WO2005008069A1

WO2005008069A1 - Compressor

Info

Publication number: WO2005008069A1
Application number: PCT/JP2004/010429
Authority: WO
Inventors: Katsumi Uehara; Shinichiro Higashihara
Original assignee: Calsonic Kansei Corporation
Priority date: 2003-07-22
Filing date: 2004-07-15
Publication date: 2005-01-27
Also published as: EP1618305A1; JP2005042624A

Abstract

A compressor includes a cylinder block having a cylinder bore. The compressor includes a front housing joined to a front end of the cylinder block and having a crank chamber. The compressor includes a rear housing joined to a rear end of the cylinder block via a valve plate and having a suction chamber and a discharge chamber. The compressor includes a piston configured to reciprocate in response to rotation of a drive shaft rotatably supported in the crank chamber. The suction chamber includes a first suction chamber in fluid communication with a suction port for introducing a refrigerant from outside. The suction chamber includes a second suction chamber in fluid communication with the cylinder bore through the valve plate. The first and second suction chambers are separated by a partition and communicate with each other through communication passages defined by the partition.

Description

DESCRIPTION COMPRESSOR

Technical Field The present invention relates to a compressor which performs adiabatic compression on refrigerant evaporated in¹ a refrigerating cycle for a vehicle.

Background Art An air conditioning apparatus for a vehicle includes a compressor in a refrigerating cycle, which adiabatically compresses refrigerant evaporated in the refrigerating cycle (for example, refer to Japanese Patent Application Laid-Open No. H6-317249). The compressor includes a cylinder block havingbores arranged. The compressor includes a cylinderhead which closes the outer end of the cylinder block while clamping a valve plate having a suction port and a discharge port corresponding to each of the bores . The compressor has pistons inserted and fitted in the respective bores, the pistons reciprocating with a predetermined phase difference. The compressor has a discharge chamber defined at a central region of the cylinder head and a suction chamber defined at an outer peripheral region of the discharge chamber. The compressor further includes a suction flange connected to a refrigerating circuit. The suction flange directly communicates with a plurality of regions inside the suction chamber through suction holes and leading holes . This structure reduces pressure loss inside the suction chamber, allowing a pressure difference of sucked refrigerant gas to be symmetrical.

Disclosure of Invention The compressor of a reciprocating type causes pressure pulsation in a refrigerant during reciprocation of the piston. As the number of revolutions of the compressor varies according to the number of revolutions of an engine, the frequency of the pressure pulsation also varies according to the number of revolutions ofthecompressor. Thenaturalvibrationfrequency of the compressor is relatively close to the natural vibration frequency of an auxiliary machine constituting the refrigerating cycle. When the number of revolutions of the compressor approaches a certain number of revolutions, the compressor and the auxiliary machine resonate with each other due to pressure pulsation of the refrigerant, thus generating abnormal noise. As a result, when refrigerant is sucked in the compressor, the pressure pulsation acts as a suction resistance, which results in reduction in suction efficiency. The present invention is directed to a compressor which allows for reduction in pressure pulsation and for reduction in generation of abnormal noise, thus preventing suction efficiency from lowering. The first aspect of the invention provides the following compressor. The compressor includes a cylinder block having a cylinderbore. The compressor includes afront housing joined to a front end of the cylinder block and having a crank chamber. The compressor includes a rear housing joined to a rear end of the cylinder block via a valve plate and having a suction chamber and a discharge chamber. The compressor includes a piston configured to reciprocate in response to rotation of a drive shaft rotatably supported in the crank chamber. The suction chamber includes a first suction chamber in fluid communication with a suction port for introducing a refrigerant from outside. The suction chamber includes a second suction chamber in fluid communication with the cylinder bore through the valve plate. The first and second suction chambers are separatedbyapartition andcommunicate with each other through communication passages defined by the partition. One of the communication passages may be positioned in front of an outlet of the suction port . The valve plate may have a suction hole and a valve mechanism defining a chalk with each other. The communication passages have a total flow-passage sectional area larger than a flow-passage sectional area of the chalk. The first chamber may have a substantially cylindrical shape. The second chamber is located annularly outside of the first chamber, with the partition interposed the first chamber and the second chamber. The first chamber and the valve plate have therebetween a substantially cylindrical discharge chamber located inside of the second suction chamber. The suctionchamberandthedischargechambermaybeformed of separated members respectively. The first and second suction chambers may have internal capacities different from each other. The partition may include a first wall defining a suction port passage in fluid communication with the suction port and the suction chamber. The partition may include a second wall defining a discharge port passage in fluid communication with the discharge port and the discharge chamber. The second aspect of the invention provides a vehicle air-conditioning compressor. The compressor includes a piston cylinder configured to suck refrigerant to compress the refrigerant to be displaced to a condenser. The compressor includes a piston cover in fluid communication with the piston cylinder. The piston cover includes a suction chamber configured to introduce refrigerant from an evaporator to the piston cylinder. The piston cover includes a capacitive chamber enclosed radially by the suction chamber and being in fluid communication with the suction chamber. The evaporator and the suction chamber may communicate with each other through the capacitive chamber. The piston cover may have a discharge chamber located radially inside of the suction chamber and axially with the capacitive chamber. The capacitive chamber is different from the suction chamber in capacity.

