outlet port ~1 is fo~med in the cylinder block 11 and iS ~o~municated with the discharge chamber 38. ~he outlet por~ Sl is connected to the ~uction pas~age 32 by an external refrigerant circuit 52. The refrigerant circui~ 52 includes a conden~er 53, an e~pan~on val~e 5~ and an evaporator 55. A temperature sensor 5~ is loc~ted in the vi~inity o~ the evapo~ator 5S. The temperat~re sens~r 56 detects the temperature of the evaporator 55 and issues ~ignals relating ~o the detec~ed t~mperature to a computer 57. ~he computex 57 is connected to v~i~u~ ~evices incl~ding a temperature adjuster 58, a passenger c~mpa~ment temperature ~ensor Sg, an ai~ conditioner ~arting switch 60 ~0 and an engi~e speed ~en~o~ ~1. A passenger sets a desirable compartment te~per~tu~e ~y the temperatuxe adjust~r 58.
- The computer 57 computes a cu~en~ value for the control valve 4~ ~ased on various condition~ including, for éxa~ple, a ~arget ~empexatu~e ~et ~y the temperature ZS adju3tex 58, the temperatur~ de~ected b~ the te~perature sen~or 56 r ~he pas~enger ~ompartment temperature ~e~ected by the tempera~ure serlsox 59, the engine speed detected by the engine ~peed ~en~or 61 an~ an ON~OFF ~ignal from th~
starting ~witch G0. The computer 57 transmits the computed ~u~ent valu~ to a driver 62 The ~river 62 ~end~ a current having the value ~ran~mitted from the computer 57 to ~ ~oil 63 of a ~olenoid 65 in the valve 4~. The ~oil 63 an~ the solenoid 65 will be desc~ibe~ later. Th~ con~itions for determining the current value ~or the valve 49 may includes dat~ other than those listed above, ior ex~mple, ~he data S may incl~de ~he temperature out6ide o~ ~he ~hicle..
The cont~ol ~l~e 49 i~cl~den a ho~sing 64 and th~
solenoid 6S, which a~e secured to each other. A valve chamber ~6 is defined bet~een the housing 64 and the ~lenoi~ 65. The valve cha~be~ 66 is connected to the ~ischa~ge chamber 38 by the supply pa~sage 48. A valve b~dy 67 i~ arranged in the valve ¢ham~er 66. The area about the opening of the valve hole ~8 function~ as a valve ~eat, agains~ which a top end o~ the valve body ~7 abut~i. A c~i}.
sprirlg 69 extends be~ween the valve ~ody 67 and a w~ll of th~ valv~ cha~b~r 66.
A pressure sensing chamber 71 i8 defined at the upper portion of the housin~ ~4. The chaInber 71 is provided wi~h a bellows 73 and is conne~ted ~o the ~uction passage 32 by the p~es~u~e in~roduction passage 50. Suc~lon pres~u~e PS
in the suction pasGage 3~ i~ intro~uced to the chamber 71 via th~ pa6~ago 50 an~ i~ d~t~ct~d by th~ bollows 73. The bellows 73 i~ connec~ed to the valve body 67 by a first rod 75. ~he v~lve hol~ 68 i~ co~nected to the crank chamber 1 by the ~upply passage 48.
An ac:co~unoda~lng hole 77 i~3 defined in the ~enter por~ion o~ the ~olenoid G5. A fixed 3teel core 78 iG ~itt in ~ho upp~r portion ~f the hole 77. A plunger chamber 79 is de~ined by the fixed core 78 and inner walls o~ the hole 77 at the lower por~ion o~ ~he h~le 77. A plunger 80 is slidably accommcsdated in the chamber 7Y. A coil ~:pring 81 extends between the plunge~ 8~ and the bottom of the hole 77. ~he ur~ing forc:e of the 5pring 81 is ~imaller than that of ~he coil ~iprin~ ~q. The ~:p~ing 6g u~ge~3 the valve body fi7 do~nward, while the sprin~ 81 urges the plunge~ 80 5 upward. T~i~ allow~ the lower end of the second rod 83 to constantly cont~c~ the plunger 80. In other ~o~d~, the val~re b~dy 67 ~ove~ integr~lly with the pl~nger 80 wi~h tho secon~ rod 83 in between.
A cylindrical c:oil 63 is wound about the core 78 anc~
the plunger 80. The driver 62 supplies coil 63 with a current; ll~ving a value computed by the computeI~ 57.
When thl3 ~wi~ch ~0 i~: ~urn~d on, i~ th~ compartment temperature detected by the temperature sensor 59 is e~ual to or greater ~ha~ ~ taXget temperature, the Computer 57 comm~nds the d~ive~ ~2 to excite solenoid 6~. A current i~
~upplied to the ~oil 63, accordingly. This generates a ~agnetic attractive force betw~en ~he core 78 and the plunger 80. The attractive force urges the valve ~ody 67 in a di~ecti~n clo5ing the valve hole 68. On the other h~nd, ~he length of the bellow~ 73 changes in accordance with the suction pres~ure Ps in the suction pa~ e 3~, which is introduced to the pressu~e sen~ing chamber ?1 via the pas~;ag~ 50. The ~hange~ in the length of the bellows 73 are trans~itted to the valve bo~ 67. The higher t~e suction pre~;~u~e P~: i8~ the ~horter the bellows 73 }:~ecolne~. As the ~ellows 73 beco~es sho~te~, t~e ~ellows 73 pulls the valve ):oc~ G7 in ~ ~i~c~c~cion c~ ~ing the vcllve hole 6~.
The opening area be~ween the valve body 67 and the valve hole 68 i~ determined hy the e~uilibrium of forces a~ting on the valve body 67. Specifically, the opening area -CA 02207257 l997-06-06 i8 d~at~rmined b~ the equilibrium po~ n of the body h7, which i~ affected b~ the force o~ the ~vlenoid 65 transmi~ted through the second rod 83, ~he fol~ce o~ the bellow~ 73 and ~he force o~ the sp~ing ~g.
~;u~pose the cooling load is great, the l:em~?era~:u~e in the vehiele c~mp~t~ent detected by th~ ~60r 59 i~
si~nificantly higher than a target te~pe~ature set by the ~emperature a~juster 58 and the suction pre~sure P~ is high.
The computer 57 sets a higher target current value when the difference be~7~n the detected temperatu~e and the tar~et temperature is gre~t. This inCreAseS the magnitude of the attractive force ~etween the c~re 78 and the plunger ~0 the~eby inCrea8in~ the resultant rOr~e urglng ~he val.ve body ~7 in a dire~tion closing the ~a~ve hole 68. Thi~ Iower~
th~ valuQ of pr~s~ure Ps required for opening of the ~al~re hole ~8. Increa~ing the value of the current t~ ~he ~alve 49 cau~es the valve 4g to maintain a lower suction pre~sure P~
A ~maller opening area between the valve bod~ 67 and the valv~ hole 68 decrea~es ~he xe~rigeran~ ga~ f ~ ow fro~
the di~h~rg~ chamb~r 38 to the c~ank chamber 15 via the pas~age 48. The re~rige~nt ~as in the crank chamber 15 flows into ~he suc~ion chamber 37 vi~ the pressure ~elease passa~e 4~ and the pressure relea~e hole 47. This lowers 25 the pressure Pc in the c~ank chambe~ 15. ~urther, when the cooling load i~ great, ~he suction pressure Ps is hi~h.
~ccordingly, the pre~5ure in each cylin~er bore lla i~ hi~h.
The~efore, the di~fe~ence between th~ pr~G~u~ Rc ;n th~
crank chamber 15 an~ the pressure in ~ach cylin~er lla 1~
s~all. This incxea~e~ the inclina~ion of ~he swash plate 22, thereby allowing the compre~;or to c~perate at a large , dis~lacemen~.
When the valve hcle 68 in the val~e 4Y i~ completely close~ b~ the valve body ~7, the supply pa~sage 48 is clo~ed. Thi~ stops the ~iu~ply of the hi~hly pressurlzed refriger~nt ~ab i~ th~ ~i~ch~rge ch~mber 38 ~o ~.he ~ank ch~mb~ ;. q'h-r~i~or~ ch~ prns~urc~ Pc in ~he crank chaTnber 15 becomes substantially the ~ame aç the low pressure Ps in the SuCtion chamber 37. The in~lination of the swa~h plate 22 thu~ becomes maximu~ a~ shown in Fi~. 1, and ~he compre~or op~rates at the ~y~ m displace~ent. The abutment of th~ swash plate 2~ and the p~o}ection ~la of the xotor Zl prevent~ the swash pla~e 22 from inclining ~eyond th~ ~ _~e~ermined ~Xi~ i~clinc~tion.
Suppo~e the co~ling load is S~dll~ the difference between the compartment temperature detec~ed by the senso~
5g and the targe~ temperature ~et by the temper~tu~e adjuster 58 is s~all and ~he suction pressure Ps is l~w.
The computer 57 command~ the d~ive~ 62 to decrease the cu~rent value t~ the c~il 63 ~f the ~lve 49 for n ~m~ller difference between the de~ected tempe~ature and the tar~et temperature. This decreases the magnitude of the attractive force between the core 78 and the plungex BO the~eby ~ecreasing the resultant force ur~ing the valve body 67 in a direction clo~ing the valve ho~e 68. Thi~ increa~e~ the value of the pressure PB tha~ will oper~ the valve hole 68.
Decrea~ing the value o~ the current to the valve 49 cau~e~
the ~nl~e 49 to mnintnin n hiyher ~tion p~es~e P~-A lars~er opening area between the valve body 6? and thevalve h~le 68 incxea~e~ the refrigerant gas ~low from the 30 dis~ha~ge chamber 38 to the crank chamber 1~. This inc~eases the pressure P~ in the c~ank chambel 15. Furthe~, ' when the cooling lo~d is smal~, the ~uction pre~sure Ps i~
low and the pres~re in each cylin~er bo~e lla is low Therefore, the difference between the pressure P~ in the crank chamber 15 and the ~ressure in each cylinde~ lla is gLeat. This decre~e~ the incllnation or ~he ~ash plate 22 thereby all~winy the cc..~l~8~r to oper~te at a ~mall di6placement.
A~ cooling load app~oache~ zero, the temperat~e of the evapo~ator 55 in ~he refrigerant circuit 52 drops to a f~o~t formin~ temperature. When the tempera~uxe ~ensor 56 detects.
a temperature that i8 lower than the frost formin~
temperatuxer the computer S7 ~ -nd~ the ~iver 62 t~
de-excite the ~olenoid 65. The driver 62 stops sendi~g cur~ent to the coil 63, accordingly. This eliminate~ ~he ~agnetic attractive force between the ~ore 78 and the plunger 80. The valve bo~y ~7 is then moved by the fo~ce of the ~pxing 69 again~t the force of ~he ~p~ing 81 transmitted by the plunger 8~ and ~he second rod 83. The valve ~ody 67 is moved in a direction opening the valve hole 68. Thi~
maximizes the opening a~e~ between the valve body ~7 a~d the valvo hol~ 6~. Acco~ding~y, th~ gas flow from the ~ischarge cha~ber 38 to the crank ~h~mbe~ 15 i~ inc~ea~ed. This fu~the~ raises the pressure Pc in the cx~nk ch~eL lS
thereb~ minimizing the inclination ~ the swash plate 22.
