US20020039541A1 - Scroll compressor for introducing high-pressure fluid to thrust-face sude so as to decrease thrust load imposed on revolving scroll - Google Patents
Scroll compressor for introducing high-pressure fluid to thrust-face sude so as to decrease thrust load imposed on revolving scroll Download PDFInfo
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- US20020039541A1 US20020039541A1 US09/985,294 US98529401A US2002039541A1 US 20020039541 A1 US20020039541 A1 US 20020039541A1 US 98529401 A US98529401 A US 98529401A US 2002039541 A1 US2002039541 A1 US 2002039541A1
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- pressure
- scroll
- end plate
- thrust
- face
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- 239000012530 fluid Substances 0.000 title claims abstract description 36
- 230000007423 decrease Effects 0.000 title abstract description 3
- 238000007906 compression Methods 0.000 claims abstract description 34
- 230000006835 compression Effects 0.000 claims abstract description 29
- 239000007789 gas Substances 0.000 claims description 63
- 239000003921 oil Substances 0.000 claims description 51
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 38
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 36
- 239000010687 lubricating oil Substances 0.000 claims description 16
- 239000001569 carbon dioxide Substances 0.000 claims description 2
- 230000000593 degrading effect Effects 0.000 abstract description 4
- 230000003247 decreasing effect Effects 0.000 description 17
- 239000012071 phase Substances 0.000 description 7
- 239000011888 foil Substances 0.000 description 4
- 238000012423 maintenance Methods 0.000 description 4
- 239000003507 refrigerant Substances 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000011555 saturated liquid Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
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- 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
- F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
- F04C29/0021—Systems for the equilibration of forces acting on the pump
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- 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
- F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
- F04C18/02—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
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- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S418/00—Rotary expansible chamber devices
- Y10S418/01—Non-working fluid separation
Definitions
- the present invention relates to a scroll compressor, in particular, one suitable for operation in a vapour-compression refrigerating cycle which uses a refrigerant, such as CO 2 , in a supercritical area thereof.
- a refrigerant such as CO 2
- CO 2 in the gas phase is compressed using a compressor (A ⁇ B), and this hot and compressed CO 2 in the gas phase is cooled using a gas cooler (B ⁇ C).
- This cooled gas is further decompressed using a decompressor (C ⁇ D), and CO 2 in the gas-liquid phase is then vaporized (D ⁇ A), so that latent heat with respect to the evaporation is taken from an external fluid such as air, thereby cooling the external fluid.
- the critical temperature of CO 2 is approximately 31° C., that is, lower than that of Freon, the conventional refrigerant. Therefore, when the temperature of the outside air is high in the summer season or the like, the temperature of CO 2 at the gas cooler side is higher than the critical temperature of CO 2 . Therefore, in this case, CO 2 is not condensed at the outlet side of the gas cooler (that is, line segment B-C in FIG. 3 does not intersect with the saturated liquid curve SL).
- the condition at the outlet side of the gas cooler (corresponding to point C in FIG. 3) depends on the discharge pressure of the compressor and the CO 2 temperature at the outlet side of the gas cooler, and this CO 2 temperature at the outlet side depends on the discharge ability of the gas cooler and the outside temperature (which cannot be controlled).
- the condition at the outlet side of the gas cooler i.e., point C
- the discharge pressure of the compressor i.e., the pressure at the outlet side of the gas cooler. That is, in order to keep sufficient cooling ability (i.e., enthalpy difference) when the temperature of the outside air is high in the summer season or the like, higher pressure at the outlet side of the gas cooler is necessary as shown in the cycle E ⁇ F ⁇ G ⁇ H ⁇ E in FIG. 3. In order to satisfy this condition, the operating pressure of the compressor must be higher in comparison with the conventional refrigerating cycle using Freon.
- the operating pressure of the compressor is 3 kg/cm 2 in case of using R134 (i.e., conventional Freon), but 40 kg/cm 2 in case of CO 2 .
- the operation stopping pressure of the compressor of this example is 15 kg/cm 2 in case of using R134, but 100 kg/cm 2 in case of CO 2.