Brief Description of Drawings Fig.1 is a schematic diagramof anair conditioning system according to a first embodiment; Fig. 2 is a sectional view of a whole compressor shown in Fig. 1; Fig. 3 is a sectional view of a rear housing taken along line III-III in Fig. 2; Fig. 4 is a sectional view of a rear housing of a second embodiment as taken along the identical direction as in Fig. 2; Fig. 5 is a sectional view of a rear housing of a third embodiment as taken along the identical direction as in Fig. 2; Fig. 6 is a sectional view of a rear housing of a fourth embodiment as taken along the identical direction as in Fig. 2; and Fig.7 is a sectional view of the rear housing taken along line VII-VII in Fig. 6.

Best Mode for Carrying Out the Invention The following describes embodiments of a compressor according to the present invention with reference to the accompanying drawings. Like parts are designated by like reference numerals, and the explanations thereof are omitted. Referring to Fig. 1, an air-conditioning system for a vehicle 100 includes a compressor 1 outside a passenger compartment PI and a condenser 101 downstream of the compressor 1. The system 100 includes an air-conditioning unit 103 inside the passenger compartment Pi. The air-conditioning unit 103 includes a throttle 104, an evaporator 105, a heater 107, and a blower unit 109. The compressor 1, the condenser 101, the throttle 104, or the evaporator 105 has refrigerant Rl, R2 , or R3 circulating through the apparatus. The compressor 1 serves as a swash-plate variable displacement. The compressor 1 adiabatically compresses refrigerant evaporated in a refrigerating cycle of the air-conditioning system for a vehicle 100. Referring to Fig.2, the compressor 1 includes a cylinder block 2 having 6-cylindered bores 3 arranged about a driving shaft SI in a circumferential direction at equal intervals. The compressor 1 includes a front housing 4 joined to the front end face of the cylinder block 2. The compressor 1 has a rear housing 6A as a piston cover joined to the rear end face of the cylinder block 2 via a valve plate 9. The rear housing 6A has a suction chamber 7 and a discharge chamber 8. The cylinder block 2 , the front housing 4 , and the rear housing 6A are fastened and fixed with a plurality of through bolts Bl . The compressor 1 includes a power transmission mechanism 50 rotatably supported on the front housing 4 about the driving shaft SI. The valve plate 9 has suction holes 11 which permit each cylinder bore 3 and the suction chamber 7A to communicate with each other. The valve plate 9 has discharge holes 12 which permit each cylinder bore 3 and the discharge chamber 8 to communicate with each other. The valve plate 9 has a suction lead valve 14 which opens or closes the suctionhole 11 providedon the side of the cylinder block 2 and which serves as a valve mechanism. The valve plate 9 has adischarge leadvalve 15whichopens orcloses thedischarge hole 12 on the side of the rear housing 6A. The valve plate 9 and the rearhousing 6Ahave a gasket therebetween. The gasket maintains sealing between the suction chamber 7 and the discharge chamber 8. The valve plate 9 has joining faces at peripheral edges, with O-rings retained between one of the joining faces and the rear housing 6A and between the other of the joining faces andthe cylinderblock 2 , therebypreventing refrigerant from leakage outside the compressor 1. The cylinder block 2 and the front housing 4 have supporting holes 19, 20 at their centers, where driving shaft SI is rotatably supported, using bearings. A crank chamber 5 has a drive plate 21 fixed to the driving shaft SI inside thereof. The crank chamber 5 has a journal 24 slidably coupled to a sleeve 22 using a pin 23, with the sleeve 22 being slidably fitted to the driving shaft SI. The crank chamber 5 has a wobble plate or a swash plate 26 mounted on a boss 25 of the journal 24 using a bearing. The wobble plate 26 is slidably coupled to a restricting plate 35 fixedinside the crankchamber 5. The couplingprevents rotation of the wobble plate 26, while allows swinging thereof in an axial direction. When rotation of the driving shaft SI allows rotation of the journal 24, the wobble plate 26 is swung in the axial direction according to rotational swinging of the journal 24 without rotating. A drive plate 21 and the journal 24 have hinge arms 21h, 24h, respectively. The hinge arm 21h has an arc-shaped elongated hole 27. The hinge arm 24h has a pin 28 in engagement with the elongated hole 27. The engagement of the elongated hole 27 and the pin 28 couples the hinge arms 21h and 24h to each other. The coupling restricts the maximum inclination angle and the minimum inclination angle of the wobble plate 26. The cylinder bores 3 have pistons 29 received therein, respectively. The pistons 29 are each coupled to the wobble plate 26 using a piston rod 30. With the coupling, swinging of the wobble plate 26 allows reciprocatingmotion of the piston rod 30. The compressor 1A has basic function that the reciprocating motion of the piston 29 compresses refrigerant sucked in the order of the suction chamber 7 , the suction hole 11 of the valve plate 9, and the