EP1433956B1 - Scroll compressor - Google Patents
Scroll compressor Download PDFInfo
- Publication number
- EP1433956B1 EP1433956B1 EP03029176A EP03029176A EP1433956B1 EP 1433956 B1 EP1433956 B1 EP 1433956B1 EP 03029176 A EP03029176 A EP 03029176A EP 03029176 A EP03029176 A EP 03029176A EP 1433956 B1 EP1433956 B1 EP 1433956B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- scroll member
- chamber
- movable scroll
- back pressure
- pressure chamber
- 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.)
- Expired - Lifetime
Links
- 230000006835 compression Effects 0.000 claims description 48
- 238000007906 compression Methods 0.000 claims description 48
- 239000003507 refrigerant Substances 0.000 claims description 45
- 238000007789 sealing Methods 0.000 claims description 15
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 14
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 7
- 239000001569 carbon dioxide Substances 0.000 claims description 7
- 238000005057 refrigeration Methods 0.000 claims description 7
- 230000001105 regulatory effect Effects 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000013459 approach Methods 0.000 description 3
- 230000000903 blocking effect Effects 0.000 description 3
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 3
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- 235000014676 Phragmites communis Nutrition 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000004512 die casting Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C27/00—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids
- F04C27/005—Axial sealings for working fluid
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
- F04C23/008—Hermetic pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2210/00—Fluid
- F04C2210/26—Refrigerants with particular properties, e.g. HFC-134a
- F04C2210/261—Carbon dioxide (CO2)
Definitions
- the present invention relates to a scroll compressor as defined in the preamble of claim 1.
- a scroll compressor is known from US-A-6 086 342 .
- the scroll compressor is part of a refrigeration cycle in a vehicle air conditioner for compressing refrigerant.
- a scroll compressor of such type includes a fixed scroll member and a movable scroll member.
- the fixed scroll member has a spiral wall and a base plate, and is fixedly connected to a housing of the compressor.
- the movable scroll member has a spiral wall and a base plate, and is engaged with the spiral wall of the fixed scroll member. As the movable scroll member orbits, compression chambers defined between both the spiral walls progressively reduce in volume, thus compressing refrigerant gas.
- the back surface of the movable scroll member is recessed to form a pocket for applying back pressure, and the pocket for applying back pressure is shut by a fixed wall provided in a housing of the compressor.
- a back pressure chamber is formed.
- a volume-reducing compression chamber communicates with the back pressure chamber through an introducing passage. Accordingly, force (force based upon the back pressure) that resists against force (thrust load) based upon pressure in the compression chambers is applied to the movable scroll member due to the pressure in the back pressure chamber, so that sliding resistance is reduced between the movable scroll member and the fixed wall. Additionally, the movable scroll member is pressed against the fixed scroll member, so that sealing performance of the compression chambers improve.
- the pressure in the back pressure chamber is appropriately adjusted by variation in the amount of a clearance (passing cross-sectional area) between the movable scroll member and the fixed scroll wall.
- a clearance passing cross-sectional area
- the clearance between the movable scroll member and the fixed wall increases. Accordingly, the amount of refrigerant gas delivered from the back pressure chamber to a relatively low pressure region through the clearance increases, so that an excessive rise in the pressure in the back pressure chamber is prevented.
- the clearance between the movable scroll member and the fixed wall reduces. Accordingly, the amount of refrigerant gas delivered from the back pressure chamber to the relatively low pressure region through the clearance reduces, so that undesirable reduction in the pressure in the back pressure chamber is prevented.
- the pressure in the back pressure chamber is adjusted in a much higher range than that when fluorocarbon refrigerant is employed. Accordingly, in order to appropriately adjust the pressure in the back pressure chamber, the clearance between the movable scroll member and the fixed wall need be much narrower at the maximum. Thus, a rise in cost for manufacturing becomes a further serious problem. Therefore, there is a need for providing a scroll compressor that has a reasonable structure and optionally and appropriately adjusts pressure in a back pressure chamber.
- the scroll compressor comprises a fixed scroll member and an orbiting scroll member engaged with the fixed scroll member, wherein a compression chamber is formed therein between for reducing in volume by orbiting the scroll members relative to each other.
- the compressor discloses a back pressure chamber for forcing the movable scroll member relative to the fixed scroll member, and seal members for sealing the back pressure chamber as well as for enabling a slidable movement of the movable scroll member relative to the housing.
- a scroll compressor according to the present invention is applied to an electric compressor for use in a refrigeration cycle of a vehicle air conditioner.
- carbon dioxide is employed as refrigerant of the refrigeration cycle.
- the left side and the right side of FIG. 1 respectively correspond to the front side and the rear side of the electric compressor.
- a housing 11 of the electric compressor includes a first housing element 21 and a second housing element 22.
- the first housing element 21 and the second housing element 22 are fixedly connected with each other.
- the first housing element 21 has a cylindrical portion 23 and a bottom portion 24, which connects with the rear end of the cylindrical portion 23 (on the right side of FIG. 1 ).
- the first housing element 21 forms a cylinder with a bottom at one end and is formed by die-casting an aluminum alloy.
- the second housing element 22 forms a cylinder with a bottom on the front side (the left side of FIG. 1 ) and is formed by die-casting an aluminum alloy.
- a cylindrical shaft support portion 24a extends from the center of an inner wall surface of the bottom portion 24 in the first housing element 21.
- a shaft support member 32 which has an insertion hole 32a formed through the center thereof, is fixedly connected to an opening end of the cylindrical portion 23 in the first housing element 21.
- a rotary shaft 33 is accommodated in the first housing element 21. The rear end (the right end) of the rotary shaft 33 is rotatably supported by the shaft support portion 24a of the first housing element 21 through a bearing 34. The front end (the left side) of the rotary shaft 33 is inserted through the insertion hole 32a of the shaft support member 32, and is rotatably supported by the shaft support member 32 through a bearing 35 in the insertion hole 32a.
- a motor chamber 12 is defined in the housing 11 and is located on the rear side of FIG. 1 relative to the shaft support member 32.
- a stator 36 is provided on the inner circumferential surface of the cylindrical portion 23 of the first housing element 21.
- a rotor 37 is secured to the rotary shaft 33 so as to be located inside the stator 36.
- the stator 36 and the rotor 37 constitute the electric motor 13.
- the electric motor 13 integrally rotates the rotor 37 and the rotary shaft 33 by electric power externally supplied to the stator 36.
- a fixed scroll member 41 is accommodated in the first housing element 21 and is located near the opening end of the cylindrical portion 23.
- the fixed scroll member 41 includes a disc-shaped base plate 61, a cylindrical outer circumferential wall 62 and a spiral wall 63.
- the outer circumferential wall 62 extends from the outer periphery of the base plate 61.
- the spiral wall 63 extends from the base plate 61 and is located inside the outer circumferential wall 62.
- a disc-shaped center frame or a fixed wall 31 is arranged between the fixed scroll member 41 and the shaft support member 32.
- a through hole 31 a is formed through the center of the center frame 31.
- An annular contact portion 31 b is located at the opening end near the motor chamber 12 in the through hole 31 a and protrudes inward.
- the fixed scroll member 41 is connected to the outer periphery of the center frame 31 by the distal end surface of the outer circumferential wall 62.
- An annular shim 68 is interposed at a joint between the fixed scroll member 41 and the center frame 31.
- the base plate 61 of the fixed scroll member 41, the outer circumferential wall 62 of the fixed scroll member 41 and the center frame 31 surround to define a scroll chamber 15 in the housing 11.