- a general scroll compressor comprises a casing; a fixed scroll and a revolving scroll in the housing, each scroll comprising an end plate and a spiral protrusion built on an inner surface of the end plate, said inner surface facing the other end plate so as to engage the protrusions of each scroll and form a spiral compression chamber.
- the introduced working gas is compressed in the compression chamber and then discharged according to the revolution of the revolving scroll.
- Japanese Examined Patent Application, Second Publication, Hei 1-44911 discloses the provision of a back pressure chamber at the back face side of the revolving scroll and support of the back face of the revolving scroll by using a piston forced by a spring.
- the structure for supporting the revolving scroll using a thrust ball bearing has the following problems: (i) loud noise is generated, and (ii) it is necessary to use a thrust ball bearing having a large diameter so as to secure a sufficiently long life; thus, it is difficult to manufacture a smaller scroll compressor.
- the structure in which the revolving scroll is simply supported using a thrust board sufficient effect of decreasing thrust loss cannot be obtained.
- an objective of the present invention is to provide a scroll compressor for effectively decreasing the thrust load imposed on the revolving scroll and improving the mechanical efficiency without degrading the compression efficiency, thereby realizing a simpler and smaller scroll compressor whose maintenance can be easily performed. Therefore, the present invention provides a scroll compressor comprising:
- a fixed scroll provided in the housing and comprising an end plate and a spiral protrusion built on one face of the end plate;
- a revolving scroll provided in the casing and comprising an end plate and a spiral protrusion built on one face of the end plate, wherein the spiral protrusions of each scroll are engaged with each other so as to form a spiral compression chamber, wherein:
- a thrust member for thrust-supporting the end plate of the revolving scroll is provided at the back-face side of the end plate of the revolving scroll;
- a pressure pocket is formed in a face of one of the thrust member and the end plate of the revolving scroll, wherein said face faces the other of the thrust member and the end plate of the revolving scroll;
- a high-pressure introduction hole for introducing a high-pressure fluid into the pressure pocket is provided at one of the thrust member side and the revolving scroll side.
- the high-pressure oil or working gas can be supplied as the high-pressure fluid via an oil supply path and an oil introduction hole (i.e., the high-pressure introduction hole); thereby decreasing the thrust load of the revolving scroll. Therefore, it is possible to prevent noises, and the thrust load imposed on the revolving scroll can be decreased by using the high-pressure fluid for a long period of time, thereby decreasing the mechanical loss.
- the scroll compressor according to the present invention can have a simpler structure in comparison with conventional scroll compressors; thus, the maintenance can be easily performed and a smaller body can be realized.
- a fluid path is formed in the casing; the high-pressure introduction hole is formed in the thrust member, where one end opens and joins the pressure pocket and the other end opens and joins the fluid path in the casing; and a high-pressure fluid is supplied from the compression chamber via the fluid path and the high-pressure introduction hole to the pressure pocket.
- a high-pressure fluid supply means for supplying the high-pressure fluid to the fluid path, where the supply means comprises an oil separator for lubricating oil from the discharged high-pressure working gas, and a return piping for returning the lubricating oil separated by the oil separator to the fluid path.
- the high-pressure oil can be reused.
- the high-pressure introduction hole is formed in the end plate of the revolving scroll, where one end opens and joins the pressure pocket and the other end opens and joins the compression chamber; and the working gas in the compression chamber is supplied as a high-pressure fluid via the high-pressure introduction hole to the pressure pocket. Accordingly, the high-pressure fluid in the compression chamber can be supplied to the pressure pocket.
- the high-pressure introduction hole is formed in the end plate of the revolving scroll, where one end opens and joins the pressure pocket and the other end opens and joins the compression chamber; and a plurality of compression chambers are provided by engaging the fixed scroll and the revolving scroll, and working gases having different pressures in the compression chambers are supplied as a high-pressure fluid via the high-pressure introduction hole to the pressure pocket.
- a plurality of high-pressure introduction holes may be provided, or a single high-pressure introduction hole may be ramified to form branch holes. Accordingly, preferably combined working gases having different pressures can be introduced into the pressure pocket.