cylinder bore 3. The reciprocating motion discharges refrigerant compressed in the order of the cylinder bore 3, the discharge hole 12 of the valve plate 9 , and the discharge chamber 8. The compressor 1 includes a pressure control mechanism for making the discharge capacity variable. The pressure controlmechanism includes a gas extracting passage (not shown) which always brings the crank chamber 5 and the suction chamber 7 in fluid communication with each other. The pressure control mechanism includes a gas intake passage 32 which brings the crank chamber 5 and the discharge chamber 8 in fluid communication with each other. The pressure control mechanism includes an electromagnetic control valve (not shown) serving as a pressure control valve for opening or closing the gas intake passage 32. Opening or closing of the control valve supplies a high pressure refrigerant contained in the discharge chamber 8 to the crank chamber 5. Change of pressure in the crank chamber 5 changes an inclination angle of the wobble plate 26 due to pressure balance between the crank chamber 5 and the suction chamber 7 (a difference or a balance between pressures before and after the piston 29) . That is, change of a piston stroke changes the discharge capacity of the compressor 1. The power transmission mechanism 50 includes a pulley 51 rotatably supported to the driving shaft SI using a bearing 57. The pulley 51 is rotated according to rotations of a pulley of the engine using a belt. The power transmission mechanism 50 includes a drive plate 52 fixed to the outer peripheral edge of the pulley 51. The power transmission mechanism 50 includes a hub 53 fixed to the driving shaft SI using a bolt B2 and a washer. The power transmission mechanism 50 includes a transmission plate 54 connecting the hub 53 and the drive plate 52. Referringto Fig.3, the following specificallydescribes structure of the rear housing 6A. The rear housing 6A includes a suction port 16A to which the refrigerant Rl is supplied from an external piping (not shown) in fluid communication with the evaporator. The rear housing 6A as a refrigerant chamber has a first suction chamber 7al as a capacity chamber, which communicates with the suction port 16A in fluid communication with the evaporator 105. The first suction chamber 7al in an approximately cylindrical shape has an annular shape along the outer peripheral portion of the circumferential portion. The rear housing 6A has a second suction chamber 7bl in fluid communication with the cylinder bore 3 through the valve plate 9. The annular second suction chamber 7bl is disposed radially outside of the first suction chamber 7al , surrounding the first suction chamber 7al . The first and second suction chambers 7al and 7bl have a partition wall 10A arranged therebetween. The partition wall 10A defines three communication passages 13A at equal angular intervals , through which the first suction chamber 7al and the second suction chamber 7bl are in fluid communication with each other. In Fig. 2, the rear housing 6A has an approximately cylindrical discharge chamber 8A between the first suction chamber 7al and the valve plate 9 in the axial direction and on the inner peripheral portion (inside) of the second suction chamber 7bl in a radial direction. The discharge chamber 8A supplies compressed refrigerant to an external piping through the discharge port 17A, with the external piping being in fluid communication with the condenser. Further, the rear housing 6A includes a suction chambermember 6al and a discharge chamber member 6bl. The discharge chamber member 6bl is assembled inside the suction chamber member 6al. The suction chamber member 6al defines the first suction chamber 7al and the second suction chamber 7bl . The discharge chamber member 6bl defines the discharge chamber 8A. The suction chamber member 6al defines the first suction chamber 7al and the second suction chamber 7bl which have different inner capacities, respectively. The partition wall 10A defines one of the three communication passages 13 positioned at the front face of an outlet of the suction port 16A. The valve plate 9 has one suction hole of the suction holes 11 under a suction stroke, and the suction lead valve 14. The suction hole 11 and the lead valve 14 define a choke Cl therebetween. The communication passages 13A has a total flow-passage sectional area than a flow-passage sectional area of the choke Cl as a passage. Next, the following describes operation of the air-conditioning system 100. In Fig. 1, under cooling, the refrigerant Rl flows in the compressor 1, where the refrigerant is adiabatically compressed to be discharged as the refrigerant R2 therefrom. The refrigerant R2 flows into the condenser 101, where the refrigerant is isobarically cooled to be discharged as the refrigerant R3. The refrigerant R3 is isoenthalpically expanded by the throttle 104, and flows into the evaporator 105, where the refrigerant is heated and evaporated. At this time, air Al in the passenger compartment PI is suctioned into the blower unit 109, where the air exchanges heat with the refrigerant, being cooled. The air is discharged from the blower unit 109 to