- a crankshaft 43 is provided at the end surface of the rotary shaft 33 near the center frame 31.
- the crankshaft 43 is mostly arranged in the through hole 31 a of the center frame 31.
- a bushing 44 is fixedly fitted around the crankshaft 43.
- a movable scroll member 45 is accommodated in the scroll chamber 15 and is rotatably supported on the bushing 44 through a bearing 46 so as to face the fixed scroll member 41.
- a balancer 44a is provided at the end of the bushing 44 near the shaft support member 32.
- the balancer 44a relieves imbalance on the rotary shaft 33 due to uneven arrangement of the movable scroll member 45 around an axis L of the rotary shaft 33.
- the balancer 44a is accommodated in a balancer chamber 14 outside the through hole 31 a.
- the balancer chamber 14 is defined between the shaft support member 32 and the center frame 31.
- the balancer chamber 14 communicates with the motor chamber 12 through a clearance of the bearing 35. Accordingly, the balancer chamber 14 has the same atmospheric pressure as that of the motor chamber 12.
- the movable scroll member 45 includes a disc-shaped base plate 65 and a spiral wall 66 that extends toward the fixed scroll member 41.
- a boss 67 is provided near the center of a back surface of the base plate 65 and protrudes therefrom.
- the boss 67 is fitted around the bushing 44 through the bearing 46 in the through hole 31 a of the center frame 31.
- An annular tip seal 77 is provided at the distal end of the boss 67.
- the boss 67 slidably contacts with the contact portion 31 b of the center frame 31 by the tip seal 77. Accordingly, in the through hole 31 a, the tip seal 77 blocks communication between an inner space of the boss 67 communicating with the balancer chamber 14 and an outer space of the boss 67.
- the fixed scroll member 41 and the movable scroll member 45 engage with each other by the respective spiral walls 63, 66 in the scroll chamber 15, while the distal end of the spiral wall 63 and the distal end of the spiral wall 66 contact with the base plate 65 of the movable scroll member 45 and the base plate 61 of the fixed scroll member 41, respectively. Accordingly, the base plate 61 and the spiral wall 63 of the fixed scroll member 41 and the base plate 65 and the spiral wall 66 of the movable scroll member 45 define compression chambers 47 in the scroll chamber 15.
- a self-rotation blocking mechanism 48 is provided between the base plate 65 of the movable scroll member 45 and the center frame 31 facing the base plate 65.
- the self-rotation blocking mechanism 48 includes a plurality of cylindrical holes 48a and a plurality of pins 48b (only one of them is shown in FIG. 1 ).
- the cylindrical holes 48a are recessed in radially outer portions of the back surface 65a of the base plate 65 in the movable scroll member 45.
- the pins 48b are buried in an end surface 31 c of the center frame 31 and are loosely fitted therein.
- a suction chamber 51 is defined between the outer circumferential wall 62 of the fixed scroll member 41 and the outermost circumferential portion of the spiral wall 66 of the movable scroll member 45.
- a suction passage 39 is formed in radially outer portions of the shaft support member 32, the shim 68 and the center frame 31 for interconnecting the suction chamber 51 and the motor chamber 12.
- a suction port 50 is formed in the cylindrical portion 23 of the first housing element 21 and is located to correspond with the motor chamber 12.
- the suction port 50 connects with an external conduit, which further connects with an evaporator (not shown) of an external refrigerant circuit.
- the suction port 50 communicates with the motor chamber 12. Accordingly, relatively low pressure refrigerant gas from the external refrigerant circuit is introduced into the suction chamber 51 through the suction port 50, the motor chamber 12 and the suction passage 39.
- a discharge chamber 52 is defined between the second housing element 22 and the fixed scroll member 41.
- a discharge port 53 for communicating with the discharge chamber 52 is formed in the second housing element 22.
- the discharge port 53 connects with an external conduit, which further connects with a gas cooler (not shown) of the external refrigerant circuit. Accordingly, relatively high pressure refrigerant gas in the discharge chamber 52 is delivered to the external refrigerant circuit through the discharge port 53.
- a discharge hole 41 a is formed through the center of the base plate 61 of the fixed scroll member 41.
- the compression chamber 47 near the center communicates with the discharge chamber 52 through the discharge hole 41 a.
- a discharge valve 55 constituted of a reed valve is arranged on the base plate 61 of the fixed scroll member 41 for opening and closing the discharge hole 41 a.
- the opening degree of the discharge valve 55 is regulated by a retainer 56, which is fixedly arranged on the base plate 61 of the fixed scroll member 41.
- the movable scroll member 45 orbits around the axis (the axis L of the rotary shaft 33) of the fixed scroll member 41 through the crankshaft 43.
- the self-rotation of the movable scroll member 45 is blocked by the self-rotation blocking mechanism 48, so that only the orbital movement of the movable scroll member 45 is permitted.
- the compression chambers 47 reduce in volume as the compression chambers 47 move from the radially outer side of the spiral walls 63, 66 of the respective scroll members 41, 45 toward the center of the spiral walls 63, 66.
- relatively low pressure refrigerant gas introduced from the suction chamber 51 to the compression chambers 47 is compressed.
- the compressed refrigerant gas is discharged to the discharge chamber 52 through the discharge hole 41 a by pushing away the discharge valve 55.
- a back pressure chamber 16 is located on the side of the back surface 65a of the base plate 65 of the movable scroll member 45.
- the base plate 65 and the boss 67 of the movable scroll member 45 and the center frame 31 surround to define the back pressure chamber 16. Communication between the back pressure chamber 16 and the balancer chamber 14 is blocked by the tip seal 77, which is interposed between the boss 67 of the movable scroll member 45 and the contact portion 31 b of the center frame 31.
- annular groove 65b for accommodating a seal is recessed in radially outer portion relative to the cylindrical recesses 48a so as to surround the cylindrical recesses 48a.
- An annular seal member 75 constituted of a tip seal is fitted in the groove 65b.
- the back surface 65a of the movable scroll member 45 slidably and elastically contacts with an end surface 31c of the center frame 31 by the seal member 75. Namely, the seal member 75 is interposed at a clearance CL between the back surface 65a of the movable scroll member 45 and the end surface 31c of the center frame 31. Communication between the back pressure chamber 16 and the suction chamber 51 through the entire clearance CL is blocked by the seal member 75.
- a maximum distance of the clearance CL between the movable scroll member 45 and the center frame 31, that is, a thrust clearance between the movable scroll member 45 and the center frame 31, is adjusted in an appropriate distance in such a manner that a shim 68 having an appropriate thickness is selected from a plurality of shims 68 having different thicknesses and is assembled to the clearance CL when the electric compressor is manufactured.
- an introducing passage 76 is formed in the base plate 65 of the movable scroll member 45 so as to extend through the base plate 65 in thickness.
- Two introducing passages 76 are provided.
- the back pressure chamber 16 and a volume-reducing (compressing) compression chamber 47A which is a relatively high pressure region, are interconnected through one introducing passage 76.
- the back pressure chamber 16 and a volume-reducing compression chamber 47B which is different from the compression chamber 47A, are interconnected through the other introducing passage 76.
- the introducing passages 76 are symmetrically located in the base plate 65 from each other with an angle of 180 degrees with respect to the axis of the crankshaft 43, and respectively open to the corresponding compression chambers 47A, 47B.
- a fixed throttle 76a is arranged in each of the introducing passages 76.
- the back surface 65a of the base plate 65 forms two accommodating recesses 65c, with which the opening of each introducing passage 76 on the side of the back pressure chamber 16 communicates.