The com~re~or thus opera~es at the mini~u~ displacement.
When the ~wltcl~ 60 is turned ~ff ~ the c~mp~te~ 57 c ~ tho dri-~or 62 to t3q c~Y~ e the çtolenoid 65. Thi~
also ~inimizex the inclination o~ the swash plate 22.
30 As described above, when ~he value of ~he current to the coil 63 is increased, the val~e hody 67 o~ the valve 4 allows the opening ~ea of the valve hole 68 to ~e controlled by a lower ~uction pressure Ps. When the value of ~he cur~ent to ~he coil 63 i~ decrea~e~, on the othe~
hand, the valve body 67 allows the opening area o~ ~he valve hole 6~ to be controlled by a higher suc~ion ~re~ure P~.
The co~pre~or control~P the inclination o~ th~ ~a~h plat~
~2 to ad~ust its di~p~ace~ent thereb~ maintaining a target 8uCtLOn pressU~ce pF~ . ~hat is, the valve 49 change~; the target value of ~he su~tion pressure Ps in accordance ~ith the v~lue of the current supplied ther~to. Al~, the ~alve 4g ~ause~ the compr~ssor to operate at the minimum di~pla~emen~ ~or an~ given suction pressure Ps. ~
compressor equipped with ~he c~ntrol valve 49 v~xle~ the cooling ability of the air conditione~.
The shutt~ 28 slides in accordance with the tilting motion of the ~wa~h pla~e 22. As the inclination of the ~wa~h plate ~2 decreases, the shutter 28 gxa~ually reduces the cross-sectional area of ~he pas~age between the suction passage 32 and the s~ction chamber 37. ~his ~rad~ally reduces the amount of refrigerant gas that ente~s the ~QU~tiOn ch~n~D~r 37 from th~ ~tion pas~a~e 32. The amo~nt of ~efrigerant gas that is d~awn into the cylinder bores lla fxo~ the s~ction ~hamber 37 gradually decrea~e~, accordingly. As a re~:ult, the displacement of the compres~or gradually decreases. This graduall~ lowers the discha~ge p~essu~e ~d of the compressor. The load torque of the ~:ompxessox thu~ gradual:Ly decrea~;es. In t}~5.s manner, the lo~d torq~e for oper~tin~ the com~e~oor doe6 no~ ch~ngc dramatically in a short time when the displacement dec~ea~es ~rom the rQxi~lm to the mini~um. The shock ~hat accompanies load torq~le ~luctuations is therefore le~ened.
.
When the inclination of ~he swash plate Z2 is m-nimum, the shutter 2B abuts against the positionin~ surface 33.
The abutment of the shutter 28 agains~ the po~itioning ~rface 33 prev~nt~ the inclination of the swash plate 2Z
S fxom being sma~le~ than the pre~e~ermined minimum inclination. The abutment ~1160 clisconr~ects ~che suc~lon pa~ge 32 from the suction chAmber 37. Thi6 Gtop~ tho ga~
f}ow from the refrigerant circuit 52 to the ~uction chamber 37 thereby stoppin~ ~he circulation of ref~igerant g~
between the circuit 52 an~ the compre~or.
The n~ini I inclination of the swash plate ~2 is slightly larger than zero degrees. Zero degrees refer~ to the angle o~ ~he swa6h plate~ inclin~ion when it perpendicular to the axis of t~e rotary shaft 1~.
Therefore, even if the inclination of the swash plate 22 is minimum, refrigerant gas in the cylinder bores lla is discharge~ to the discharge chamber 38 and the compressor opexate~ at the minimum displace~en~. The refrigerant gas discharged to ~he discha~ge chamber 38 from ~he ~ylinder ~Q boxes lla is drawn into the crank chamber 15 ~hrough the supply p~ e 4~. The refrigerant ga~ in the c~ank cham~er 15 i~ drawn back into the cylin~r ~ores 11~ th~ough the pre~ur~ release passage 4~, a pres~ure release hole 47 and the suction chamber 37. That is, when ~he inclination of the swash plate 22 is minilnum~ refrigerant ga~ circulates within the compressor traveling through the discharge chambex 38, the supply passage 48, the crank ch~mbe~ lS, the pres~uLe ~el~ase passage 4~, ~che pre~;~ure rele~t;e hole 47 r thc ~uction ch~mber 37 ~n~ the c~linder bor~ lla. Thi~
30 circulation o~ refri~exant ga~ allowx ~he lubri~ant oil contained in the ga~ to lub~icate the moving parts o f the compress~r.
If th~3 ~wi~ch 60 iç: tu~ned cln and the inclination of the ~wa~;h Plate 22 i6 minimum, an increa~;e in the compartment temperatu~ increase~ the cooling load. Thi~
causes the comp~rtment tempe~ature detected by the sen~r ~9 to be highe~ than a targe~ te~perature ~et by the te~pe~a~ure adjuster 58. ~he compute~ 57 command6 ~he driver 6Z to excite ~he solenoid 65 in acco~dance with th~
detect~d tempera~u~e increase. ~xcitin~ the solenoid 65 close~ the supply passage 48. Thi~3 stop~; the flow of refrigerant ga~ fro~ the discharge chamber 38 into the crank chamber 15. ~he ref~iqer~n~ gas in the crank chamber 15 flow~ into the suction cham~e~ 37 via the pxe~ure release pass~ge 46. This gradually lowers the pressure Pc in the crank chamber 15 there~y moving the swash plate ~2 from the ;n--unl inclination to the maximum inclination.
As the swash plate~s Lnclination inc~e~ses, the ~OLC~
of the second fip~ing 8~ gradually pushe~ the shutter 28 away from the positioning surface 33. Thi~ gra~ually increase~
the amount of refrigerant ga~ flow from ~he suction pas~age 32 into the ~u~tion cha~er 37. Therefore, the amo~t of refrigerant gas drawn into ~he cy}indeL bo~es lla from the ~uc~ion ch~b~r 37 grQ~ually incr~a~e~ ~hi~ ~llow~ the di~plac0ment of tho comprossor to gradually in~ease. Thus, the discharge pressure Pd o~ the compxe~or grad~ally increases and the torque needed for ope~atin~ the compressor al~o gradually increases accordin~l~. In this manne~, the load torque of the compressor doe~ not change ~ramatically in a ~;hort tilne when the displacement increases from the minimum to ~he m~Y-tm~ The E;hock tnat accompanle~ load toxque fluctuation~ i~; therefore le~e~ed If ~che engine E is stopped, the cc~mpre~:o~ is al80 ~topped (that is, the ro~ation of th~ swa~h p~ate 22 is stopped). Also, the supply of cu~ren~ to the ~oil 63 in the valve 49 i~ stopped. This de-excit~s ~he 601enoid 65 thereby opening the supply pass~ge 48. The inclination of the swash plate 22 is thus minimum. I~ the nonoperatlonal state o~ ~he compressor c~ntinues, the pr~sure~ in the cha~ber~ of th~ ~Omp~O~O~ b~como ~ualiz~d and th~ swash pla~e 22 i~ kept at the minimum inclination by the iorce ~f fir6~ spri~q 85. ~he~efo~e, when the compres~or is not ~pe~ating, the interior o~ the comp~e~sor is completely disconnec~ed fxom the ~ef~igerant circuit 52. Thu~, even i~
the nonope~ationa~ state of the compre~ c~ntinue~ over a relatively long perio~ of time, llquefied refrigerant in the c~rcuit 5z i~ prevente~ from ente~ing ~he compres~or.
A~ descri~ed in the background ~ection, wh~n the compres~or i8 re-~:tarted by the engine E, a small ~unount o~
1 iquef ied ~e~rigerant may exist in the comp~es~or . Fo~ming of the li~ue~ied refrigerant is prevented ~in~e liquefled refrige~ant i~ prevented from entering the compressox.
T~Us, lubricant ~;tc>red in the compreg50r i~; preven~ed ~rom being mixed with ~h~ liquefied refrigerant and from being remo~ed to the refrigerant circui~ 52. Lubrication of the ~ov~ng parts in the compres~o~ i~ i~proved, accordingl~.
Fig. 3 shows a second e~bodiment o~ the present inven~ion. In this embodiment, an end of the guide hole Z5 . in the ar~ 21 i~ closed by a wall ~2. The hole 25 hax a U-:~h~-pcd c:~O~ e~:tion. A ~p~iny 91 ex~nd~ t~e~ the wall 92 and the ~uide pin ~3. The sprin~ 91 u~es the swash plate 22 in a direction decreasing the inclination of the plate 22. The urging ~orce of the spring 91 is g~e~ter than that of the ~pring 86, which open~ the ~hutter 28.
If the comp;~e~:sor is not operating and the pre~3sures in th~ chalnbers of the compressor a~e equalized, the swa~h plate 22 re~ches the minimum in~lination. Thi~ ~auses the shutter to close the suc::tion pa~ age 32. In thig State~
liquefied refrigerant in the refrige~ant circuit 52 is prevented from ente~ing ~he co~pxessor. There~ore, when th~
co~presyo~ 5~rt~ operQting ~in, lubricant in th~
compressOr is n~ ~emoved ~o the circuit S2 by foaming of the liquefied refrigerant.
If the pressure in the crank cham~er lS is lowered, highly pressurize~ heated ~as from the discharge cham~er 38 is drawn into the crank cham~ex 15 via ~he pa~sage 48.
Thu~, parts in the crank cha~ber 15 are exposed to the ~eated gas. ~owever, the 6p~ing 91 is loc~te~ in the arm Z4 ~5 having a U-shaped cross-se~ion an~ i~ no~ directLy exposed to ~he gas fi~w. The ~pring 91 is thus not affected by the heated gas flowin~ in the crank chambex 15. Thi~ improves 'the durabil~ty of the spring 91.
A ~hird embodLment o~ the present invention will now b~
de~cribed with reference ~o Fig. 4. The di~ferences ~rom th~ first ~n~Dod-m~nt will m~inly ~e diYcussed betow, an~
like ox the ~;ame ~eferenc~3 numerals ~re given to those!
component~ that are like or the same as the corre~3ponding component~ of the fir~t em~o~i~ent.
A xecond suction passage 101, defined 1n ~he cyllnder block 11, communic ~te~ the ~hutte~ eh~mbex ~7 wlth the crank ch~ h~ lS. Refrigerant gas supplied to the shutter c~amber 27 fro~n the suction pa~;sage 32 is drawn into the crank chamber 15 via the second suction passage 1~1.