the passenger compartment PI as air A2. On the other hand, under heating, the air Al exchanges heat with the heater core 107, being heated. The air is discharged from the blower unit 109 to the passenger compartment PI as air A2. The following further describes operation of the compressor 1. In Fig.2, the reciprocatingmotion of the piston 29 sucks refrigerant to the suction chambers 7al and 7a2, the suction hole 11 of the valve plate 9, and the cylinder bore 3 to compress the refrigerant . The reciprocating motion discharges the compressed refrigerant through the cylinder bore 3, the discharge hole 12 of thevalve plate 9 , and the discharge chamber 8A. More specifically, rotation of the pulley of the engine allows the pulley 51 to be rotated. The rotation of the pulley 51 rotates the driving shaft SI. Rotation of the journal 21 on the driving shaft SI swings the wobble plate 26 in the axial direction. The swinging of the wobble plate 26 reciprocates the piston 29 in the axial direction using the piston rod 30. On the other hand, opening or closing of the control valve supplies high pressure refrigerant contained in the discharge chamber 8 to the crank chamber 5 through the passage 32. Change of the pressure in the crank chamber 5 changes the inclination angle of the wobble plate 26 due to pressure balance between the crank chamber 5 and the suction chamber 7bl (a difference or a balance between pressures before and behind the piston 29). In Fig. 3, the refrigerant Rl is supplied from the evaporator to the first suction chamber 7al through the suction port 16A. The refrigerant expands in the first suction chamber 7al to be fed to the second suction chamber 7bl through the communication passages 13A. Here, the refrigerant is accelerated temporarily while passing through the communication passages 13A. The refrigerant is supplied to the second suction chamber 7bl to expand therein again, which reduces a flow rate thereof. At this time, expansion and flow rate rise of the refrigerant reduces the pressure pulsation of the refrigerant during middle and low speed operation of the compressor 1. Next, under a suction stroke in the cylinder, while the piston 29 is moving from the top dead center to the bottom dead center, the cylinder has minus pressure inside thereof. The suction lead valve 14 opens the suction hole 11 according to the magnitude of the minus pressure. At this time, the refrigerant enters the cylinder from the second suction chamber 7bl through the opened suction hole 11. The piston 29 reaches the bottom dead center to transfer to a compression stroke. When the pressure of the refrigerant in the cylinder increases to exceed a predetermined pressure value, the discharge lead valve 15 opens. The high pressure refrigerant flows from the cylinder into the discharge chamber 8A, being supplied to the condenser 101 through the discharge port 17A and the external piping. Accordingto this embodiment , the first andsecondsuction chambers 7al and 7bl of the rear housing 6A are brought in fluid communication with each other through the communication passages 13A. The refrigerant, supplied into the compressor 1 , expands in the first suctionchamber 7al andthe secondsuction chamber 7bl with predetermined capacities respectively. The expansionreduces pressure pulsation generated during a middle rotation operation of the compressor 1. While the refrigerant is passing through the communication passages 13 with the predetermined sectional area, the flow rate rises. The rise in flow rate reduces pressure pulsation generated during a low rotation operation of the compressor 1. This reduces production of abnormal noise in a wide range from the low rotation range to a middle rotation range of the compressor 1, which particularly irritates a passenger, and prevents reduction in suction efficiency. The refrigerant is introduced from the suction port 16A into the first suction chamber 7al , being linearly introduced into the second suction chamber 7bl through the communication passages 13A. This reduces ventilation resistance from the suction port 16A to the suction hole 11 located far therefrom, further preventing lowering of the suction resistance. The suction hole 11 in the suction stroke and the suction lead valve 14 provided in the valve plate 9 define the choke Cl. The total sectional area of the communication passages 13A becomes larger than the sectional area of the passage of the choke Cl . The communication passages 13A do not act as suction resistance, which reduces production of abnormal noise during a low rotation range. The rear housing 6A has the suction chamber 7A with an internal capacityrequired toreducepressurepulsationwithout increasing radial size of the whole apparatus . The formation of the suction chamber 7A and the discharge chamber 8A with different members simplifies manufacturing steps for the rear housing 6A, reducing production cost. The provision of the first suction chamber 7al and the second suction chamber 7bl with different internal capacities respectively changes a frequency range of pressure pulsation to be cancelled. This reduces production of abnormal noise over a further wide rotation range.