- the working gas is carbon dioxide.
- the present invention can be effectively applied to a scroll compressor which uses a refrigerating cycle using CO 2 as the working gas, and which has a high operating pressure.
- FIG. 1 is a cross-sectional view in the longitudinal direction of an embodiment of the scroll compressor according to the present invention.
- FIG. 2 is an enlarged view of the vicinity of the thrust board shown in FIG. 1.
- FIG. 3 is a cross-sectional view in the longitudinal direction of another embodiment of the scroll compressor according to the present invention.
- FIGS. 4A and 4B are side and cross-sectional views of another example of the thrust board.
- FIG. 5 is a cross-sectional view in the longitudinal direction of another embodiment of the scroll compressor according to the present invention.
- FIG. 6 is a diagram showing a vapour-compression refrigerating cycle.
- FIG. 7 is a Mollier chart for CO 2 .
- the CO 2 cycle (structure) including the scroll compressor according to the present invention will be explained with reference to FIG. 6.
- the CO 2 cycle S in FIG. 6 is applied, for example, to the air conditioner of a vehicle.
- Reference numeral 1 indicates a scroll compressor for compressing CO 2 in the gas phase.
- This scroll compressor 1 receives driving force from a driving power supply (not shown) such as an engine.
- Reference numeral 1 a indicates a gas cooler for heat-exchanging CO 2 compressed in the scroll compressor 1 and outside air (or the like), so as to cool CO 2 .
- Reference numeral 1 b indicates a pressure control valve for controlling the pressure at the outlet side of the gas cooler 1 a according to the CO 2 temperature at the outlet side of the gas cooler 1 a .
- Reference numeral 1 d indicates an evaporator (i.e., heat absorber) as an air cooling means in the cabin of the vehicle.
- CO 2 in the gas-liquid two-phase state is vaporized (or evaporated) in the evaporator 1 d
- CO 2 takes heat (corresponding to the latent heat of CO 2 ) from the air in the cabin so that the air in the cabin is cooled.
- Reference numeral 1 e indicates an accumulator for temporarily storing CO 2 in the gas phase.
- the scroll compressor 1 , gas cooler 1 a , pressure control valve 1 b , restrictor 1 c , evaporator 1 d , and accumulator 1 e are connected via piping 1 f so as to form a closed circuit.
- Housing (or casing) 1 A of scroll compressor 1 includes cup-like main body 2 , and front case (i.e., crank case) 4 fastened to the main body 2 via bolt 3 .
- Reference numeral 5 indicates a crank shaft which pierces the front case 4 and is supported via main bearing 6 and sub bearing 7 by the front case 4 in a freely-rotatable form.
- the rotation of the engine (not shown) of the vehicle is transmitted via a known electromagnetic clutch 32 to the crank shaft 5 .
- Reference numerals 32 a and 32 b respectively indicate the coil and pulley of the electromagnetic clutch 32 .
- the fixed scroll 8 comprises end plate 10 and spiral protrusion (i.e., lap) 11 disposed on a surface of the plate 11 , and the surface facing end plate 17 explained later.
- a ring-shaped back pressure block 13 is detachably attached to the back face of end plate 10 by using a plurality of bolts 12 as fastening means.
- O rings 14 a and 14 b are provided (or embedded) in the inner-peripheral and outer-peripheral faces of the back pressure block 13 .
- the high-pressure chamber 16 consists of a space surrounded by smaller-diameter face 13 a of the back pressure block 13 , a space surrounded by larger-diameter face 13 b of the back pressure block 13 , this space being formed continuously with the above space surrounded by face 13 a , and a space surrounded by concave portion 10 a formed in the back face of the end plate 10 of fixed scroll 8 , this space being formed continuously with the above space surrounded by face 13 b .
- discharge port 34 i.e., top clearance
- discharge valve 35 for opening/closing this discharge port 34 is provided in the concave portion 10 a.