An intro~uction passa~e 102 co~m~nicates the c~ank chamber 15 with ~he suction chamber 37. Refrigerant gas in the crank chamber 15 is drawrl into the sUCtion chamber 37 via ~he introdu~tion passage 102. The passage 10~ includes a first pa6sage 1~6, through holes 10~, a secon~ pa~a~e 103~ a valve cham~er 10~ and a hole 105a. The fir~ p~ e 146 is definecl c~t ~he cen~er portion of the rot~ry ~:ha~t 16 along the axis ~f the ~haft 16. The fi~t passage 146 ha~
an ~nlet 146a, which opens to the c~ank chamber lS in ~he vicinity of the lip 6eal 2~, and an outlet 146b, which opens in ~he inter.ior of the shutter 28. A plurality of ~hxou~h hole~ 104 aLe fo~med in the periphexal wall near the rear end of the ~hutter Z8, which communicate th~ inte~ior o~ the shutter Z8 with the second past;age 1~3, whlch ls c}eflned ln the cy~inder ~lock 11 and the valve plate 14. The valve chS~-nh~ 105 i6 defined in the rear hc~l~ing 13 and is communicated with the second pagsa~e 103. The hole lOSa c~ - n; cates the ~alve chamber 105 with the suction chalnbe 37.
.
A tapered outlet 106 is de~ined in the downst~eam end of the secon~ passage 103, which opens to the ~al~e chamber 105. A ~alve bo~ 1O7, whi~h f~tion~ a~ a spool valve, i6 slidably housed in the valve cham~er 105. A tapered restricter 108 ix defined on an end of ~he valve body 107 facing the tapered outlet 10~ of the pas~age 103. A spring 109 extends be~ween ~he valve bo~y 107 and the w~ll o~ the val~e chamber 105 and urge~ the valve bod~ 107 away from ~he outlet 1~6 ol~ ~he passage lV3.
A pressure con~rol chamber lll is define~ b~ the rear end ~ace of the valve body 107 and th~ valve chamber 105. A
pressu~e ~upply pa~6age 110 is defined in the rear housing 13 ~nd co~munic~tefi the discharge cha~ber 38 with the chamber 111. The ~isplacement cont~ol valve 49 i~
~ccommodated in the rear hou~ing ~3 and is locate~ in the passaqe 110. A pressure ~elease pa~sage 112 i~ defined in the re~r hou~ing 13, the valve plate 14 and the ~ylinder blo~ 11 and ~ommunicate~ the chamber 111 with the crank chamber 15.
When the co~pres~or is opexating, refri~erant gas in the external ref~igeran~ circuit 52 i~ drawn into the crank chamber ~5 via the suction pa~age 32, the shutter chambe~
27 and ~he second suction pas~age }0}. Refrigerant g~s in the crank ch~mber 15 is then d~awn into the 6uction chamber 37 v1a the ~n~roduction pa~isage 102, which includ~ t~he first pa~sage 14~, the through hole 10~, ~he second p~age 103, the ~al~e chamber 105 and the hole 105a. The crank chawber 15 consti~utes a part of ~he pas~age between the re~rige~ant circui~ 52 and the suction ~hamber 37.
If the cooling load i~ ~reat, the curren~ value t~ the coil 63 in the valve 4g ~s ~ncreased. ~hi~; inc~ease~ the magnitude of the ~ttractive force ~etween the ~ore 78 and the plunger B0 thereby increasing the re~ultant force urgin~
the~valve body 67 in a direction clasing the valve hole 68.
Decrea~ing the opening between the valve hole 68 and the v~lve body ~7 redu~e~ the amount of gas flow from the discharge ch~mbe~ 38 to the preg~ure control ch~m~er 111 via the ~upply pa~age 110. Refrigerant gas in the cha~be~ 111, ~ on ~e o~er hand, ~low~ ln~o t~e crank chambe~ 15 via the pascag~ 112. Thi~ lo~orG tho p~o~ in the chambe~ 111 thereb~ mo~ing th~ ~alve body 107 rearward, or away from the 3~ tapered outlet 106. Acco~dingly, th~ re~tric~ion of the outle~ 10~ by the ~est~icte~ 108 of the valve body 107 i~
decreased. D(3creasing the re~triction, or increasing the opening of the olltlet 106, increases the amount of ~as f low from 'che crank chamber 15 into the Suction ~ham~er 37 via the passage 102. This inc~l:ea~3es the prexsure in the suction chan~ber 37. rrherefore~ the difference 3~etween the p~ess~l~e Pc in ~he crank cham~er lS and the pressure ln each cylinc~r bcre 11~ i~ sm~ll. ~hi~ incre~9e~ the inclination of ~ho swash pla~e 22, there~y a~.lowing the compressor to operate ~t a large displacement.
When the valve hole 68 in the valve ~9 is completely clo~ied ~y the valve body 67, the supply passage 110 is closed. Thi~ ~tops the :supp~y of refrigerant g~; from the di~charge chambe~ 38 to th~ pr-s~ur~ controL ch~mbe~ ~11.
This ~urther lower6 the pre~sure in ~he pre~sure control chamber 111 therehy ~izinn the openin~ between ~he outlet 106 and the valve body 107. Thus, the pres~u~e in the suction cha~ber 37 is substantially e~ual to ~he pressure ~c in the crank chamber 15. ~he inclina~ion of the 5wash plate 22 thus b~cofi.e~.maximu~, and the compressor operates at the maximum di~place~ent. When the ~uppl~
pa~;~;age 110 i clo~ed by the valve 4g, refri~erant gas in th~ di~ahar~o chamb~ 38 iL ~uppli~d t~ tho r~frigora~t ci~cuit 5~ and L8 not ~upplied to ~he ~rank chamber 15 via the pa~sage~ 110 and 112.
Suppo~e the cooling lo~d i~ small, the ~uxrent value to the coil 63 in the valve 4~ i~ lowered. ~his decrea~es th~
~agnltude Or the attractive f~rce between the ~e 78 ~n~
th~ plung~r 80 th~r~y d~a~asing th~ rQs~ltant fo~ce that urge~ the valve body 67 in a di~ection closing the valve hole 68. Increa6inq the opening between valve hole ~8 and the valve }~ody 67 increases ~he a~nount of gas flow from the ~ischarge chamber 38 to the pressure con~ol cha~nber 111 via the ~upply passa~e llO. Thi~; incre;~Eie~ ~he pre~;~;ure in the chamber 111 thereby moving the valve body 107 forward, or toward t;he tapered outlet lO~. Acco~clin~ly, ~he ~ef~triction 5 between the restricte~ 10~ and the ou~let 1~6 i~; increa~3ed.
Increas t ng the ~es~rlctlon, ~ decrea~ing the opening of ~he ~tlet 106, deare~3e~ ~he amount ga~3 ~low f~om th~ cran3c ch~mber i5 into the ~iuction chamber 37 via the pa~;sage 102.
This lower~; th~ pressure in the ~uction chamber 37.
10 Therefore, the di~fe~ence between the pres~iure Pc in the crank chambe~ l~i and the preE;~;u~e in each cylinder bore 1 la i8 great. This decrease~ the inclination of the ~wa~h plate 22 thereby allowin~ the compress~r to ope~ate ~t a sm~ll displacement.
If the cooling load ~ecomes zero, current supply to the coil ~3 of the valve 49 i8 stopped. This elimin~te~ the magnetic att~a~ti.ve ~orce be~ween the core 78 and the plunger 80. The valve body ~7 i~ mo~e~ to a position that ~tximizeS the opening of the valve hole 6~. Accox~i~g the supply pa~sage 110 is ~ully opened. Thi~ further inerea~e~ the ga~ flow fro~ the ~ischaxge c~amber 38 to th~
p~essur~ control chamber 111 the~eb~ increa~in~ the pressure in the chambex ~11. The pressure moves the va~e body 107 forward and maximizing the res~ric~ion ~etween the outlet 2~ 106 and the valve ~o~y 107. The r-xi ~lm ~estriction minlmizes gas f Low from the crank ch~nber 15 to the suc~ion chambe~ 37 ~nd lowers th~s pressure in the ~iuction chalnber 37. Thi~ minimize~ the inclln~tion of ~he s~a~h plate 22 thereby nllowing the compre~o~ to oper~te at thQ minim~m 30 displacement.
The minimum inclination of the swash plate 2~ causes the shutter 28 to ~lo~e the supply pa~sage 32. This ~ops ga~ flow from the re~riger~nt ~ircuit 52 into the suction chamber 37. In thi~ state, refrige~ant ga6 c~rculates wi~hin the co~p~es~or traveling through the ~i~charge S ch~be~ 38, the supply pa~sa~e 110, the pressure control chz~mbe~ 111, the pressure release pas~;~ge llZ, the c:xank charnber 15, the in~::rod~lction p~ Age 1~2/ thC ~UCt:ion chambe~ 37 and the cylinder bores lla.
When the compressor is no~ operating, the p~8~sures in the chambe~s of the compre~or ar~ equalized. Th~s, the swa~h plate 22 re~urns to ~he minimum inclination posi~ion.
Thi6 cau~ies the ~hutter to close ~he suetion pas~;age 32. :tn thL~ ~tate, a s~all amount o~ liquefled refxiyerant 1~
~tored in the co~pressor. Therefo~e, when the compre~or lS start~ oper~in~ again, lub~icant in the co~pressor i8 not xemoved to the circuit 52 ~y foaming of the liquefied refrigerant.
Therefore ~he present example~ ~nd embodiments are to be con~ide~ed as illu~trative and not ~e~strictive and the invention i~ no~ ~o be limite~ to ~he details given herein but may ~e m~difie~ within ~he ~cope of the appende~ claim~.
A t~pic~l v~riable di3placement compressor includes a cylinde~ block that consti~ut~ a part of the c~pre~or hou~in~. A crank ehamb~ efi~ed in the cylinder block.
A dischaxge chamber and a ~uction chamber ~re also ~efined ~ in ~ ~OmpreS~O~. A ~h~ugh hol~ is de~ined ~t the center portion of th~ cylind~r blo~k. ~ plurality of cylin~e~
bo~es exten~ th~ou~h the c~linder block and are located about the through ho~e. The cylinder ~o~es are spaced apart at equal intervals. The ~hxou~h hole i~ connected ~o an external refrigerant circuit. Re~rigerant gas in the circuit i~ drawn into the suction chamber via a suc~ion passage and the through hole.
A ~ot~y shaft is rotatably supported i~ the crank cha~ber. A cam plate i~ ~uppo~ted by the xotaxy sha~t in the crank chamber. The inclination of the cam plate i~
va~ied in accordance with the dif~erence between the pressure in the crank chamber and the pre~ure in the cylinder bores. The stroke of each pi~ton i~ va~ie~ ln .
a~cordance with the inclination of the cam plate. When the inclination of the ~am plate i~ increa6ed, the ~isplacement of the compres~ox is increased, ~or~ingly. ~ ~ecreased inclination o~ the plate l~wer~ the ~ompressor'~
displacement.