- a check valve 78 constituted of a reed valve is accommodated in each of the accommodating recesses 65c. The check valves 78 each permit refrigerant gas supplied from the compression chambers 47A, 47B to the back pressure chamber 16, and block the refrigerant gas returned from the back pressure chamber 16 to the compression chambers 47A, 47B.
- a portion 75a for lowering sealing performance (hereinafter, a seal lowering portion 75a) relative to the other portion is provided for the seal member 75.
- the seal lowering portion 75a is formed by splitting a portion of the annular seal member.
- the back pressure chamber 16 and the suction chamber 75 which is a relatively low pressure region, are interconnected through the seal lowering portion 75a of the seal member 75 in the clearance CL between the movable scroll member 45 and the center frame 31.
- dimensions of the seal lowering portion 75a (a split portion in the seal member 75) are exaggeratedly illustrated for easier understanding.
- the seal lowering portion 75a is formed by an extremely narrow clearance.
- a relatively high pressure region means a region where relatively high pressure refrigerant gas, which is compressed by the fixed scroll member 41 and the movable scroll member 45, exists
- a relatively low pressure region means a region where relatively low pressure refrigerant gas, which is yet to be compressed by the fixed scroll member 41 and the movable scroll member 45, exists.
- the check valve 78 opens so that the relatively high pressure refrigerant gas in the volume-reducing compression chambers 47A, 47B is introduced into the back pressure chamber 16 through the respective introducing passages 76. Accordingly, the pressure in the back pressure chamber 16 rises so that force (back pressure force) F1 urging the movable scroll member 45 toward the fixed scroll member 41 is applied based upon the pressure in the back pressure chamber 16.
- force (thrust load) F2 based upon the pressure in the compression chambers 47 is applied to the movable scroll member 45 toward a direction to leave the fixed scroll member 41. Accordingly, a position of the movable scroll member 45 relative to the center frame 31 is determined in accordance with a balance between the force F1 and the force F2.
- the passing cross-sectional area of refrigerant gas increases at the seal lowering portion 75a of the seal member 75. Accordingly, the amount of refrigerant gas delivered from the back pressure chamber 16 to the suction chamber 51 increases so that the pressure in the back pressure chamber 16 falls to reduce the force F1.
- the passing cross-sectional area of refrigerant gas reduces at the seal lowering portion 75a of the seal member 75. Accordingly, the amount of refrigerant gas delivered from the back pressure chamber 16 to the suction chamber 51 reduces so that the pressure in the back pressure chamber 16 rises to increase the force F1.
- the movable scroll member 45 varies the clearance CL (distance) between the back surface 65a and the end surface 31 c of the center frame 31 in such a manner that the force F1 based upon the pressure in the back pressure chamber 16 becomes an appropriate magnitude in a correspondence with the force F2 based upon the pressure in the compression chambers 47.
- the passing cross-sectional area of the seal lowering portion 75a is thereby autonomously adjusted.
- the adjustment of the pressure in the back pressure chamber 16 is predetermined in such a manner that a state, where the force F1 applied to the movable scroll member 45 slightly exceeds the force F2, is maintained for a relatively long time.
- the balancer chamber 14 is defined as a relatively low pressure region, while the tip seal 77 for separating the balancer chamber 14 from the back pressure chamber 16 is defined as a seal member. As shown in FIG. 4 , the tip seal 77 is partially split to form a seal lowering portion 77a for lowering sealing performance, and the back pressure chamber 16 and the balancer chamber 14 are interconnected through the seal lowering portion 77a.
- the movable scroll member 45 is displaced in a direction in which the distal end of the boss 67 approaches the contact portion 31 b of the center frame 31. Accordingly, a clearance between the distal end surface of the boss 67 and the contact portion 31 b of the center frame 31 reduces, so that the passing cross-sectional area for refrigerant gas reduces at the seal lowering portion 77a of the tip seal 77.
- the amount of refrigerant gas delivered from the back pressure chamber 16 to the balancer chamber 14 reduces, and the pressure in the back pressure chamber 16 rises to increase the force F1.
- the same advantageous effects such as appropriate adjustment of pressure in the back pressure chamber 16 with a relatively low-cost structure, are obtained.
- the back pressure chamber 16 and the balancer chamber 14 are interconnected not through the seal lowering portion 75a but through another passage 81.
- a differential pressure regulating valve 82 is arranged in the passage 81 for opening when differential pressure between the back pressure chamber 16 and the balancer chamber 14 is equal to or greater than a predetermined value.
- the differential pressure regulating valve 82 includes a spherical valve body 82a, a coil spring 82b and a spring seat 82c.
- the pressure in the back pressure chamber 16 and the pressure in the balancer chamber 14 are respectively applied to the front side and the rear side of the valve body 82a.
- the coil spring 82b urges the valve body 82a in a direction to close the valve.
- the passing cross-sectional area of the seal lowering portion 75a is adjusted in response to a balance between the force F1 based upon the pressure in the back pressure chamber 16 and the force F2 based upon the pressure in the compression chambers 47.
- the pressure in the back pressure chamber 16 is adjusted by utilizing two valves (the seal lowering portion 75a and the differential pressure regulating valve 82) each having different characteristic. Accordingly, a region where only one of the valves 75a and 82 cannot appropriately adjust pressure may be mutually covered by combination with the other of the valves 82 and 75a. Thus, the pressure in the back pressure chamber 16 is further appropriately adjusted.
- one portion of the annular seal member 75 is split to form the seal lowering portion 75a.
- a plurality of portions of a seal member such as two, three, four, five or six portions, is split to form portion for lowering sealing performance at plural portions of the seal member.
- the seal lowering portion 75a is formed by partially splitting the annular seal member 75.
- the annular shape of the seal member is maintained, while a groove is partially formed in the seal member.
- a seal lowering portion for lowering sealing performance is formed.
- two volume-reducing compression chambers 47A, 47B independently communicate with the back pressure chamber 16 through the respective introducing passages 76.
- two introducing passages 76 which respectively extend from two compression chambers 47A, 47B, are integrated on the way and the integrated one introducing passage communicates with the back pressure chamber 16.
- relatively high pressure refrigerant gas is introduced from the volume-reducing compression chambers 47A, 47B to the back pressure chamber 16.
- the compression chamber 47 near the center (the compression chamber 47 completes compression) or the discharge chamber 52 is defined as a relatively high pressure region, while the upstream portion of the introducing passage 76 communicates with the relatively high pressure region, so that the high pressure refrigerant gas, which is higher in pressure than the refrigerant gas in the volume-reducing compression chambers 47A, 47B, is introduced to the back pressure chamber 16.
- a scroll compressor is embodied as the electric compressor.
- the scroll compressor is not limited to the electric compressor.
- a scroll compressor driven by an engine of a vehicle, a hybrid type scroll compressor having an electric motor and an engine as drive sources, may be employed.
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Description
- The present invention relates to a scroll compressor as defined in the preamble of claim 1. Such a compressor is known from
US-A-6 086 342 . In particular the scroll compressor is part of a refrigeration cycle in a vehicle air conditioner for compressing refrigerant. - A scroll compressor of such type includes a fixed scroll member and a movable scroll member. The fixed scroll member has a spiral wall and a base plate, and is fixedly connected to a housing of the compressor. The movable scroll member has a spiral wall and a base plate, and is engaged with the spiral wall of the fixed scroll member. As the movable scroll member orbits, compression chambers defined between both the spiral walls progressively reduce in volume, thus compressing refrigerant gas.