- the revolving scroll 9 comprises end plate 17 and spiral protrusion (i.e., lap) 18 which is disposed on a surface of the plate 17 , the surface facing the end plate 10 .
- the shape of the spiral protrusion 18 is substantially the same as that of the spiral protrusion 11 of the fixed scroll 8 .
- a ring-shaped plate spring 20 a is provided between the fixed scroll 8 and the main body 2 of the casing. A plurality of predetermined positions of the plate spring 20 a are alternately fastened to the fixed scroll 8 and to the main body 2 via bolts 20 b . According to this structure, the fixed scroll 8 can move only in its axial direction by the (amount of) maximum flexure of plate spring 20 a in the axial direction (i.e., a floating structure).
- the above ring-shaped plate springs 20 a and bolts 20 a form fixed scroll supporting apparatus (or axial-direction compliance supporting apparatus) 20 .
- gap C is provided, so that the back pressure block 13 can move in the axial direction described above.
- the fixed scroll 8 and the revolving scroll 9 are engaged in a manner such that the axes of these scrolls are eccentrically separated from each other by the radius of revolution (that is, in an eccentric form), and the phases of these scrolls differ from each other by 180° (refer to FIG. 1).
- the head surface of spiral protrusion 11 is in close contact with the inner surface (facing the end plate 10 ) of end plate 17
- the head surface of spiral protrusion 18 is in close contact with the inner surface (facing the end plate 17 ) of end plate 10 .
- rotation-preventing ring i.e., Oldham coupling
- the side faces of the spiral protrusions 11 and 18 contact each other at some positions so that enclosed spaces 21 a and 21 b are formed essentially at positions of point symmetry with respect to the center of the spiral.
- rotation-preventing ring i.e., Oldham coupling
- 27 for permitting the revolving scroll 9 to revolve, but prohibiting the rotation of the scroll 9 is provided between the fixed scroll 8 and revolving scroll 9 .
- discharge port 34 i.e., top clearance
- discharge valve 35 for opening/closing the discharge port 34 is directly attached to the end plate 10 of fixed scroll 8 . Therefore, it is unnecessary to form discharge port 34 in the back pressure block 13 , thereby decreasing the length and volume of the discharge port 34 . Accordingly, lower recompressive force of the compressor is necessary, thereby improving the operational ability.
- back pressure block 13 and fixed scroll 8 have separate bodies, and the back pressure block 13 is detachably attached to the fixed scroll 8 using bolts 12 (i.e., fastening means).
- bolts 12 i.e., fastening means
- a boss 22 is provided on (or projects from) a central area of the outer surface of the end plate 17 .
- a freely-rotatable drive bush 23 is inserted in the boss 22 via revolving bearing (or drive bearing) 24 which also functions as a radial bearing.
- a freely-rotatable eccentric shaft 26 projecting from the inner-side end of the crank shaft 5 , is inserted in through hole 25 provided in the drive bush 23 .
- thrust board (i.e., thrust member, explained later) 19 for thrust-supporting the revolving scroll 9 is provided between the outer-circumferential edge of the outer surface of end plate 17 and the front case 4 .
- a known mechanical seal (i.e., shaft seal) 28 used for sealing a shaft is provided around the crank shaft 5 , and this mechanical seal 28 comprises seat ring 28 a fixed to the front case 4 , and slave ring 28 b which rotates together with crank shaft 5 .
- This slave ring 28 b is forced by forcing member 28 c towards seat ring 28 a and closely contacts the seat ring 28 a , so that the slave ring 28 b rotationally slides on the seat ring 28 a in accordance with the rotation of the crank shaft 5 .
- a ring-shaped thrust board 19 is provided at the back side of the revolving scroll 9 .
- the thrust board 19 is close to and faces the end plate 17 of the revolving scroll 9 , and is attached to an end face of the front casing 4 .
- a ring-shaped pressure pocket 41 is opened in thrust face 40 of thrust board 19 (i.e., the face 40 at the end plate 17 side of revolving scroll 19 ), and high-pressure introduction hole 43 for introducing high-pressure oil into the pressure pocket 41 is opened from back face 42 of the pressure pocket 41 .