Second Embodiment Referring to Figs . 4 , a compressor IB includes a rear housing 6B, which is different from that of the first embodiment in the structure. The rear housing 6B is different from the rear housing 6A in that a suction port 16B is in fluid communication with a second suction chamber 7b2 insteadof the first suction chamber 7a2. The suction port 16B has refrigerant to be supplied from an external piping (not shown) . One of the three communication passages 13B is positioned on a partition wall 10B in front of an outlet of the suction port 16B. The refrigerant Rl is supplied from the suction port 16B to the second suction chamber 7b2. Aportion of the refrigerant flows into the first suction chamber 7a2 through the communication passage 13B in front of the suction port 16B for expansion. The portion of refrigerant flows into the second suction chamber 7b2 through another communication passages 13B again, where the refrigerant accelerates temporarily while passing through the communication passages 13B. The portion of refrigerant is supplied to the second suction chamber 7b2, thus expanding again. This lowers a flow rate thereof.

Third Embodiment Referring to Fig.5, a compressor 1C include arearhousing 6C, which is different from that of the first embodiment in structure. The rear housing 6C has a muffler chamber 18C serving as a capacitor and having a predetermined capacity outside a suction chamber member 6a3. The muffler chamber 18C has a suction port 16C supplied with refrigerant from an external piping (not shown) . The muffler chamber 18C is in fluid communication with a first suction chamber 7a3 through a communication passage 13a3. The communication passage 13a3 is definedbythe suction chambermember 6a3 withapredetermined sectional area. The muffler chamber 18C, the first suction chamber 7a3 , and a second suction chamber 7b3 have different internal capacities, respectively. The refrigerant Rl is supplied from the suction port 16C to the muffler chamber 18C. The refrigerant expands in the mufflerchamber 18C tobe suppliedinto the first suction chamber 7a3 through the communication passage 13a3. The refrigerant expands in the first suction chamber 7a3 to be fed into the second suction chamber 7b3 through communication passages 13C. Here, the refrigerant accelerates temporarily while passing through the communication passage 13a3 and the communication passages 13C. When the refrigerant is supplied to the first suction chamber 7a3 and the second suction chamber 7b3 , the refrigerant expands again, which lowers flow rate. According to this embodiment, the muffler chamber 18C and the first suction chamber 7a3 of the rear housing 6C are influidcommunicationwitheachotherthroughthe communication passage 13a3. The first suction chamber 7a3 and the second suction chamber 7b3 are in fluid communication with each other throughthecommunicationpassages 13C. This structurereduces pressurepulsation generatedduring amiddle rotation operation of the compressor 1C, while the refrigerant, supplied into the compressor 1C, expands in the muffler chamber 18C, the first suction chamber 7a3, and the second suction chamber 7b3 with thepredeterminedcapacities . The structure increases theflow rate of the refrigerant, while the refrigerant is passing through the communication passages 13a3 and 13C with the predetermined sectional areas. This reduces pressure pulsation, which is generated during a low rotation operation of the compressor 1C. The first suction chamber 7a3 , the second suction chamber 7b3 , and the muffler chamber 18C are respectively providedwith different internal capacities. This changes the frequency range of the pressure pulsation to be cancelled, which reduces production of abnormal noise over a furtherwide rotation range. Fourth Embodiment Referring to Figs. 6 and 7, a compressor ID has a rear housing 6D, which is different from that of the first embodiment in structure. The rear housing 6D has a suction port passage 16a4, which allows a suction port 16D and a suction chamber 7D to fluid communicate with each other. The passage 16a4 is defined by a wall 16b4. The rear housing 6D has a discharge port passage 17a4, which allows the discharge port 17D and the discharge chamber 8A to fluid communicate with each other. The passage 17a4 is defined by a wall 17b4. The rear housing 6D includes a mounting bolt seat 6d4 formed in a suction chamber member 6a4. Mounting bolt seats 6d4, 6d5 and 6d6 are used to fix a discharge chamber member 6b4 to the suction chamber member 6a4 by a bolt 6c. The rear housing 6D has a valve accommodating chamber (not shown), which accommodates an electromagnetic control valve (not shown) and is defined by walls . A partition wall 10D is defined by walls 16b4 and 17b4, and the walls of the valve accommodating chamber. That is, the wall faces 16b4 and 17b4 define a communication passage 13D1 therebetween. The mounting bolt seats 6d4 and 6d5 define a communication passage 13D2 therebetween. The mounting bolt seats 6d5 and 6d6 define a communication passage 13D3 therebetween. Accordingto this embodiment , therearhousing 6D includes the wall face 16b4 defining the suction port passage 16a4, the wall face 17b4 defining the discharge port passage 17a4, the three mounting bolt seats 6d4, 6d5, 6d6, and the valve accommodating chamber. The walls 16b4 and 17b4, mounting bolt seat 6d4, and valve accommodating chamber constitute the partition wall 10D. This structure has the suction chamber 7D provided with a necessary internal capacity without increasing the entire compressor in size. Although the invention has been described above by reference to certainembodiments of theinvention, the invention is not limited to the embodiments described above. Modifications andvariations of the embodiments describedabove will occur to those skilled in the art, in light of the above teachings . The scope of the invention is definedwithreference to the following claims .