- Recently, carbon dioxide is employed as refrigerant for the refrigeration cycle. When carbon dioxide refrigerant is employed, pressure in the refrigeration cycle becomes much higher than that when fluorocarbon refrigerant is employed. Accordingly, in the scroll compressor, relatively large thrust load based upon pressure in the compression chambers is applied to the movable scroll member. Thus, the movable scroll member slides under relatively hard condition, so that reliability of the scroll compressor is deteriorated.
- In order to solve such a problem, for example, as disclosed in Unexamined Japanese Patent Publication No.
2000-249086 - The pressure in the back pressure chamber is appropriately adjusted by variation in the amount of a clearance (passing cross-sectional area) between the movable scroll member and the fixed scroll wall. In other words, for example, as the pressure in the back pressure chamber rises, the clearance between the movable scroll member and the fixed wall increases. Accordingly, the amount of refrigerant gas delivered from the back pressure chamber to a relatively low pressure region through the clearance increases, so that an excessive rise in the pressure in the back pressure chamber is prevented. On the contrary, as the pressure in the back pressure chamber falls, the clearance between the movable scroll member and the fixed wall reduces. Accordingly, the amount of refrigerant gas delivered from the back pressure chamber to the relatively low pressure region through the clearance reduces, so that undesirable reduction in the pressure in the back pressure chamber is prevented.
- An unwanted feature is that in accordance with the Unexamined Japanese Patent Publication No.
2000-249086 - Particularly, when carbon dioxide refrigerant is employed, the pressure in the back pressure chamber is adjusted in a much higher range than that when fluorocarbon refrigerant is employed. Accordingly, in order to appropriately adjust the pressure in the back pressure chamber, the clearance between the movable scroll member and the fixed wall need be much narrower at the maximum. Thus, a rise in cost for manufacturing becomes a further serious problem. Therefore, there is a need for providing a scroll compressor that has a reasonable structure and optionally and appropriately adjusts pressure in a back pressure chamber.
- An additional example of a scroll compressor is known from
US-6,086,342 . In this document, the scroll compressor comprises a fixed scroll member and an orbiting scroll member engaged with the fixed scroll member, wherein a compression chamber is formed therein between for reducing in volume by orbiting the scroll members relative to each other. Furthermore, the compressor discloses a back pressure chamber for forcing the movable scroll member relative to the fixed scroll member, and seal members for sealing the back pressure chamber as well as for enabling a slidable movement of the movable scroll member relative to the housing. - The above mentioned problems are solved by a scroll compressor with the features according to claim 1.
- Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
- The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:
-
FIG. 1 is a longitudinal cross-sectional view of an electric compressor according to a preferred embodiment of the present invention; -
FIG. 2 is a rear end view of a movable scroll member, which is detached from the scroll compressor, according to the preferred embodiment of the present invention; -
FIG. 3A is a partially enlarged cross-sectional view around a seal member ofFIG. 1 ; -
FIG. 3B is a partially enlarged cross-sectional view illustrating a state when a passing cross-sectional area of a portion for lowering sealing performance becomes small; -
FIG. 4 is a rear end view of a movable scroll member according to an alternative embodiment of the present invention; and -
FIG. 5 is a partially enlarged cross-sectional view of a relevant portion of an electric compressor according to an alternative embodiment of the present invention. - A preferred embodiment of the present invention will now be described with reference to
FIGs. 1 through 3B . In the preferred embodiment, a scroll compressor according to the present invention is applied to an electric compressor for use in a refrigeration cycle of a vehicle air conditioner. Incidentally, carbon dioxide is employed as refrigerant of the refrigeration cycle. The left side and the right side ofFIG. 1 respectively correspond to the front side and the rear side of the electric compressor. - As shown in
FIG. 1 , ahousing 11 of the electric compressor includes afirst housing element 21 and asecond housing element 22. Thefirst housing element 21 and thesecond housing element 22 are fixedly connected with each other. Thefirst housing element 21 has acylindrical portion 23 and abottom portion 24, which connects with the rear end of the cylindrical portion 23 (on the right side ofFIG. 1 ). Thus, thefirst housing element 21 forms a cylinder with a bottom at one end and is formed by die-casting an aluminum alloy. Thesecond housing element 22 forms a cylinder with a bottom on the front side (the left side ofFIG. 1 ) and is formed by die-casting an aluminum alloy. - A cylindrical
shaft support portion 24a extends from the center of an inner wall surface of thebottom portion 24 in thefirst housing element 21. Ashaft support member 32, which has aninsertion hole 32a formed through the center thereof, is fixedly connected to an opening end of thecylindrical portion 23 in thefirst housing element 21. Arotary shaft 33 is accommodated in thefirst housing element 21. The rear end (the right end) of therotary shaft 33 is rotatably supported by theshaft support portion 24a of thefirst housing element 21 through abearing 34. The front end (the left side) of therotary shaft 33 is inserted through theinsertion hole 32a of theshaft support member 32, and is rotatably supported by theshaft support member 32 through abearing 35 in theinsertion hole 32a. - A
motor chamber 12 is defined in thehousing 11 and is located on the rear side ofFIG. 1 relative to theshaft support member 32. In themotor chamber 12, astator 36 is provided on the inner circumferential surface of thecylindrical portion 23 of thefirst housing element 21. In themotor chamber 12, arotor 37 is secured to therotary shaft 33 so as to be located inside thestator 36. Thestator 36 and therotor 37 constitute theelectric motor 13. Theelectric motor 13 integrally rotates therotor 37 and therotary shaft 33 by electric power externally supplied to thestator 36. - A fixed
scroll member 41 is accommodated in thefirst housing element 21 and is located near the opening end of thecylindrical portion 23. The fixedscroll member 41 includes a disc-shapedbase plate 61, a cylindrical outercircumferential wall 62 and aspiral wall 63. The outercircumferential wall 62 extends from the outer periphery of thebase plate 61. Thespiral wall 63 extends from thebase plate 61 and is located inside the outercircumferential wall 62. In thefirst housing element 21, a disc-shaped center frame or a fixedwall 31 is arranged between thefixed scroll member 41 and theshaft support member 32. A throughhole 31 a is formed through the center of thecenter frame 31. Anannular contact portion 31 b is located at the opening end near themotor chamber 12 in the throughhole 31 a and protrudes inward. - The fixed
scroll member 41 is connected to the outer periphery of thecenter frame 31 by the distal end surface of the outercircumferential wall 62. Anannular shim 68 is interposed at a joint between thefixed scroll member 41 and thecenter frame 31. Thebase plate 61 of the fixedscroll member 41, the outercircumferential wall 62 of the fixedscroll member 41 and thecenter frame 31 surround to define ascroll chamber 15 in thehousing 11. - A
crankshaft 43 is provided at the end surface of therotary shaft 33 near thecenter frame 31. Thecrankshaft 43 is mostly arranged in the throughhole 31 a of thecenter frame 31. Abushing 44 is fixedly fitted around thecrankshaft 43. Amovable scroll member 45 is accommodated in thescroll chamber 15 and is rotatably supported on thebushing 44 through abearing 46 so as to face the fixedscroll member 41. - A