The ~:omp~eE~or i6 p~vid~cl with a di~charg~ chamber that is conne~ted to the crank cham~er ~y a s~pply pa~age.
A di~placement control val~e i~ located in the supply pas~age. The control valve ~ntrols the flow rate of re~rigerant gas from the discharge chamber to ~he Grank chamber thereby ~ontrolling the pre~sure in ~he cr~nk chamber.
A spool-like shutter is accommodate~ in the throu~h hole in the cylin~er block. The ~hutt~ slides in~5 ~ccor~ance with changes in the inclination of the cam pla~e the lnclination decreases, the 3huttex narrows the passage between ~he su~tion p~ge an~ the suction chamber.
If the cam plate xeaches the ~ini~u~ inclination, the shu~er dlsconnec~s the suc~lon cha~be~ from the sucti~n~0 pa~age.
- The control v~lve increa~es the pressure in the cr~nk ~ham~er for re-inc~easing the inclination cf the ca~ plate.
A~ khe same time, the shutter opens the suction passage thereb~ communica~ing the passage with the suction passage again.
Refrigerant ~o~den~ed in the external re~rige~an~
~i~cuit may ~e li~uefled ~y a change in the ambient ~emperatu~e. ~ f the ~hutter does not completely close the suction p~sage when the compre~sor is not operating, the ~iquefied refrigerant in the circuit may flow into the compxe~sor. The lique~ied ref~i~erant is then mixed with the lubLica~t in the compressor. When operation of the compre~sor is resu~ed, the liquefied refrigerant in the compressor may foam up and quickl~ flows back to the refrigerant clrcuit. Th$s also ~11~V~5 lub~icAnt mixed with the liquefied ~e~~iger~t from the Cvmpr~sBO~ . Thus, lubrication of the compLeSsO~ may ~ecome insufficient.
$1T~MARY OF TH~ lNV~NTION
~ccordingly, it is an o~ectlve of the present in~ention to provide a construction for lubricati~g each moving part in a compr~ o~ wh~3n tho c~mpre~or ~start~
operating fxo~ a ~tationar~ s~ate .
To achieve the foregoing and other objectiv-2s and in ~5 acco~dance with the ~urpose of the present invention, a compressor having a cam plate mounted on a dxive 6haft for in~egral rota~lon t~erewith and a piston cuupled t~ the cnm plat~ i~ provid~d. The cam pla~ tiltabl~ ~tw~Qn it~
maxim~m inclining po~ition and its mini~u~n inclining p~sition wi~h xespect to an axis of the dx-ive shaft. The piston reciprocates in a cylinder bore by a 6~xoke based on an inclined angle o~ the cam plate to Compress gas suppliecl to ~he cylinder bore from an external gas cirC~it and to discha~ge ~he compxe~sed g~s to the ex~e~nal gas circuit.
~he compLessor lncludes a gas pa~sage connecting the ~xto~n~l ga~ ~i~c~i~ to th~ int~rio~ o~ c~mp~e~so~, ~
shut~e~ body for selectively connec~ing an~ disconnecting the gas pa'~sage wi~h the external qas circuit, and ~iasing ~eans for ~iasing the ghutter ~ody to disconnect the gas pa~s~ge w~th the external gas circuit when the compressor i~
-Ln an inoperati~e ~tate.
BRlEF D~;SC~IPTION t:~F THE: DRAWINGS
Pig. L i~3 a cro~ sec~lonal view lllustrating a v~ri~le di~placemen~ comp~e~cor according ~o ~ ~ir~t ~ -t ~f the pre~en~ invention;
Fig. 2 is a cross-sectional ~~iew illustral~ing the compresso~ of Fig. 1 when the inclination of the sw~f;h plate is mi rti -;
Fig. 3 is a cxo~;s ~;ec!tional view illu~tra~ing a compressor acc~rdin~ to a second embodiment of the presen~
inven~ion; and Fig. 4 i~ a cro~ sectional vie~ illustrating a co~p~e~o~ accor~in~ ~o a third embodimen~ of th~ pxesent invention DETAILED ~ESCRIPTION OF THE p~FE~RE~ EMBODIMENTS
A variable displacement compre~60r accor~ing to a first e~bodiment of the pre~ent inv~n~ion ~ill now be descri~ed with ~e~erence t~ Flgs. 1 an~ ~.
A cylinder block 11 constitute~ a part o~ the co~pre~or hou~ing. A front housing 1~ is secured ~o the fron'c end face of ~ eylinder block 11. A rear hc1using 13 is secured to the rear end face o~ the cylinde~ block 11 with a valve pla~e 14 in ~etween. A crank chamb~r 15 is de~ined by 'che inner wall~ c~f the front hou~;ing 1~ and the front end face of the cyli~d~r bl~ck 11.
A rotary shaft 16 is rotatabl~ supported in th~ front housing 12 and the cyl~nder block 11. The fron~ end of the rotary shaft 1~ protrudes f~om the crank chamber 15 and is secured to a pulley 17. ~he pulley 17 is directly ~oupled to an external drive E;ource (a ~~ehic~le en~ine E in this en~bodiment) ~y a belt 18. The c:~ompreE~;or of thls embocliment ts a clutchles~ type v~i~l~ di~pl~e~ent c~mp~en~or having no clutch between the ro~a~y ~haft 16 and the drive source.
~he p~lley 17 is ~upport~d by the f~ont housing 12 with an angular bearing 19. The ang~lar bearing 19 txan~fers thru~t and radial lo~ds that act on ~e pulley 17 to ~he hou~in~
12.
A lip seal 2~ is located be~ween the rotary shaft 16 and the ~ront hou~ 12 for ~ealing the crank chamber lS.
The lip ~eal 20 prevents the pre~sure in ~he c~ank chamber 15 from leaking.
A subs~antiall~ di~k-like ~wash pla~e 22 is s~pported by the rota~y sha~ 16 in the crank ~hamber lS to be slida~le along and tiltable with regpec~ ~o ~he axls o~ the ~haft 16. ~he swa~h plate 2~ i8 provided with a pair of guiding pin~ 23, e~h having a g~id~ ball at its distal end.
A rotor Zl is fixed to the rotary shaft 1~ in the crank ~ha~be~ lS. The rotor 21 rota~es integrally with the xotar~
shaft 16. The rotor 21 ha~ a ~upport arm 24 pxotru~ing toward the ~;wa~;h plate 2~. A pair of guic~e ho~es 25 are formed in the support arm 24~ ~ach guide pin 23 is slidably fitted lnto the corre~ponc~.~ng gulde hole Z5. The ~ooperution of the ~rm 24 ~n~ the guid~ plnG ~3 permit~ th~
~wash plate 2~ to rotate to~ether with the rotary shaft 16.
The cooperation al~o ~uides the tilting of th~ swash plate 2~ and the movement of the swash plate 22 along the axis of ~ 5 .
-the rotaxy ~haft 16. A~ the 8~a~h plate 22 sli~es rearwar~
toward the cylindex block 11, the inclination of the sw~h plate 2Z de~reases.
A fir~t coil spring 85 is located be~ween t~e ro~x 21 and the ~swash plate 22. ~h~ X ir~ apri ng ~5 ~rges th~3 E;wash plate 22 x~s~war~, or in a di~e~ion de~reasing the inclination of the swash plate 2~. The rotor 21 is provided ~ith a pro~ectioll 2 la on its rear end ~ace . The abutment of the ~wash plate 22 agains.t the projection 21a prevent~ the 1~ inclina~ion of the swash plate 2~ beyond the pre~etermined maximum inclination.
~ ~h~tter chan~ber 27 i~ dQ~in~ at thQ cont~r portion of the Gylinder block 11 and extend~ along the axis of the rotary shaft 16. A hollow cylindrical ~hutter 2~ with a close~ end is accom~odated in the ~hutte~ chamber 27. The ~hutte~ 28 slides along ~he axis of the rotary shaft 16.
The shutter ~8 has a large diameter portion 28a and a s~ll diame~er portion 28b. ~ 8econd coil spring 86 is located between a step, which i~i de~fined by the l~rge dinme~ter portion 2Ba and the small diameter po~ion 28b, and a w~ll of the shutter chamber 27. ~he se~ond coil spring ~6 u~ges the ~ shlltte~ ~8 toward the swash plate 2~ . The urging forc~e o~ the fir~;t sprin~ 85 is greater ~han the force of ~he second spring 8 6 .
The rear end o~ the rotary shaft 16 Ls inse~ted in the ~huttGx 2~. A radial b~aring 30 io ~ix~d to th~ inn~ wa~l of the large di~meter po~tion 28a of the shutte~ 30 by a snap ring 31. Thexefore, the ~adial ~earing 30 ~oves with the shutter 28 along the ~xi~ of the xo~ary ~ihaft 16. The rear end of the rotary shaft 16 is ~uppo~te~ ~y the inner CA 02207257 l997-06-06 wall of the ~hutter chambeL 27 with the radial bearing 30 and the shutter 28 in between.
A suction passage 32 is defined at the center portion of the reax housing 13 and the valve pla~e 14. T~e pa~sage 32 is aligned with the RXi~3 o f the rote.~y ~ha~t 16 and i8 c~ nica~d with th~ shuttor ch~ ~ 27. The suction pa~age 32 function~ as a suction p~e6~ure area. A
p~sitioning ~urface 33 is fo~med on the v~lve plate 14 about the inner opening of ~he suction passa~e 32. The reax end of the ~hu~te~ 28 a~uts against ~he posi~ioning 8urface 33.
Abutment of the shutter 28 against the po~itioning su~face 33 prevents ~he shut~er 28 from ~oving further rearward away from the swash pl~e ~. The ~butment ~12~o di~connects the suc~ion pa~age 32 from the shutter chamber 2~.
A thrust bearing 34 is suppor~e~ on the rotary ~haft 16 an~ is located between the ~wash pl~te 22 and the ~hutter 28. Th~ th~t bearing 34 8:Licle8 along the axi~i of the rotary shaft 16 and is constantly retalne~ be~w~en ~he swa~h plate 22 and the sh~tter 2~ by the fc~rce of the 2!~cond spring 86. The thrust be~ing 34 prevents ~he rotation of the ~wash plate 22 from being transmit~ed to the ~hutter Z8.
The swash plate 22 ~oves rearwar~ as its inclina~ion decreases. As it moves rearw~, the swash plate 22 p~shes the shu~ter 28 rearward through the ~hrust bearing 34.
Accc~rdingly, tlle shutter 28 moves ~oward the pc~sitic~nir~g ~urfac~3 3~l againE;t th~ fo~cc~ o~ ~ho .i;~con~ s~p:~ing 86. ~
illustrate~ by a ~ashed line and a continuous line in Figs.