- This high-pressure introduction hole 43 is an L-shaped path which passes through the thrust board 19 .
- An oil supply path (i.e., fluid path) 44 joining the high-pressure introduction hole 43 is formed in main body 2 of housing (i.e., casing) 1 A.
- an oil separator 50 is attached to piping 1 f connected to discharge outlet 38 of scroll compressor 1 .
- This oil separator 50 is provided for separating lubricating oil (i.e., high-pressure oil) as a high-pressure fluid from the discharged working gas, and the separated lubricating oil is supplied to the oil supply path 44 via return piping 51 . That is, according to the operation of the scroll compressor 1 , lubricating oil is supplied into the scroll compressor 1 by a supply means (not shown), and the oil component included in the high-pressure working gas which is discharged from the discharge outlet 38 is filtered out when the working gas passes through the oil separator 50 . The gathered lubricating oil is introduced as high-pressure oil via return piping 51 , oil supply path 44 , and high-pressure introduction hole 43 into pressure pocket 41 , so that the pocket is filled with the high-pressure oil.
- lubricating oil i.e., high-pressure oil
- the working gas (refer to arrow A), which has flowed into suction chamber 15 through a suction inlet (not shown), enters enclosed space 21 a from an opening at the ends of the spiral protrusions 11 and 18 and reaches center space 21 c of the compression chambers while the gas is compressed.
- the compressed gas then passes through discharge port 34 provided in the end plate 10 of the fixed scroll 8 , and opens discharge valve 35 , so that the gas is discharged into high-pressure chamber 16 .
- the gas is further discharged outside via discharge outlet 38 .
- the fluid introduced from the suction chamber 15 is compressed in the enclosed spaces 21 a and 21 b , and this compressed gas is discharged.
- the oil component of the high-pressure working gas discharged from the discharge outlet 38 is filtered out when the working gas passes through oil separator 50 .
- the gathered lubricating oil is supplied as high-pressure oil via return piping 51 to oil supply path 44 , and this supplied high-pressure oil passes through high-pressure introduction hole 43 into pressure pocket 41 , so that the pocket is filled with the high-pressure oil.
- the revolving scroll 9 is uniformly thrust-supported by the function of the high-pressure oil, so that the thrust load imposed on the revolving scroll 9 can be decreased.
- thrust load F s on the revolving scroll 9 is decreased to “F z -F oil ”.
- gap C1 between the thrust board 19 and end plate 17 of revolving scroll 9 is set to be, for example, a few ⁇ m to a few ten ⁇ m, where the oil leaked from pressure pocket 41 through gap C1 is used as the lubricating oil.
- high-pressure oil is supplied from an external supply via oil supply path 44 and introduction hole 43 to pressure pocket 41 . Therefore, it is possible to prevent noises, and the thrust load imposed on the revolving scroll 9 can be decreased by using the high-pressure oil for a long period of time without degrading the compression efficiency, thereby decreasing the mechanical loss.
- the present scroll compressor has a simpler structure in comparison with conventional scroll compressors; thus, maintenance can be easily performed and a smaller body can be realized.
- the structure of the present embodiment comprises oil separator 50 (functioning as the high-pressure fluid supply means) for separating the lubricating oil from the high-pressure working gas, and lubricating oil return piping 51 for returning the lubricating oil separated by the oil separator 50 ; therefore, the high-pressure oil can be reused.
- the fixed scroll 8 can move in its axial direction (i.e., a floating structure), and back pressure is provided to the fixed scroll by using back pressure block 13 .
- the second embodiment has a non-floating structure in which the fixed scroll 8 is rigidly fixed to casing main body 2 by using bolt 12 , and no back pressure block is provided.
- O ring 14 is provided and embedded in the outer-peripheral face of end plate 10 of the fixed scroll 10 , thereby dividing the inside space of casing 2 into low-pressure chamber 15 and high-pressure chamber 16 .