Industrial Applicability The compressor of invention is adapted to an air conditioner for a vehicle, and reduces pressure pulsation with stable operation.

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2003-277856 filed on July 22, 2003; the entire contents of which are incorporated herein by reference.

Claims

1. A compressor comprising: a cylinder block having a cylinder bore; a front housing joined to a front end of the cylinder block and having a crank chamber; a rear housing joined to a rear end of the cylinder block via a valve plate and having a suction chamber and a discharge chamber; and apistonconfiguredtoreciprocate inresponse to rotation of a drive shaft rotatably supported in the crank chamber, wherein the suction chamber comprising: a first suction chamber in fluid communication with a suction port for introducing a refrigerant from outside; and a second suction chamber in fluid communication with the cylinder bore through the valve plate, wherein the first and second suction chambers are separatedby apartition andcommunicatewitheach other through communication passages defined by the partition.

2. The compressor according to 1, wherein one of the communication passages is positioned in front of an outlet of the suction port.

3. The compressor according to claim 1, wherein the valve plate has a suction hole and a valve mechanism defining a chalk with each other. wherein the communication passages have a total flow- passage sectional area larger than a flow-passage sectional area of the chalk.

4. The compressor according to claim 1, wherein the first chamberhas a substantiallycylindrical shape, wherein the second chamber is located annularly outside of the first chamber, with the partition interposed the first chamber and the second chamber, wherein the first chamber and the valve plate have therebetween a substantially cylindrical discharge chamber located inside of the second suction chamber.

5. The compressor according to claim 4, wherein the suction chamber and the discharge chamber are formed of separated members respectively.

6. The compressor according to claim 1, wherein the first and second suction chambers have internal capacities different from each other.

7. The compressor according to claim 1, wherein the partition comprises : a first wall defining a suction port passage in fluid communication with the suction port and the suction chamber; and a second wall defining a discharge port passage in fluidcommunicationwith the discharge port and the discharge chamber.

8. A vehicle air-conditioning compressor comprising: a piston cylinder configured to suck refrigerant to compress the refrigerant to be displaced to a condenser; and a piston cover in fluid communication with the piston cylinder, the piston cover comprising: a suction chamber configured to introduce refrigerant from an evaporator to the piston cylinder ; and a capacitive chamber enclosed radially by the suction chamber and being in fluid communication with the suction chamber.

9. The vehicle air-conditioning compressor according to claim 8, wherein the evaporator and the suction chamber communicate with each other through the capacitive chamber.

10. The vehicle air-conditioning compressor according to claim 8, wherein the piston cover has a discharge chamber located radially inside of the suction chamber and axially with the capacitive chamber.

11. The vehicle air-conditioning compressor according to claim 8, wherein the capacitive chamber is different from the suction chamber in capacity.