1 and 2, the rear end of the ~hutter ~8 abuts against the positioning surface 33 when ~he xwash plate 22 reache~ the minimum inclinati~n. In thi~ sta~e, the shutter Z8 is located at the close~ position ~ox disconnectin~ the shutter chamber 27 ~rom the suc~ion ~a~sage 32.
A plurality of ~ylin~er bores lla extend ~h~ou~h the cylincler block 11 and a~e located d~ut ~he axl~ of ~he rota~y ~ha~t 16. ~he cylinder b~r~ }~a ~xe spaced up~t a~
equal interval~. A ~inglo--h~.d~3d pi~ton 3S is acconmodated in each cylindex bore lla. A pai~ of semisphe~icaL shoe~ 3fi are fi~ted between each pi~ton 35 and the swash plate 22. A
semispherical portion and ~ flat portion are defined on each ~hoe 36. The ~emi~pherical por~ion slidably contac~s the pi~ton 35 while the ~~at portion slida~l~ contact~ the swash pl~te ~?. The swash plate 22 i~ ro~ated by the rotary ~haft 16 through the rotor 21. The ~t~ting ~ ?nt of the ~wa3h pla~e 22 i~ transmitted to each pis~on 35 th~ou~h the shoes 3G and is conver~ed ~o linear reciprocating movement of each piston 35 in the a~s3ociated cylinder bore lla.
A suction chamber 37 is de~ined in ~he center po~tion of the rear housing ~3. ~he suction chamber 37 is commun~cated wlth ~he ~hut~ex chamber 2 7 via a com~nicntion hole 45. A discharge chambex 38 is defined about the suc~ion chambe~ 37 in the rear housing 13. Suc:ti~n ports 39 ~nd discharge port~ ~0 a~e formed in the valve plate 14.
Each ~u~tio~ port 3g and ~ach discharge por~ 40 correspond to one o~ the cylindex bores lla. Suction valve flaps 41 are forme~ on the valve plate 14 . ~a~h suction valYe flap 41 correspon~s to one of the suctLon por~ 39 ~ischarge valve ~laps 4Z are fc~med ~n the vn~r~ pl~t~ 14. E~ch di~charge v~lve flap 42 co~respond~ to one of the di~cha~ç~e po~ts 40.
A~ each pis~on 3S moves from the top dead center to the bottom deacl c~nter in t.he ~sociated c~linder bore lla, refrigerant gas in the suction cham~er 37 is ~awn into each cylinder bore lla through ~he associated suction port 39 while causing the ~s~ociat~d suction valve flap 41 to flex to an open position. As each piston 35 moves from the bo~om dea~ cent~r to the top dead center ln the as~ociated cyl i n~r bore llo.~ refrig~x~nt ga~ i~ aompxQ6~;~d in th~
cylinde~ ho~e ~la and di~charged to the discharge cha~ber 38 through ~he a~ociated di~charge port 4~ while causing the associ~ed di~charge valve flap 42 to flex ~o an open position. Retainers 43 are ~ormed on the valve plate 14.
Each retainer 43 corresponds to one of the ~i~charge ~alve ~lap~ 42. The openin~ amount o~ each diLcharge val~e flap 42 is ~e~ined by ~ontac~ between the valve flap 42 and the ~;~oci~ted ;retainer 43.
A thrust bearing 44 is located ~etween the f~on~
housing 12 and the rotor 21. The thrust bearin~ 44 carries the reactive force ~f ga~ compres~ion acting on the rotor ~1 through the pistons 35 and the swa~ pla~e 22.
~0 A pxessure release passage 46 i6 defined at the cent~r portion of the rotary shaft 16. The pressure relea$é
pa~age 46 has ~n inlet 4~a, whi~h open~ to the crank chamber 15 in the vicinity of the lip ~eal 20, and an ou~let 46b, which opens to the interior of ~he ~hutter 28. A
pres~ure release hole 47 is formed in the peripheral wall near the rear end of the shu~ter 2~ ~he hole 47 comm~nic~oa th~ interior of the sh~t~er 28 with th~ ah~tte~
chamber 27.
A supply pa~age i8 i~ defined in the rear housing 13, the valve plate 14 and the cylinder block 11 fo~
g -communicating the dis~ha~ chambe~ 38 with the crank cha~e~ 15. A displacement control valve 49 is accommodated in ~he rear housing 13 ~i~way in the supply passage 4~. A
pressu~e introduction pas~age SQ is defined in the ~edx S housing 13 for com~unicating the control valve 49 with the ~uction pa~sage 32. Thus, the s~lction pre~3ure :P6 i~;
communicated with the ~nt~ol valve 49.
An outlet port ~1 is fo~med in the cylinder block 11 and iS ~o~municated with the discharge chamber 38. ~he outlet por~ Sl is connected to the ~uction pas~age 32 by an external refrigerant circuit 52. The refrigerant circui~ 52 includes a conden~er 53, an e~pan~on val~e 5~ and an evaporator 55. A temperature sensor 5~ is loc~ted in the vi~inity o~ the evapo~ator 5S. The temperat~re sens~r 56 detects the temperature of the evaporator 55 and issues ~ignals relating ~o the detec~ed t~mperature to a computer 57. ~he computex 57 is connected to v~i~u~ ~evices incl~ding a temperature adjuster 58, a passenger c~mpa~ment temperature ~ensor Sg, an ai~ conditioner ~arting switch 60 ~0 and an engi~e speed ~en~o~ ~1. A passenger sets a desirable compartment te~per~tu~e ~y the temperatuxe adjust~r 58.
- The computer 57 computes a cu~en~ value for the control valve 4~ ~ased on various condition~ including, for éxa~ple, a ~arget ~empexatu~e ~et ~y the temperature ZS adju3tex 58, the temperatur~ de~ected b~ the te~perature sen~or 56 r ~he pas~enger ~ompartment temperature ~e~ected by the tempera~ure serlsox 59, the engine speed detected by the engine ~peed ~en~or 61 an~ an ON~OFF ~ignal from th~
starting ~witch G0. The computer 57 transmits the computed ~u~ent valu~ to a driver 62 The ~river 62 ~end~ a current having the value ~ran~mitted from the computer 57 to ~ ~oil 63 of a ~olenoid 65 in the valve 4~. The ~oil 63 an~ the solenoid 65 will be desc~ibe~ later. Th~ con~itions for determining the current value ~or the valve 49 may includes dat~ other than those listed above, ior ex~mple, ~he data S may incl~de ~he temperature out6ide o~ ~he ~hicle..
The cont~ol ~l~e 49 i~cl~den a ho~sing 64 and th~
solenoid 6S, which a~e secured to each other. A valve chamber ~6 is defined bet~een the housing 64 and the ~lenoi~ 65. The valve cha~be~ 66 is connected to the ~ischa~ge chamber 38 by the supply pa~sage 48. A valve b~dy 67 i~ arranged in the valve ¢ham~er 66. The area about the opening of the valve hole ~8 function~ as a valve ~eat, agains~ which a top end o~ the valve body ~7 abut~i. A c~i}.
sprirlg 69 extends be~ween the valve ~ody 67 and a w~ll of th~ valv~ cha~b~r 66.
A pressure sensing chamber 71 i8 defined at the upper portion of the housin~ ~4. The chaInber 71 is provided wi~h a bellows 73 and is conne~ted ~o the ~uction passage 32 by the p~es~u~e in~roduction passage 50. Suc~lon pres~u~e PS
in the suction pasGage 3~ i~ intro~uced to the chamber 71 via th~ pa6~ago 50 an~ i~ d~t~ct~d by th~ bollows 73. The bellows 73 i~ connec~ed to the valve body 67 by a first rod 75. ~he v~lve hol~ 68 i~ co~nected to the crank chamber 1 by the ~upply passage 48.
An ac:co~unoda~lng hole 77 i~3 defined in the ~enter por~ion o~ the ~olenoid G5. A fixed 3teel core 78 iG ~itt in ~ho upp~r portion ~f the hole 77. A plunger chamber 79 is de~ined by the fixed core 78 and inner walls o~ the hole 77 at the lower por~ion o~ ~he h~le 77. A plunger 80 is slidably accommcsdated in the chamber 7Y. A coil ~:pring 81 extends between the plunge~ 8~ and the bottom of the hole 77. ~he ur~ing forc:e of the 5pring 81 is ~imaller than that of ~he coil ~iprin~ ~q. The ~:p~ing 6g u~ge~3 the valve body fi7 do~nward, while the sprin~ 81 urges the plunge~ 80 5 upward. T~i~ allow~ the lower end of the second rod 83 to constantly cont~c~ the plunger 80. In other ~o~d~, the val~re b~dy 67 ~ove~ integr~lly with the pl~nger 80 wi~h tho secon~ rod 83 in between.
A cylindrical c:oil 63 is wound about the core 78 anc~
the plunger 80. The driver 62 supplies coil 63 with a current; ll~ving a value computed by the computeI~ 57.
When thl3 ~wi~ch ~0 i~: ~urn~d on, i~ th~ compartment temperature detected by the temperature sensor 59 is e~ual to or greater ~ha~ ~ taXget temperature, the Computer 57 comm~nds the d~ive~ ~2 to excite solenoid 6~. A current i~
~upplied to the ~oil 63, accordingly. This generates a ~agnetic attractive force betw~en ~he core 78 and the plunger 80. The attractive force urges the valve ~ody 67 in a di~ecti~n clo5ing the valve hole 68. On the other h~nd, ~he length of the bellow~ 73 changes in accordance with the suction pres~ure Ps in the suction pa~ e 3~, which is introduced to the pressu~e sen~ing chamber ?1 via the pas~;ag~ 50. The ~hange~ in the length of the bellows 73 are trans~itted to the valve bo~ 67. The higher t~e suction pre~;~u~e P~: i8~ the ~horter the bellows 73 }:~ecolne~. As the ~ellows 73 beco~es sho~te~, t~e ~ellows 73 pulls the valve ):oc~ G7 in ~ ~i~c~c~cion c~ ~ing the vcllve hole 6~.
The opening area be~ween the valve body 67 and the valve hole 68 i~ determined hy the e~uilibrium of forces a~ting on the valve body 67. Specifically, the opening area -CA 02207257 l997-06-06 i8 d~at~rmined b~ the equilibrium po~ n of the body h7, which i~ affected b~ the force o~ the ~vlenoid 65 transmi~ted through the second rod 83, ~he fol~ce o~ the bellow~ 73 and ~he force o~ the sp~ing ~g.
~;u~pose the cooling load is great, the l:em~?era~:u~e in the vehiele c~mp~t~ent detected by th~ ~60r 59 i~
si~nificantly higher than a target te~pe~ature set by the ~emperature a~juster 58 and the suction pre~sure P~ is high.