- gap C2 (refer to FIG. 2) between the thrust board 19 and the end plate 17 of the revolving scroll 9 is smaller than gap C1 (also refer to FIG. 2) in the first embodiment, more specifically, C2 is approximately a few ⁇ m to 20 ⁇ m, so that leakage of high-pressure oil from gap C2 is prevented as much as possible.
- the other structural arrangements are the same as those shown in FIGS. 1 and 2, and explanations thereof are omitted.
- the pressure pocket 41 of the thrust board 19 has a ring-shaped structure; thus, if the (surface) accuracy of thrust face 40 of the thrust board 19 is partially degraded, the high-pressure oil excessively leaks from the corresponding portion of the pressure pocket 41 , and in such a case, the high-pressure oil may not be kept in the pressure pocket 41 .
- the thrust board 60 consists of two portions divided in the thickness direction, such as thrust-face side member 61 a at the thrust face side, and anti-thrust-face side member 61 b at the side opposed to the thrust face.
- a plurality of (e.g., 8) separate pressure pockets are formed in a circumferential direction, and circular path 64 for connecting the pressure pockets with each other is formed at a conjunction area of the members 61 a and 61 b .
- a high-pressure introduction hole 65 which opens in the outer-peripheral surface of the thrust board 60 is also formed at the conjunction area of the members 61 a and 61 b , where the introduction hole 65 joins the path 64 .
- the thrust-face and anti-thrust-face side members 61 a and 61 b are combined, for example, by welding, so that the thrust board 60 is formed. According to the above structure, even if the accuracy of the thrust face 62 of the thrust board 60 is partially degraded, excessive leakage of the high-pressure oil may occur only through a corresponding pressure pocket 63 , while sufficient high-pressure oil can be kept in the other pressure pockets, so that excessive leakage does not easily occur.
- lubricating oil return piping 51 may be omitted, and instead, a high-pressure oil tank for storing high-pressure oil may be provided so as to supply the high-pressure oil through the piping to the oil supply path 44 .
- the lubricating oil separated from the working gas by the oil separator 50 is supplied as the high-pressure fluid to the pressure pocket 41 ; however, a portion of the working gas discharged from the discharge outlet 38 may be introduced via the oil supply path 44 and high-pressure introduction hole 43 to the pressure pocket 41 . Furthermore, a medium-pressure element may be introduced from the compression chambers to the pressure pocket 41 .
- a ring-shaped pressure pocket 41 ′ is formed on a side face of end plate 17 of the revolving scroll 9 , where the side face contacts the thrust board 19 .
- a high-pressure introduction hole 43 ′ for supplying the compressed gas to the pressure pocket 41 ′ is provided, which joins the pressure pocket 41 ′.
- the other opening end of the high-pressure introduction hole 43 ′ joins the enclosed space 21 a or 21 b at the spiral protrusion 18 side of the end plate 17 .
- the other structural arrangements are the same as those of the first embodiment as shown in FIG. 1, and explanations thereof are omitted.
- the scroll compressor of the third embodiment a portion of the compressed gas in the enclosed space 21 a or 21 b is supplied via the high-pressure introduction hole 43 ′ to the pressure pocket 41 ′, and the compressed gas functioning as the high-pressure fluid receives a portion of the thrust load. Therefore, as in the above (first and second) embodiments explained above, noises can be prevented, and the thrust load imposed on the revolving scroll 9 can be decreased by using the compressed gas for a long period of time, thereby decreasing the mechanical loss.
- the present scroll compressor has a simpler structure in comparison with conventional scroll compressors; thus, the maintenance can be easily performed and a smaller body can be realized.
- the lubricating oil carried with the compressed gas leaked from the pressure pocket 41 ′ lubricates the inside of the scroll compressor 1 .
- the opening area of the pressure pocket 41 ′ is increased as much as possible.
- the other end of the high-pressure introduction hole 43 ′ is open towards enclosed space 21 a or 21 b , that is, one enclosed space; however, the high-pressure introduction hole may be open towards a plurality of enclosed spaces 21 a and 21 b so that working gases having different pressures are introduced into the pressure pocket 41 ′.