balancer 44a is provided at the end of thebushing 44 near theshaft support member 32. Thebalancer 44a relieves imbalance on therotary shaft 33 due to uneven arrangement of themovable scroll member 45 around an axis L of therotary shaft 33. Thebalancer 44a is accommodated in abalancer chamber 14 outside the throughhole 31 a. Thebalancer chamber 14 is defined between theshaft support member 32 and thecenter frame 31. Thebalancer chamber 14 communicates with themotor chamber 12 through a clearance of thebearing 35. Accordingly, thebalancer chamber 14 has the same atmospheric pressure as that of themotor chamber 12. - The
movable scroll member 45 includes a disc-shapedbase plate 65 and aspiral wall 66 that extends toward the fixedscroll member 41. Aboss 67 is provided near the center of a back surface of thebase plate 65 and protrudes therefrom. Theboss 67 is fitted around thebushing 44 through the bearing 46 in the throughhole 31 a of thecenter frame 31. Anannular tip seal 77 is provided at the distal end of theboss 67. In the throughhole 31 a, theboss 67 slidably contacts with thecontact portion 31 b of thecenter frame 31 by thetip seal 77. Accordingly, in the throughhole 31 a, thetip seal 77 blocks communication between an inner space of theboss 67 communicating with thebalancer chamber 14 and an outer space of theboss 67. - The fixed
scroll member 41 and themovable scroll member 45 engage with each other by therespective spiral walls scroll chamber 15, while the distal end of thespiral wall 63 and the distal end of thespiral wall 66 contact with thebase plate 65 of themovable scroll member 45 and thebase plate 61 of the fixedscroll member 41, respectively. Accordingly, thebase plate 61 and thespiral wall 63 of the fixedscroll member 41 and thebase plate 65 and thespiral wall 66 of themovable scroll member 45 definecompression chambers 47 in thescroll chamber 15. - A self-
rotation blocking mechanism 48 is provided between thebase plate 65 of themovable scroll member 45 and thecenter frame 31 facing thebase plate 65. The self-rotation blocking mechanism 48 includes a plurality ofcylindrical holes 48a and a plurality ofpins 48b (only one of them is shown inFIG. 1 ). Thecylindrical holes 48a are recessed in radially outer portions of theback surface 65a of thebase plate 65 in themovable scroll member 45. Thepins 48b are buried in anend surface 31 c of thecenter frame 31 and are loosely fitted therein. - In the
scroll chamber 15, asuction chamber 51 is defined between the outercircumferential wall 62 of the fixedscroll member 41 and the outermost circumferential portion of thespiral wall 66 of themovable scroll member 45. Asuction passage 39 is formed in radially outer portions of theshaft support member 32, theshim 68 and thecenter frame 31 for interconnecting thesuction chamber 51 and themotor chamber 12. - A
suction port 50 is formed in thecylindrical portion 23 of thefirst housing element 21 and is located to correspond with themotor chamber 12. Thesuction port 50 connects with an external conduit, which further connects with an evaporator (not shown) of an external refrigerant circuit. Thesuction port 50 communicates with themotor chamber 12. Accordingly, relatively low pressure refrigerant gas from the external refrigerant circuit is introduced into thesuction chamber 51 through thesuction port 50, themotor chamber 12 and thesuction passage 39. - In the
housing 11, adischarge chamber 52 is defined between thesecond housing element 22 and the fixedscroll member 41. Adischarge port 53 for communicating with thedischarge chamber 52 is formed in thesecond housing element 22. Thedischarge port 53 connects with an external conduit, which further connects with a gas cooler (not shown) of the external refrigerant circuit. Accordingly, relatively high pressure refrigerant gas in thedischarge chamber 52 is delivered to the external refrigerant circuit through thedischarge port 53. - A
discharge hole 41 a is formed through the center of thebase plate 61 of the fixedscroll member 41. Thecompression chamber 47 near the center communicates with thedischarge chamber 52 through thedischarge hole 41 a. In thedischarge chamber 52, adischarge valve 55 constituted of a reed valve is arranged on thebase plate 61 of the fixedscroll member 41 for opening and closing thedischarge hole 41 a. The opening degree of thedischarge valve 55 is regulated by aretainer 56, which is fixedly arranged on thebase plate 61 of the fixedscroll member 41. - As the
rotary shaft 33 is rotated by theelectric motor 13, themovable scroll member 45 orbits around the axis (the axis L of the rotary shaft 33) of the fixedscroll member 41 through thecrankshaft 43. At the moment, the self-rotation of themovable scroll member 45 is blocked by the self-rotation blocking mechanism 48, so that only the orbital movement of themovable scroll member 45 is permitted. Due to the orbital movement of themovable scroll member 45, thecompression chambers 47 reduce in volume as thecompression chambers 47 move from the radially outer side of thespiral walls respective scroll members spiral walls suction chamber 51 to thecompression chambers 47 is compressed. The compressed refrigerant gas is discharged to thedischarge chamber 52 through thedischarge hole 41 a by pushing away thedischarge valve 55. - The operation for adjusting back pressure of the
movable scroll member 45 will now be described. - As shown in
FIG. 1 , in thescroll chamber 15, aback pressure chamber 16 is located on the side of theback surface 65a of thebase plate 65 of themovable scroll member 45. Thebase plate 65 and theboss 67 of themovable scroll member 45 and thecenter frame 31 surround to define theback pressure chamber 16. Communication between theback pressure chamber 16 and thebalancer chamber 14 is blocked by thetip seal 77, which is interposed between theboss 67 of themovable scroll member 45 and thecontact portion 31 b of thecenter frame 31. - As shown in
FIGs. 2 and 3A , in theback surface 65a of thebase plate 65 of themovable scroll member 45, anannular groove 65b for accommodating a seal is recessed in radially outer portion relative to thecylindrical recesses 48a so as to surround thecylindrical recesses 48a. Anannular seal member 75 constituted of a tip seal is fitted in thegroove 65b. Theback surface 65a of themovable scroll member 45 slidably and elastically contacts with anend surface 31c of thecenter frame 31 by theseal member 75. Namely, theseal member 75 is interposed at a clearance CL between theback surface 65a of themovable scroll member 45 and theend surface 31c of thecenter frame 31. Communication between theback pressure chamber 16 and thesuction chamber 51 through the entire clearance CL is blocked by theseal member 75. - Incidentally, a maximum distance of the clearance CL between the
movable scroll member 45 and thecenter frame 31, that is, a thrust clearance between themovable scroll member 45 and thecenter frame 31, is adjusted in an appropriate distance in such a manner that ashim 68 having an appropriate thickness is selected from a plurality ofshims 68 having different thicknesses and is assembled to the clearance CL when the electric compressor is manufactured. - As shown in
FIGs. 1 and2 , an introducingpassage 76 is formed in thebase plate 65 of themovable scroll member 45 so as to extend through thebase plate 65 in thickness. Two introducingpassages 76 are provided. Theback pressure chamber 16 and a volume-reducing (compressing)compression chamber 47A, which is a relatively high pressure region, are interconnected through one introducingpassage 76. Theback pressure chamber 16 and a volume-reducingcompression chamber 47B, which is different from thecompression chamber 47A, are interconnected through the other introducingpassage 76. The introducingpassages 76 are symmetrically located in thebase plate 65 from each other with an angle of 180 degrees with respect to the axis of thecrankshaft 43, and respectively open to the correspondingcompression chambers - A fixed
throttle 76a is arranged in each of the introducingpassages 76. In themovable scroll member 45, theback surface 65a of thebase plate 65 forms twoaccommodating recesses 65c, with which the opening of each introducingpassage 76 on the side of theback pressure chamber 16 communicates. Acheck valve 78 constituted of a reed valve is accommodated in each of theaccommodating recesses 65c. Thecheck valves 78 each permit refrigerant gas supplied from thecompression chambers back pressure chamber 16, and block the refrigerant gas returned from theback pressure chamber 16 to thecompression chambers - As shown in