The computer 57 sets a higher target current value when the difference be~7~n the detected temperatu~e and the tar~et temperature is gre~t. This inCreAseS the magnitude of the attractive force ~etween the c~re 78 and the plunger ~0 the~eby inCrea8in~ the resultant rOr~e urglng ~he val.ve body ~7 in a dire~tion closing the ~a~ve hole 68. Thi~ Iower~
th~ valuQ of pr~s~ure Ps required for opening of the ~al~re hole ~8. Increa~ing the value of the current t~ ~he ~alve 49 cau~es the valve 4g to maintain a lower suction pre~sure P~
A ~maller opening area between the valve bod~ 67 and the valv~ hole 68 decrea~es ~he xe~rigeran~ ga~ f ~ ow fro~
the di~h~rg~ chamb~r 38 to the c~ank chamber 15 via the pas~age 48. The re~rige~nt ~as in the crank chamber 15 flows into ~he suc~ion chamber 37 vi~ the pressure ~elease passa~e 4~ and the pressure relea~e hole 47. This lowers 25 the pressure Pc in the c~ank chambe~ 15. ~urther, when the cooling load i~ great, ~he suction pressure Ps is hi~h.
~ccordingly, the pre~5ure in each cylin~er bore lla i~ hi~h.
The~efore, the di~fe~ence between th~ pr~G~u~ Rc ;n th~
crank chamber 15 an~ the pressure in ~ach cylin~er lla 1~
s~all. This incxea~e~ the inclina~ion of ~he swash plate 22, thereby allowing the compre~;or to c~perate at a large , dis~lacemen~.
When the valve hcle 68 in the val~e 4Y i~ completely close~ b~ the valve body ~7, the supply pa~sage 48 is clo~ed. Thi~ stops the ~iu~ply of the hi~hly pressurlzed refriger~nt ~ab i~ th~ ~i~ch~rge ch~mber 38 ~o ~.he ~ank ch~mb~ ;. q'h-r~i~or~ ch~ prns~urc~ Pc in ~he crank chaTnber 15 becomes substantially the ~ame aç the low pressure Ps in the SuCtion chamber 37. The in~lination of the swa~h plate 22 thu~ becomes maximu~ a~ shown in Fi~. 1, and ~he compre~or op~rates at the ~y~ m displace~ent. The abutment of th~ swash plate 2~ and the p~o}ection ~la of the xotor Zl prevent~ the swash pla~e 22 from inclining ~eyond th~ ~ _~e~ermined ~Xi~ i~clinc~tion.
Suppo~e the co~ling load is S~dll~ the difference between the compartment temperature detec~ed by the senso~
5g and the targe~ temperature ~et by the temper~tu~e adjuster 58 is s~all and ~he suction pressure Ps is l~w.
The computer 57 command~ the d~ive~ 62 to decrease the cu~rent value t~ the c~il 63 ~f the ~lve 49 for n ~m~ller difference between the de~ected tempe~ature and the tar~et temperature. This decreases the magnitude of the attractive force between the core 78 and the plungex BO the~eby ~ecreasing the resultant force ur~ing the valve body 67 in a direction clo~ing the valve ho~e 68. Thi~ increa~e~ the value of the pressure PB tha~ will oper~ the valve hole 68.
Decrea~ing the value o~ the current to the valve 49 cau~e~
the ~nl~e 49 to mnintnin n hiyher ~tion p~es~e P~-A lars~er opening area between the valve body 6? and thevalve h~le 68 incxea~e~ the refrigerant gas ~low from the 30 dis~ha~ge chamber 38 to the crank chamber 1~. This inc~eases the pressure P~ in the c~ank chambel 15. Furthe~, ' when the cooling lo~d is smal~, the ~uction pre~sure Ps i~
low and the pres~re in each cylin~er bo~e lla is low Therefore, the difference between the pressure P~ in the crank chamber 15 and the ~ressure in each cylinde~ lla is gLeat. This decre~e~ the incllnation or ~he ~ash plate 22 thereby all~winy the cc..~l~8~r to oper~te at a ~mall di6placement.
A~ cooling load app~oache~ zero, the temperat~e of the evapo~ator 55 in ~he refrigerant circuit 52 drops to a f~o~t formin~ temperature. When the tempera~uxe ~ensor 56 detects.
a temperature that i8 lower than the frost formin~
temperatuxer the computer S7 ~ -nd~ the ~iver 62 t~
de-excite the ~olenoid 65. The driver 62 stops sendi~g cur~ent to the coil 63, accordingly. This eliminate~ ~he ~agnetic attractive force between the ~ore 78 and the plunger 80. The valve bo~y ~7 is then moved by the fo~ce of the ~pxing 69 again~t the force of ~he ~p~ing 81 transmitted by the plunger 8~ and ~he second rod 83. The valve ~ody 67 is moved in a direction opening the valve hole 68. Thi~
maximizes the opening a~e~ between the valve body ~7 a~d the valvo hol~ 6~. Acco~ding~y, th~ gas flow from the ~ischarge cha~ber 38 to the crank ~h~mbe~ 15 i~ inc~ea~ed. This fu~the~ raises the pressure Pc in the cx~nk ch~eL lS
thereb~ minimizing the inclination ~ the swash plate 22.
The com~re~or thus opera~es at the mini~u~ displacement.
When the ~wltcl~ 60 is turned ~ff ~ the c~mp~te~ 57 c ~ tho dri-~or 62 to t3q c~Y~ e the çtolenoid 65. Thi~
also ~inimizex the inclination o~ the swash plate 22.
30 As described above, when ~he value of ~he current to the coil 63 is increased, the val~e hody 67 o~ the valve 4 allows the opening ~ea of the valve hole 68 to ~e controlled by a lower ~uction pressure Ps. When the value of ~he cur~ent to ~he coil 63 i~ decrea~e~, on the othe~
hand, the valve body 67 allows the opening area o~ ~he valve hole 6~ to be controlled by a higher suc~ion ~re~ure P~.
The co~pre~or control~P the inclination o~ th~ ~a~h plat~
~2 to ad~ust its di~p~ace~ent thereb~ maintaining a target 8uCtLOn pressU~ce pF~ . ~hat is, the valve 49 change~; the target value of ~he su~tion pressure Ps in accordance ~ith the v~lue of the current supplied ther~to. Al~, the ~alve 4g ~ause~ the compr~ssor to operate at the minimum di~pla~emen~ ~or an~ given suction pressure Ps. ~
compressor equipped with ~he c~ntrol valve 49 v~xle~ the cooling ability of the air conditione~.
The shutt~ 28 slides in accordance with the tilting motion of the ~wa~h pla~e 22. As the inclination of the ~wa~h plate ~2 decreases, the shutter 28 gxa~ually reduces the cross-sectional area of ~he pas~age between the suction passage 32 and the s~ction chamber 37. ~his ~rad~ally reduces the amount of refrigerant gas that ente~s the ~QU~tiOn ch~n~D~r 37 from th~ ~tion pas~a~e 32. The amo~nt of ~efrigerant gas that is d~awn into the cylinder bores lla fxo~ the s~ction ~hamber 37 gradually decrea~e~, accordingly. As a re~:ult, the displacement of the compres~or gradually decreases. This graduall~ lowers the discha~ge p~essu~e ~d of the compressor. The load torque of the ~:ompxessox thu~ gradual:Ly decrea~;es. In t}~5.s manner, the lo~d torq~e for oper~tin~ the com~e~oor doe6 no~ ch~ngc dramatically in a short time when the displacement dec~ea~es ~rom the rQxi~lm to the mini~um. The shock ~hat accompanies load torq~le ~luctuations is therefore le~ened.
.
When the inclination of ~he swash plate Z2 is m-nimum, the shutter 2B abuts against the positionin~ surface 33.
The abutment of the shutter 28 agains~ the po~itioning ~rface 33 prev~nt~ the inclination of the swash plate 2Z
S fxom being sma~le~ than the pre~e~ermined minimum inclination. The abutment ~1160 clisconr~ects ~che suc~lon pa~ge 32 from the suction chAmber 37. Thi6 Gtop~ tho ga~
f}ow from the refrigerant circuit 52 to the ~uction chamber 37 thereby stoppin~ ~he circulation of ref~igerant g~
between the circuit 52 an~ the compre~or.
The n~ini I inclination of the swash plate ~2 is slightly larger than zero degrees. Zero degrees refer~ to the angle o~ ~he swa6h plate~ inclin~ion when it perpendicular to the axis of t~e rotary shaft 1~.
Therefore, even if the inclination of the swash plate 22 is minimum, refrigerant gas in the cylinder bores lla is discharge~ to the discharge chamber 38 and the compressor opexate~ at the minimum displace~en~. The refrigerant gas discharged to ~he discha~ge chamber 38 from ~he ~ylinder ~Q boxes lla is drawn into the crank chamber 15 ~hrough the supply p~ e 4~. The refrigerant ga~ in the c~ank cham~er 15 i~ drawn back into the cylin~r ~ores 11~ th~ough the pre~ur~ release passage 4~, a pres~ure release hole 47 and the suction chamber 37. That is, when ~he inclination of the swash plate 22 is minilnum~ refrigerant ga~ circulates within the compressor traveling through the discharge chambex 38, the supply passage 48, the crank ch~mbe~ lS, the pres~uLe ~el~ase passage 4~, ~che pre~;~ure rele~t;e hole 47 r thc ~uction ch~mber 37 ~n~ the c~linder bor~ lla. Thi~
30 circulation o~ refri~exant ga~ allowx ~he lubri~ant oil contained in the ga~ to lub~icate the moving parts o f the compress~r.
If th~3 ~wi~ch 60 iç: tu~ned cln and the inclination of the ~wa~;h Plate 22 i6 minimum, an increa~;e in the compartment temperatu~ increase~ the cooling load. Thi~
causes the comp~rtment tempe~ature detected by the sen~r ~9 to be highe~ than a targe~ te~perature ~et by the te~pe~a~ure adjuster 58. ~he compute~ 57 command6 ~he driver 6Z to excite ~he solenoid 65 in acco~dance with th~
detect~d tempera~u~e increase. ~xcitin~ the solenoid 65 close~ the supply passage 48. Thi~3 stop~; the flow of refrigerant ga~ fro~ the discharge chamber 38 into the crank chamber 15. ~he ref~iqer~n~ gas in the crank chamber 15 flow~ into the suction cham~e~ 37 via the pxe~ure release pass~ge 46. This gradually lowers the pressure Pc in the crank chamber 15 there~y moving the swash plate ~2 from the ;n--unl inclination to the maximum inclination.
As the swash plate~s Lnclination inc~e~ses, the ~OLC~
of the second fip~ing 8~ gradually pushe~ the shutter 28 away from the positioning surface 33. Thi~ gra~ually increase~
the amount of refrigerant ga~ flow from ~he suction pas~age 32 into the ~u~tion cha~er 37. Therefore, the amo~t of refrigerant gas drawn into ~he cy}indeL bo~es lla from the ~uc~ion ch~b~r 37 grQ~ually incr~a~e~ ~hi~ ~llow~ the di~plac0ment of tho comprossor to gradually in~ease. Thus, the discharge pressure Pd o~ the compxe~or grad~ally increases and the torque needed for ope~atin~ the compressor al~o gradually increases accordin~l~. In this manne~, the load torque of the compressor doe~ not change ~ramatically in a ~;hort tilne when the displacement increases from the minimum to ~he m~Y-tm~ The E;hock tnat accompanle~ load toxque fluctuation~ i~; therefore le~e~ed If ~che engine E is stopped, the cc~mpre~:o~ is al80 ~topped (that is, the ro~ation of th~ swa~h p~ate 22 is stopped). Also, the supply of cu~ren~ to the ~oil 63 in the valve 49 i~ stopped. This de-excit~s ~he 601enoid 65 thereby opening the supply pass~ge 48. The inclination of the swash plate 22 is thus minimum. I~ the nonoperatlonal state o~ ~he compressor c~ntinues, the pr~sure~ in the cha~ber~ of th~ ~Omp~O~O~ b~como ~ualiz~d and th~ swash pla~e 22 i~ kept at the minimum inclination by the iorce ~f fir6~ spri~q 85. ~he~efo~e, when the compres~or is not ~pe~ating, the interior o~ the comp~e~sor is completely disconnec~ed fxom the ~ef~igerant circuit 52. Thu~, even i~
the nonope~ationa~ state of the compre~ c~ntinue~ over a relatively long perio~ of time, llquefied refrigerant in the c~rcuit 5z i~ prevente~ from ente~ing ~he compres~or.
A~ descri~ed in the background ~ection, wh~n the compres~or i8 re-~:tarted by the engine E, a small ~unount o~
1 iquef ied ~e~rigerant may exist in the comp~es~or . Fo~ming of the li~ue~ied refrigerant is prevented ~in~e liquefled refrige~ant i~ prevented from entering the compressox.
T~Us, lubricant ~;tc>red in the compreg50r i~; preven~ed ~rom being mixed with ~h~ liquefied refrigerant and from being remo~ed to the refrigerant circui~ 52. Lubrication of the ~ov~ng parts in the compres~o~ i~ i~proved, accordingl~.
Fig. 3 shows a second e~bodiment o~ the present inven~ion. In this embodiment, an end of the guide hole Z5 . in the ar~ 21 i~ closed by a wall ~2. The hole 25 hax a U-:~h~-pcd c:~O~ e~:tion. A ~p~iny 91 ex~nd~ t~e~ the wall 92 and the ~uide pin ~3. The sprin~ 91 u~es the swash plate 22 in a direction decreasing the inclination of the plate 22. The urging ~orce of the spring 91 is g~e~ter than that of the ~pring 86, which open~ the ~hutter 28.
If the comp;~e~:sor is not operating and the pre~3sures in th~ chalnbers of the compressor a~e equalized, the swa~h plate 22 re~ches the minimum in~lination. Thi~ ~auses the shutter to close the suc::tion pa~ age 32. In thig State~
liquefied refrigerant in the refrige~ant circuit 52 is prevented from ente~ing ~he co~pxessor. There~ore, when th~
co~presyo~ 5~rt~ operQting ~in, lubricant in th~
compressOr is n~ ~emoved ~o the circuit S2 by foaming of the liquefied refrigerant.
If the pressure in the crank cham~er lS is lowered, highly pressurize~ heated ~as from the discharge cham~er 38 is drawn into the crank cham~ex 15 via ~he pa~sage 48.
Thu~, parts in the crank cha~ber 15 are exposed to the ~eated gas. ~owever, the 6p~ing 91 is loc~te~ in the arm Z4 ~5 having a U-shaped cross-se~ion an~ i~ no~ directLy exposed to ~he gas fi~w. The ~pring 91 is thus not affected by the heated gas flowin~ in the crank chambex 15. Thi~ improves 'the durabil~ty of the spring 91.
A ~hird embodLment o~ the present invention will now b~
de~cribed with reference ~o Fig. 4. The di~ferences ~rom th~ first ~n~Dod-m~nt will m~inly ~e diYcussed betow, an~
like ox the ~;ame ~eferenc~3 numerals ~re given to those!
component~ that are like or the same as the corre~3ponding component~ of the fir~t em~o~i~ent.
A xecond suction passage 101, defined 1n ~he cyllnder block 11, communic ~te~ the ~hutte~ eh~mbex ~7 wlth the crank ch~ h~ lS. Refrigerant gas supplied to the shutter c~amber 27 fro~n the suction pa~;sage 32 is drawn into the crank chamber 15 via the second suction passage 1~1.
An intro~uction passa~e 102 co~m~nicates the c~ank chamber 15 with ~he suction chamber 37. Refrigerant gas in the crank chamber 15 is drawrl into the sUCtion chamber 37 via ~he introdu~tion passage 102. The passage 10~ includes a first pa6sage 1~6, through holes 10~, a secon~ pa~a~e 103~ a valve cham~er 10~ and a hole 105a. The fir~ p~ e 146 is definecl c~t ~he cen~er portion of the rot~ry ~:ha~t 16 along the axis ~f the ~haft 16. The fi~t passage 146 ha~
an ~nlet 146a, which opens to the c~ank chamber lS in ~he vicinity of the lip 6eal 2~, and an outlet 146b, which opens in ~he inter.ior of the shutter 28. A plurality of ~hxou~h hole~ 104 aLe fo~med in the periphexal wall near the rear end of the ~hutter Z8, which communicate th~ inte~ior o~ the shutter Z8 with the second past;age 1~3, whlch ls c}eflned ln the cy~inder ~lock 11 and the valve plate 14. The valve chS~-nh~ 105 i6 defined in the rear hc~l~ing 13 and is communicated with the second pagsa~e 103. The hole lOSa c~ - n; cates the ~alve chamber 105 with the suction chalnbe 37.
.
A tapered outlet 106 is de~ined in the downst~eam end of the secon~ passage 103, which opens to the ~al~e chamber 105. A ~alve bo~ 1O7, whi~h f~tion~ a~ a spool valve, i6 slidably housed in the valve cham~er 105. A tapered restricter 108 ix defined on an end of ~he valve body 107 facing the tapered outlet 10~ of the pas~age 103. A spring 109 extends be~ween ~he valve bo~y 107 and the w~ll o~ the val~e chamber 105 and urge~ the valve bod~ 107 away from ~he outlet 1~6 ol~ ~he passage lV3.
A pressure con~rol chamber lll is define~ b~ the rear end ~ace of the valve body 107 and th~ valve chamber 105. A
pressu~e ~upply pa~6age 110 is defined in the rear housing 13 ~nd co~munic~tefi the discharge cha~ber 38 with the chamber 111. The ~isplacement cont~ol valve 49 i~
~ccommodated in the rear hou~ing ~3 and is locate~ in the passaqe 110. A pressure ~elease pa~sage 112 i~ defined in the re~r hou~ing 13, the valve plate 14 and the ~ylinder blo~ 11 and ~ommunicate~ the chamber 111 with the crank chamber 15.
When the co~pres~or is opexating, refri~erant gas in the external ref~igeran~ circuit 52 i~ drawn into the crank chamber ~5 via the suction pa~age 32, the shutter chambe~
27 and ~he second suction pas~age }0}. Refrigerant g~s in the crank ch~mber 15 is then d~awn into the 6uction chamber 37 v1a the ~n~roduction pa~isage 102, which includ~ t~he first pa~sage 14~, the through hole 10~, ~he second p~age 103, the ~al~e chamber 105 and the hole 105a. The crank chawber 15 consti~utes a part of ~he pas~age between the re~rige~ant circui~ 52 and the suction ~hamber 37.
If the cooling load i~ ~reat, the curren~ value t~ the coil 63 in the valve 4g ~s ~ncreased. ~hi~; inc~ease~ the magnitude of the ~ttractive force ~etween the ~ore 78 and the plunger B0 thereby increasing the re~ultant force urgin~
the~valve body 67 in a direction clasing the valve hole 68.
Decrea~ing the opening between the valve hole 68 and the v~lve body ~7 redu~e~ the amount of gas flow from the discharge ch~mbe~ 38 to the preg~ure control ch~m~er 111 via the ~upply pa~age 110. Refrigerant gas in the cha~be~ 111, ~ on ~e o~er hand, ~low~ ln~o t~e crank chambe~ 15 via the pascag~ 112. Thi~ lo~orG tho p~o~ in the chambe~ 111 thereb~ mo~ing th~ ~alve body 107 rearward, or away from the 3~ tapered outlet 106. Acco~dingly, th~ re~tric~ion of the outle~ 10~ by the ~est~icte~ 108 of the valve body 107 i~
decreased. D(3creasing the re~triction, or increasing the opening of the olltlet 106, increases the amount of ~as f low from 'che crank chamber 15 into the Suction ~ham~er 37 via the passage 102. This inc~l:ea~3es the prexsure in the suction chan~ber 37. rrherefore~ the difference 3~etween the p~ess~l~e Pc in ~he crank cham~er lS and the pressure ln each cylinc~r bcre 11~ i~ sm~ll. ~hi~ incre~9e~ the inclination of ~ho swash pla~e 22, there~y a~.lowing the compressor to operate ~t a large displacement.
When the valve hole 68 in the valve ~9 is completely clo~ied ~y the valve body 67, the supply passage 110 is closed. Thi~ ~tops the :supp~y of refrigerant g~; from the di~charge chambe~ 38 to th~ pr-s~ur~ controL ch~mbe~ ~11.
This ~urther lower6 the pre~sure in ~he pre~sure control chamber 111 therehy ~izinn the openin~ between ~he outlet 106 and the valve body 107. Thus, the pres~u~e in the suction cha~ber 37 is substantially e~ual to ~he pressure ~c in the crank chamber 15. ~he inclina~ion of the 5wash plate 22 thus b~cofi.e~.maximu~, and the compressor operates at the maximum di~place~ent. When the ~uppl~
pa~;~;age 110 i clo~ed by the valve 4g, refri~erant gas in th~ di~ahar~o chamb~ 38 iL ~uppli~d t~ tho r~frigora~t ci~cuit 5~ and L8 not ~upplied to ~he ~rank chamber 15 via the pa~sage~ 110 and 112.
Suppo~e the cooling lo~d i~ small, the ~uxrent value to the coil 63 in the valve 4~ i~ lowered. ~his decrea~es th~
~agnltude Or the attractive f~rce between the ~e 78 ~n~
th~ plung~r 80 th~r~y d~a~asing th~ rQs~ltant fo~ce that urge~ the valve body 67 in a di~ection closing the valve hole 68. Increa6inq the opening between valve hole ~8 and the valve }~ody 67 increases ~he a~nount of gas flow from the ~ischarge chamber 38 to the pressure con~ol cha~nber 111 via the ~upply passa~e llO. Thi~; incre;~Eie~ ~he pre~;~;ure in the chamber 111 thereby moving the valve body 107 forward, or toward t;he tapered outlet lO~. Acco~clin~ly, ~he ~ef~triction 5 between the restricte~ 10~ and the ou~let 1~6 i~; increa~3ed.