FIGs. 2 and 3A , aportion 75a for lowering sealing performance (hereinafter, aseal lowering portion 75a) relative to the other portion is provided for theseal member 75. Theseal lowering portion 75a is formed by splitting a portion of the annular seal member. Theback pressure chamber 16 and thesuction chamber 75, which is a relatively low pressure region, are interconnected through theseal lowering portion 75a of theseal member 75 in the clearance CL between themovable scroll member 45 and thecenter frame 31. Incidentally, inFIG. 2 , dimensions of theseal lowering portion 75a (a split portion in the seal member 75) are exaggeratedly illustrated for easier understanding. Actually, theseal lowering portion 75a is formed by an extremely narrow clearance. - Incidentally, according to the present invention, a relatively high pressure region means a region where relatively high pressure refrigerant gas, which is compressed by the fixed
scroll member 41 and themovable scroll member 45, exists, while a relatively low pressure region means a region where relatively low pressure refrigerant gas, which is yet to be compressed by the fixedscroll member 41 and themovable scroll member 45, exists. - As shown in
FIG. 1 , as pressure in the volume-reducingcompression chambers back pressure chamber 16 due to operation of the electric compressor, thecheck valve 78 opens so that the relatively high pressure refrigerant gas in the volume-reducingcompression chambers back pressure chamber 16 through the respective introducingpassages 76. Accordingly, the pressure in theback pressure chamber 16 rises so that force (back pressure force) F1 urging themovable scroll member 45 toward the fixedscroll member 41 is applied based upon the pressure in theback pressure chamber 16. On the other hand, force (thrust load) F2 based upon the pressure in thecompression chambers 47 is applied to themovable scroll member 45 toward a direction to leave the fixedscroll member 41. Accordingly, a position of themovable scroll member 45 relative to thecenter frame 31 is determined in accordance with a balance between the force F1 and the force F2. - As exaggeratedly shown in
FIG. 3A , for example, as the force F1 becomes greater than the force F2 (F1 > F2) due to an increase in the pressure in theback pressure chamber 16, themovable scroll member 45 is displaced in a direction in which theback surface 65a leaves theend surface 31 c of thecenter frame 31. Accordingly, sliding resistance between theback surface 65a of themovable scroll member 45 and theend surface 31 c of thecenter frame 31 is reduced. In addition, when the force F1 becomes greater than the force F2 (F1 > F2), themovable scroll member 45 is pressed against the fixedscroll member 41 so that sealing performance of thecompression chambers 47 improves. - As the
movable scroll member 45 leaves thecenter frame 31 to increase the clearance CL between themovable scroll member 45 and thecenter frame 31, the passing cross-sectional area of refrigerant gas increases at theseal lowering portion 75a of theseal member 75. Accordingly, the amount of refrigerant gas delivered from theback pressure chamber 16 to thesuction chamber 51 increases so that the pressure in theback pressure chamber 16 falls to reduce the force F1. - As exaggeratedly shown in
FIG. 3B , as the force F1 becomes smaller than the force F2 (F1 < F2) due to a reduction in the pressure in theback pressure chamber 16, themovable scroll member 45 is displaced in a direction in which theback surface 65a approaches theend surface 31 c of thecenter frame 31. Accordingly, sliding resistance between themovable scroll member 45 and the fixedscroll member 41 is reduced. - As the
movable scroll member 45 approaches thecenter frame 31 to reduce the clearance between themovable scroll member 45 and thecenter frame 31, the passing cross-sectional area of refrigerant gas reduces at theseal lowering portion 75a of theseal member 75. Accordingly, the amount of refrigerant gas delivered from theback pressure chamber 16 to thesuction chamber 51 reduces so that the pressure in theback pressure chamber 16 rises to increase the force F1. - Thus, the
movable scroll member 45 varies the clearance CL (distance) between theback surface 65a and theend surface 31 c of thecenter frame 31 in such a manner that the force F1 based upon the pressure in theback pressure chamber 16 becomes an appropriate magnitude in a correspondence with the force F2 based upon the pressure in thecompression chambers 47. The passing cross-sectional area of theseal lowering portion 75a is thereby autonomously adjusted. Incidentally, in the preferred embodiment, in order to enhance compression efficiency by improving sealing performance of thecompression chambers 47, the adjustment of the pressure in theback pressure chamber 16 is predetermined in such a manner that a state, where the force F1 applied to themovable scroll member 45 slightly exceeds the force F2, is maintained for a relatively long time. - According to the preferred embodiment, the following advantageous effects are obtained.
- (1) The
movable scroll member 45 varies the clearance CL between themovable scroll member 45 and thecenter frame 31 in such a manner that the force F1 based upon the pressure in theback pressure chamber 16 becomes an appropriate magnitude in a correspondence with the force F2 based upon the pressure in thecompression chambers 47. Thus, the passing cross-sectional area of theseal lowering portion 75a of theseal member 75 is autonomously adjusted. In comparison to a prior art in which an entire clearance CL between themovable scroll member 45 and thecenter frame 31 is utilized as a passage for delivering refrigerant gas from theback pressure chamber 16 to thesuction chamber 51, thesurfaces movable scroll member 45 and thecenter frame 31 need not be manufactured in high accuracy. Accordingly, the pressure in theback pressure chamber 16 is appropriately adjusted without an increase in cost for manufacturing the electric compressor. - (2) The
seal lowering portion 75a for lowering sealing performance of theseal member 75 is formed by splitting a portion of theannular seal member 75. Accordingly, theseal lowering portion 75a is easily formed in theseal member 75. - (3) The
shim 68 is interposed at a joint between thefixed scroll member 41 fixed to thehousing 11 and thecenter frame 31 also fixed to thehousing 11 for adjusting a thrust clearance between themovable scroll member 45 and thecenter frame 31. For example, in comparison to theshim 68 interposed at a sliding portion between themovable scroll member 45 and thecenter frame 31, the leakage of refrigerant gas at a portion where theshim 68 is interposed is prevented in the preferred embodiment. This leads to improving compression efficiency of the electric compressor. - (4) The
shaft support member 32, by which therotary shaft 33 is supported through thebearing 35, is independently provided from thecenter frame 31, on which themovable scroll member 45 slides. Thebalancer chamber 14 is defined between theshaft support member 32 and thecenter frame 31, and thebalancer 44a is accommodated in thebalancer chamber 14. For example, in comparison to a structure in which theshaft support member 32 is integrated with thecenter frame 31 as one component and thebalancer 44a is accommodated in the back pressure chamber 16 (This embodiment is not a departure from the present invention.), sealing of theback pressure chamber 16 becomes easy.
In other words, in a state of a comparative example, therotary shaft 33 is partially located in theback pressure chamber 16, so that theback pressure chamber 16 need be sealed by a lip seal. The lip seal, in view of its characteristic, tightly fastens therotary shaft 33 for performing desirable sealing performance. As a result, power loss of therotary shaft 33 increases, and appropriate seal of theback pressure chamber 16 and a reduction in power loss are not performed at the same time.
Incidentally, in the above comparative example, as disclosed in the Unexamined Japanese Patent Publication No.2000-249086 back surface 65a of themovable scroll member 45, and the back pressure chamber is formed by covering the pocket for applying back pressure with thecenter frame 31. Thus, therotary shaft 33 need not be sealed by the lip seal. However, in this state, since the suction pressure is partially applied to the back surface of themovable scroll member 45 other than the pressure in the back pressure chamber, it becomes complicated to appropriately set function for adjusting back pressure. Additionally, the pocket for applying back pressure need be recessed in themovable scroll member 45, so that cost for manufacturing increases.
The relatively high pressure region includes two volume-reducingcompression chambers passages 76 are provided. Onecompression chamber 47A and theback pressure chamber 16 are interconnected through one introducingpassage 76, while theother compression chamber 47B and theback pressure chamber 16 are interconnected through the other introducingpassage 76. Thus, relatively high pressure refrigerant gas is supplied from twocompression chambers back pressure chamber 16, so that the inclination of themovable scroll member 45 due to a reduction in pressure in thecompression chambers
Namely, for example, when onecompression chamber 47A only supplies relatively high pressure gas to the back pressure chamber 16 (this embodiment is not a departure from the present invention), pressure in thecompression chamber 47A is reduced by supplying the relatively high pressure refrigerant gas to theback pressure chamber 16, while pressure in theother compression chamber 47B, which is located on a side opposite to thecompression chamber 47A relative to the axis (the axis of the crankshaft 43) of themovable scroll member 45, is not reduced. Accordingly, force applied to themovable scroll member 45 based upon pressure in thecompression chambers movable scroll member 45 tends to incline relative to the axis of themovable scroll member 45. - (6) Carbon dioxide is employed as refrigerant for the refrigeration cycle. As described in the prior art, when carbon dioxide refrigerant is employed, passing cross-sectional area of a refrigerant gas passage between the
back pressure chamber 16 and thesuction chamber 51 need be much narrower at the maximum than that when fluorocarbon refrigerant is employed. Such a setting is easily handled by partially lowering sealing performance of theseal member 75 with low cost. - The present invention is not limited to the embodiment described above but may be modified into the following alternative embodiments.
- In alternative embodiments to the above preferred embodiment, the
balancer chamber 14 is defined as a relatively low pressure region, while thetip seal 77 for separating thebalancer chamber 14 from theback pressure chamber 16 is defined as a seal member. As shown inFIG. 4 , thetip seal 77 is partially split to form aseal lowering portion 77a for lowering sealing performance, and theback pressure chamber 16 and thebalancer chamber 14 are interconnected through theseal lowering portion 77a. - In this state, as the operation being described with reference to
FIGs. 1 and4 , for example, as the force F1 becomes greater than the force F2 (F1 > F2) due to a rise in the pressure in theback pressure chamber 16, themovable scroll member 45 is displaced in a direction in which the distal end surface of theboss 67 leaves thecontact portion 31 b of thecenter frame 31. Accordingly, a clearance between the distal end surface of theboss 67 and thecontact portion 31 b of thecenter frame 31 increases, so that the passing cross-sectional area for refrigerant gas increases at theseal lowering portion 77a of thetip seal 77. The amount of refrigerant gas delivered from theback pressure chamber 16 to thebalancer chamber 14 increases, and the pressure in theback pressure chamber 16 falls to reduce the force F1. - As the force F1 becomes smaller than the force F2 (F1 < F2) due to a reduction in the pressure in the
back pressure chamber 16, themovable scroll member 45 is displaced in a direction in which the distal end of theboss 67 approaches thecontact portion 31 b of thecenter frame 31. Accordingly, a clearance between the distal end surface of theboss 67 and thecontact portion 31 b of thecenter frame 31 reduces, so that the passing cross-sectional area for refrigerant gas reduces at theseal lowering portion 77a of thetip seal 77. The amount of refrigerant gas delivered from theback pressure chamber 16 to thebalancer chamber 14 reduces, and the pressure in theback pressure chamber 16 rises to increase the force F1. - According to another embodiment, the same advantageous effects, such as appropriate adjustment of pressure in the
back pressure chamber 16 with a relatively low-cost structure, are obtained. - As shown in
FIG. 5 , in addition to the structure described in the preferred embodiment, theback pressure chamber 16 and thebalancer chamber 14 are interconnected not through theseal lowering portion 75a but through anotherpassage 81. A differentialpressure regulating valve 82 is arranged in thepassage 81 for opening when differential pressure between theback pressure chamber 16 and thebalancer chamber 14 is equal to or greater than a predetermined value. Incidentally, the differentialpressure regulating valve 82 includes aspherical valve body 82a, acoil spring 82b and aspring seat 82c. The pressure in theback pressure chamber 16 and the pressure in thebalancer chamber 14 are respectively applied to the front side and the rear side of thevalve body 82a. Thecoil spring 82b urges thevalve body 82a in a direction to close the valve. - As described in the preferred embodiment, the passing cross-sectional area of the
seal lowering portion 75a is adjusted in response to a balance between the force F1 based upon the pressure in theback pressure chamber 16 and the force F2 based upon the pressure in thecompression chambers 47. Namely, in the embodiment ofFIG. 5 , the pressure in theback pressure chamber 16 is adjusted by utilizing two valves (theseal lowering portion 75a and the differential pressure regulating valve 82) each having different characteristic. Accordingly, a region where only one of thevalves valves back pressure chamber 16 is further appropriately adjusted. - In the preferred embodiment, one portion of the
annular seal member 75 is split to form theseal lowering portion 75a. In alternative embodiments, a plurality of portions of a seal member, such as two, three, four, five or six portions, is split to form portion for lowering sealing performance at plural portions of the seal member. - In the preferred embodiment, the
seal lowering portion 75a is formed by partially splitting theannular seal member 75. In alternative embodiments, the annular shape of the seal member is maintained, while a groove is partially formed in the seal member. Thus, a seal lowering portion for lowering sealing performance is formed. - In the preferred embodiment, two volume-reducing
compression chambers back pressure chamber 16 through the respective introducingpassages 76. In alternative embodiments, two introducingpassages 76, which respectively extend from twocompression chambers back pressure chamber 16. Thus, only one portion of the movable scroll member 45 (the base plate 65) is recessed to form theaccommodating recess 65c, and the only onecheck valve 78 is required. Accordingly, cost for manufacturing the electric compressor is reduced. - In the preferred embodiment, relatively high pressure refrigerant gas is introduced from the volume-reducing
compression chambers back pressure chamber 16. In alternative embodiments, thecompression chamber 47 near the center (thecompression chamber 47 completes compression) or thedischarge chamber 52 is defined as a relatively high pressure region, while the upstream portion of the introducingpassage 76 communicates with the relatively high pressure region, so that the high pressure refrigerant gas, which is higher in pressure than the refrigerant gas in the volume-reducingcompression chambers back pressure chamber 16. - In the preferred embodiment, a scroll compressor is embodied as the electric compressor. The scroll compressor is not limited to the electric compressor. In alternative embodiments, a scroll compressor driven by an engine of a vehicle, a hybrid type scroll compressor having an electric motor and an engine as drive sources, may be employed.
- Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein but may be modified within the scope of the appended claims.