Increas t ng the ~es~rlctlon, ~ decrea~ing the opening of ~he ~tlet 106, deare~3e~ ~he amount ga~3 ~low f~om th~ cran3c ch~mber i5 into the ~iuction chamber 37 via the pa~;sage 102.
This lower~; th~ pressure in the ~uction chamber 37.
10 Therefore, the di~fe~ence between the pres~iure Pc in the crank chambe~ l~i and the preE;~;u~e in each cylinder bore 1 la i8 great. This decrease~ the inclination of the ~wa~h plate 22 thereby allowin~ the compress~r to ope~ate ~t a sm~ll displacement.
If the cooling load ~ecomes zero, current supply to the coil ~3 of the valve 49 i8 stopped. This elimin~te~ the magnetic att~a~ti.ve ~orce be~ween the core 78 and the plunger 80. The valve body ~7 i~ mo~e~ to a position that ~tximizeS the opening of the valve hole 6~. Accox~i~g the supply pa~sage 110 is ~ully opened. Thi~ further inerea~e~ the ga~ flow fro~ the ~ischaxge c~amber 38 to th~
p~essur~ control chamber 111 the~eb~ increa~in~ the pressure in the chambex ~11. The pressure moves the va~e body 107 forward and maximizing the res~ric~ion ~etween the outlet 2~ 106 and the valve ~o~y 107. The r-xi ~lm ~estriction minlmizes gas f Low from the crank ch~nber 15 to the suc~ion chambe~ 37 ~nd lowers th~s pressure in the ~iuction chalnber 37. Thi~ minimize~ the inclln~tion of ~he s~a~h plate 22 thereby nllowing the compre~o~ to oper~te at thQ minim~m 30 displacement.
The minimum inclination of the swash plate 2~ causes the shutter 28 to ~lo~e the supply pa~sage 32. This ~ops ga~ flow from the re~riger~nt ~ircuit 52 into the suction chamber 37. In thi~ state, refrige~ant ga6 c~rculates wi~hin the co~p~es~or traveling through the ~i~charge S ch~be~ 38, the supply pa~sa~e 110, the pressure control chz~mbe~ 111, the pressure release pas~;~ge llZ, the c:xank charnber 15, the in~::rod~lction p~ Age 1~2/ thC ~UCt:ion chambe~ 37 and the cylinder bores lla.
When the compressor is no~ operating, the p~8~sures in the chambe~s of the compre~or ar~ equalized. Th~s, the swa~h plate 22 re~urns to ~he minimum inclination posi~ion.
Thi6 cau~ies the ~hutter to close ~he suetion pas~;age 32. :tn thL~ ~tate, a s~all amount o~ liquefled refxiyerant 1~
~tored in the co~pressor. Therefo~e, when the compre~or lS start~ oper~in~ again, lub~icant in the co~pressor i8 not xemoved to the circuit 52 ~y foaming of the liquefied refrigerant.
Therefore ~he present example~ ~nd embodiments are to be con~ide~ed as illu~trative and not ~e~strictive and the invention i~ no~ ~o be limite~ to ~he details given herein but may ~e m~difie~ within ~he ~cope of the appende~ claim~.
Claims (10)
1. A compressor having a cam plate mounted on a drive shaft for integral rotation therewith and a piston coupled to the cam plats, said cam plate being tiltable between its maximum inclining position and its minimum inclining position with position to an axis of the drive shaft, wherein said piston reciprocates in a cylinder bore by a stroke based on an inclined angle of the cam plate to compress gas supplied to the cylinder bore from an external gas circuit and discharge the compressed gas to the external gas circuit, said compressor comprising:
a gas passage connecting the external gas circuit to the interior of compressor;
a shutter body for selectively connecting and disconnecting the gas passage with the external gas circuit:
and biasing means for biasing said shutter body to disconnect the gas passage with the external gas circuit when the compressor is in an inoperative state.
a gas passage connecting the external gas circuit to the interior of compressor;
a shutter body for selectively connecting and disconnecting the gas passage with the external gas circuit:
and biasing means for biasing said shutter body to disconnect the gas passage with the external gas circuit when the compressor is in an inoperative state.
2. The compressor as set forth in Claim 1, wherein said shutter body moves in association with an inclination of the cam plate, and wherein said shutter body disconnects the gas passage from the external gas circuit when the cam plate is in the minimum inclining position.
3. The compressor as set forth in Claim 2, wherein said biasing means comprises;
a first spring for biasing the cam plate to the minimum inclining position;
a second spring for biasing the cam plate to the maximum inclining position; and said first spring having biasing force greater than that of the second spring.
a first spring for biasing the cam plate to the minimum inclining position;
a second spring for biasing the cam plate to the maximum inclining position; and said first spring having biasing force greater than that of the second spring.
4. The compressor as set forth in Claim 3, further comprising:
said crank chamber being supplied with gas flow from the discharge chamber when pressure in the crank chamber decreases, wherein the gas flow circulates in the crank chamber (15); and said first spring being located away from a path of the gas flow.
said crank chamber being supplied with gas flow from the discharge chamber when pressure in the crank chamber decreases, wherein the gas flow circulates in the crank chamber (15); and said first spring being located away from a path of the gas flow.
5. A compressor having a piston reciprocally moving in a cylinder bore to compress gas containing oil and supplied thereto from an external refrigerant circuit via a suction chamber and discharge the compressed gas to the external refrigerant circuit via a discharge chamber, said piston being coupled to a cam plate mounted on a drive shaft for integral rotation therewith, said cam plate being tiltable between its maximum inclining position and its minimum inclining position with respect to an axis of the drive shaft, wherein said piston moves by a stroke based on an inclined angle of the cam plate, said compressor comprising:
- a gas passage connecting the external gas circuit to the interior of compressor;
a shutter body selectively connecting and disconnecting the gas passage with the external gas circuit; and first biasing means for biasing the shutter body to disconnect the gas passage with the external gas circuit when the compressor is in an inoperative state.
- a gas passage connecting the external gas circuit to the interior of compressor;
a shutter body selectively connecting and disconnecting the gas passage with the external gas circuit; and first biasing means for biasing the shutter body to disconnect the gas passage with the external gas circuit when the compressor is in an inoperative state.
6. The compressor as set forth in Claim 5, wherein said first biasing means biases the cam plate to the minimum inclining position.
7. The compressor as set forth in Claim 6, further comprising:
second biasing means for biasing the shutter body against the first biasing means; and said first biasing means having force greater than that of the second biasing means.
second biasing means for biasing the shutter body against the first biasing means; and said first biasing means having force greater than that of the second biasing means.
8. The compressor as set forth in Claim 7, wherein said shutter body moves in association with an inclination of the cam plate, and wherein said shutter body disconnects the gas passage from the external gas circuit when the cam plate is in the minimum inclining position.
9. The compressor as set forth in Claim 8, further comprising:
said crank chamber being supplied with gas flow from the discharge chamber when pressure in the crank chamber decreases, wherein the gas flow circulates in the crank chamber; and said first spring being located away from a path of the gas flow.
said crank chamber being supplied with gas flow from the discharge chamber when pressure in the crank chamber decreases, wherein the gas flow circulates in the crank chamber; and said first spring being located away from a path of the gas flow.
10. The compressor as set forth in Claim 9, further comprising:
said gas containing oil for lubricating the interior of the compressor; and said shutter body being arranged to prohibit the liquefied gas flowing into the interior of the compressor from the external gas circuit when the compressor is in an inoperative state.
said gas containing oil for lubricating the interior of the compressor; and said shutter body being arranged to prohibit the liquefied gas flowing into the interior of the compressor from the external gas circuit when the compressor is in an inoperative state.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8-145765 | 1996-06-07 | ||
| JP14576596A JP3214354B2 (en) | 1996-06-07 | 1996-06-07 | Clutchless variable displacement compressor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2207257A1 true CA2207257A1 (en) | 1997-12-07 |
Family
ID=15392651
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2207257 Abandoned CA2207257A1 (en) | 1996-06-07 | 1997-06-06 | Variable displacement compressor |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0812987A3 (en) |
| JP (1) | JP3214354B2 (en) |
| KR (1) | KR100235510B1 (en) |
| CN (1) | CN1116564C (en) |
| CA (1) | CA2207257A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4333042B2 (en) * | 2001-02-20 | 2009-09-16 | 株式会社豊田自動織機 | Control valve for variable capacity compressor |
| JP2004060644A (en) | 2002-06-05 | 2004-02-26 | Denso Corp | Compressor device and its control method |
| JP5362718B2 (en) * | 2007-07-13 | 2013-12-11 | イクセティック・マク・ゲーエムベーハー | Reciprocating piston engine |
| JP6083291B2 (en) * | 2013-03-27 | 2017-02-22 | 株式会社豊田自動織機 | Variable capacity swash plate compressor |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR970004811B1 (en) * | 1993-06-08 | 1997-04-04 | 가부시끼가이샤 도요다 지도쇽끼 세이샤꾸쇼 | Clutchless variable capacity single sided piston swash plate type compressor and method of controlling capacity |
| KR0169014B1 (en) * | 1994-05-12 | 1999-03-20 | 이소가이 찌세이 | Clutchless signal head piston type variable capacity compressor |
| JPH07310654A (en) * | 1994-05-12 | 1995-11-28 | Toyota Autom Loom Works Ltd | Clutchless single piston type variable displacement compressor |
| JP2932952B2 (en) * | 1994-12-07 | 1999-08-09 | 株式会社豊田自動織機製作所 | Clutchless variable displacement compressor |
| JP3175536B2 (en) * | 1995-06-13 | 2001-06-11 | 株式会社豊田自動織機製作所 | Capacity control structure for clutchless variable displacement compressor |
-
1996
- 1996-06-07 JP JP14576596A patent/JP3214354B2/en not_active Expired - Fee Related
-
1997
- 1997-06-04 KR KR1019970024049A patent/KR100235510B1/en not_active IP Right Cessation
- 1997-06-06 EP EP97109232A patent/EP0812987A3/en not_active Withdrawn
- 1997-06-06 CN CN 97114956 patent/CN1116564C/en not_active Expired - Fee Related
- 1997-06-06 CA CA 2207257 patent/CA2207257A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| CN1116564C (en) | 2003-07-30 |
| EP0812987A2 (en) | 1997-12-17 |
| EP0812987A3 (en) | 1999-06-02 |
| KR100235510B1 (en) | 1999-12-15 |
| JPH09324752A (en) | 1997-12-16 |
| JP3214354B2 (en) | 2001-10-02 |
| CN1182194A (en) | 1998-05-20 |
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| EEER | Examination request | ||
| FZDE | Dead |