Claims (9)
- A scroll compressor comprising
a housing (11) including a fixed wall (31) and defining a relatively high pressure region (47, 47A, 47B, 52) and a relatively low pressure region (14, 51),
a fixed scroll member (41) having a base plate (61) and a spiral wall (62) extending from the base plate (61), the fixed scroll member (41) being fixedly connected to the housing (11),
a movable scroll member (45) having a base plate (65) and a spiral wall (66) extending from the base plate (65), the movable scroll member (45) being engaged with the fixed scroll member (41),
a back pressure chamber (16) defined in the housing (11) on a back surface (65a) side of the base plate (65) of the movable scroll member (45) between the movable scroll member (45) and the fixed wall (31),
an introducing passage (76) interconnecting the back pressure chamber (16) and the relatively high pressure region (47, 47A, 47B, 52),
a compression chamber (47) defined between the fixed scroll member (41) and the movable scroll member (45), the compression chamber (47) progressively reducing in volume by orbiting the movable scroll member (45) relative to the fixed scroll member (41), thus compressing gas,
an annular seal member (75, 77) provided on one of the movable scroll member (45) and the fixed wall (31) for sealing the back pressure chamber (16) as being slidable on the other of the movable scroll member (45) and the fixed wall (31),
characterized in that
a seal lowering portion (75a; 77a) for lowering a sealing performance is formed in the seal member (75, 77) to interconnect the back pressure chamber (16) and the relatively low pressure region (14, 51), wherein the seal lowering portion (75a; 77a) is being formed by partially splitting the seal member (75, 77) or by a groove in the seal member (75, 77). - The scroll compressor according to claim 1, wherein the movable scroll member (45) is accommodated in a scroll chamber (15), which is defined by connecting the fixed scroll member (41) and the fixed wall (31) at a joint,
characterized in that a shim (68) is interposed at the joint between the fixed scroll member (41) and the fixed wall (31) for adjusting a thrust clearance (CL) between the movable scroll member (45) and the fixed wall (31). - The scroll compressor according to any one of claims 1 and 2, comprising a rotary shaft (33), a shaft support member (32) and a balancer (44a),
characterized in that
the rotary shaft (33) includes a crankshaft (43) for supporting the movable scroll member (45),
the shaft support member (32) is fixedly connected to the fixed wall (31) on a side opposite to the movable scroll member (45) in the housing (11) and rotatably supports the rotary shaft (33), wherein a balancer chamber (14) is being defined between the fixed wall (31) and the shaft support member (32), and
the balancer (44a) is provided for the crankshaft (43) and is accommodated in the balancer chamber (14). - The scroll compressor according to any one of claims 1 through 3, wherein the back pressure chamber (16) communicates with the relatively low pressure region (14) through a passage (81) in addition to the seal lowering portion (77a),
characterized in that
a differential pressure regulating valve (82) is arranged in the passage (81) for opening the passage (81) when a pressure differential between the back pressure chamber (16) and the relatively low pressure region (14) is equal to or higher than a predetermined value. - The scroll compressor according to any one of claims 1 through 4, wherein the relatively high pressure region (47, 47A, 47B, 52) includes two volume-reducing compression chambers (47A, 47B), which respectively communicate with the back pressure chamber (16) through the introducing passage (76).
- The scroll compressor according to claim 5, wherein two volume-reducing compression chambers (47A, 47B) respectively communicate with the back pressure chamber (16) through the respective independent introducing passages (76).
- The scroll compressor according to any one of claims 1 through 6, wherein the introducing passage (76) is formed in the base plate (65) of the movable scroll member (45).
- The scroll compressor according to any one of claims 1 through 7, wherein carbon dioxide is employed as refrigerant of the refrigeration cycle.
- The scroll compressor according to any one of claims 1 through 8, wherein the compressor is driven by an electric motor (13).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2002370997A JP4007189B2 (en) | 2002-12-20 | 2002-12-20 | Scroll compressor |
JP2002370997 | 2002-12-20 |
Publications (2)
Publication Number | Publication Date |
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EP1433956A1 EP1433956A1 (en) | 2004-06-30 |
EP1433956B1 true EP1433956B1 (en) | 2012-02-29 |
Family
ID=32463494
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP03029176A Expired - Lifetime EP1433956B1 (en) | 2002-12-20 | 2003-12-18 | Scroll compressor |
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US (1) | US20040136854A1 (en) |
EP (1) | EP1433956B1 (en) |
JP (1) | JP4007189B2 (en) |
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US10753352B2 (en) | 2017-02-07 | 2020-08-25 | Emerson Climate Technologies, Inc. | Compressor discharge valve assembly |
US10975868B2 (en) | 2017-07-07 | 2021-04-13 | Emerson Climate Technologies, Inc. | Compressor with floating seal |
US11022119B2 (en) | 2017-10-03 | 2021-06-01 | Emerson Climate Technologies, Inc. | Variable volume ratio compressor |
US10962008B2 (en) | 2017-12-15 | 2021-03-30 | Emerson Climate Technologies, Inc. | Variable volume ratio compressor |
US10995753B2 (en) | 2018-05-17 | 2021-05-04 | Emerson Climate Technologies, Inc. | Compressor having capacity modulation assembly |
JP2020193575A (en) * | 2019-05-27 | 2020-12-03 | ダイキン工業株式会社 | Scroll compressor and refrigerator with the same |
US11692548B2 (en) | 2020-05-01 | 2023-07-04 | Emerson Climate Technologies, Inc. | Compressor having floating seal assembly |
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US11655818B2 (en) | 2020-05-26 | 2023-05-23 | Emerson Climate Technologies, Inc. | Compressor with compliant seal |
US11767846B2 (en) | 2021-01-21 | 2023-09-26 | Copeland Lp | Compressor having seal assembly |
US11655813B2 (en) | 2021-07-29 | 2023-05-23 | Emerson Climate Technologies, Inc. | Compressor modulation system with multi-way valve |
US11846287B1 (en) | 2022-08-11 | 2023-12-19 | Copeland Lp | Scroll compressor with center hub |
US11965507B1 (en) | 2022-12-15 | 2024-04-23 | Copeland Lp | Compressor and valve assembly |
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JPS61118580A (en) * | 1984-11-15 | 1986-06-05 | Matsushita Electric Ind Co Ltd | Scroll compressor |
US5040956A (en) * | 1989-12-18 | 1991-08-20 | Carrier Corporation | Magnetically actuated seal for scroll compressor |
US5607288A (en) * | 1993-11-29 | 1997-03-04 | Copeland Corporation | Scroll machine with reverse rotation protection |
JPH08151983A (en) * | 1994-11-30 | 1996-06-11 | Matsushita Electric Ind Co Ltd | Scroll compressor |
JP3010174B2 (en) * | 1995-11-24 | 2000-02-14 | 株式会社安永 | Scroll type fluid machine |
US6086342A (en) * | 1997-08-21 | 2000-07-11 | Tecumseh Products Company | Intermediate pressure regulating valve for a scroll machine |
US6077057A (en) * | 1997-08-29 | 2000-06-20 | Scroll Technologies | Scroll compressor with back pressure seal protection during reverse rotation |
JP2000045965A (en) * | 1998-07-29 | 2000-02-15 | Denso Corp | Scroll compressor |
JP4398539B2 (en) * | 1999-06-01 | 2010-01-13 | サンデン株式会社 | Scroll compressor |
JP3731433B2 (en) * | 1999-11-22 | 2006-01-05 | ダイキン工業株式会社 | Scroll compressor |
US6695599B2 (en) * | 2001-06-29 | 2004-02-24 | Nippon Soken, Inc. | Scroll compressor |
-
2002
- 2002-12-20 JP JP2002370997A patent/JP4007189B2/en not_active Expired - Fee Related
-
2003
- 2003-12-18 EP EP03029176A patent/EP1433956B1/en not_active Expired - Lifetime
- 2003-12-19 US US10/742,357 patent/US20040136854A1/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
US20040136854A1 (en) | 2004-07-15 |
JP4007189B2 (en) | 2007-11-14 |
EP1433956A1 (en) | 2004-06-30 |
JP2004204680A (en) | 2004-07-22 |
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