- a plurality of high-pressure introduction holes may be provided, or a single high-pressure introduction hole may be ramified to form branch holes. Accordingly, preferably combined working gases having different pressures can be introduced into the pressure pocket 41 ′.
- pressure pockets 41 , 63 and 41 ′ may be formed at either side of the revolving scroll 9 and the thrust board 19 . That is, in the first and second embodiments, pressure pockets 41 and 63 are formed in the thrust board 19 ; however, the pockets may be provided in the revolving scroll 9 . On the other hand, in the third embodiment, the pressure pocket 41 ′ is formed in the revolving scroll 9 , but may be formed in the thrust board 19 .
- the scroll compressor is applied to the CO 2 cycle using CO 2 as the working gas; however, the application is not limited to this type, and the compressor according to the present invention can be applied to the vapour-compression refrigerating cycle using a conventional working gas such as Freon.
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Abstract
A scroll compressor having a simple structure is disclosed, which effectively decreases the thrust load imposed on the revolving scroll without degrading the compression efficiency. The scroll compressor comprises a casing; a fixed scroll provided in the housing and comprising an end plate and a spiral protrusion built on one face of the end plate; and a revolving scroll provided in the casing and comprising an end plate and a spiral protrusion built on one face of the end plate, wherein the spiral protrusions of each scroll are engaged with each other so as to form a spiral compression chamber. In the above structure, an introduced working gas is compressed in the compression chamber and then discharged according to the revolution of the revolving scroll; a thrust member for thrust-supporting the end plate of the revolving scroll is provided at the back-face side of the end plate of the revolving scroll; a pressure pocket is formed in a face of one of the thrust member and the end plate of the revolving scroll, wherein said face faces the other of the thrust member and the end plate of the revolving scroll; and a high-pressure introduction hole for introducing a high-pressure fluid into the pressure pocket is provided at one of the thrust member side and the revolving scroll side.
Description
- 2. Field of the Invention
- The present invention relates to a scroll compressor, in particular, one suitable for operation in a vapour-compression refrigerating cycle which uses a refrigerant, such as CO2, in a supercritical area thereof.
- 2. Description of the Related Art
- As for the vapour-compression refrigerating cycle, one of the recently proposed measures to avoid the use of Freon (fron, a refrigerant) in order to protect the environment is the use of a refrigerating cycle using CO2 as the working gas (i.e., the refrigerant gas). This cycle is called “CO2 cycle” below. An example thereof is disclosed in Japanese Examined Patent Application, Second Publication, No. Hei 7-18602. The operation of this CO2 cycle is similar to the operation of a conventional vapour-compression refrigerating cycle using Freon. That is, as shown by the cycle A→B→C→D→A in FIG. 5 (which shows a CO2 Mollier chart), CO2 in the gas phase is compressed using a compressor (A→B), and this hot and compressed CO2 in the gas phase is cooled using a gas cooler (B→C). This cooled gas is further decompressed using a decompressor (C→D), and CO2 in the gas-liquid phase is then vaporized (D→A), so that latent heat with respect to the evaporation is taken from an external fluid such as air, thereby cooling the external fluid.
- The critical temperature of CO2 is approximately 31° C., that is, lower than that of Freon, the conventional refrigerant. Therefore, when the temperature of the outside air is high in the summer season or the like, the temperature of CO2 at the gas cooler side is higher than the critical temperature of CO2. Therefore, in this case, CO2 is not condensed at the outlet side of the gas cooler (that is, line segment B-C in FIG. 3 does not intersect with the saturated liquid curve SL). In addition, the condition at the outlet side of the gas cooler (corresponding to point C in FIG. 3) depends on the discharge pressure of the compressor and the CO2 temperature at the outlet side of the gas cooler, and this CO2 temperature at the outlet side depends on the discharge ability of the gas cooler and the outside temperature (which cannot be controlled). Therefore, substantially, the CO2 temperature at the outlet side of the gas cooler cannot be controlled. Accordingly, the condition at the outlet side of the gas cooler (i.e., point C) can be controlled by controlling the discharge pressure of the compressor (i.e., the pressure at the outlet side of the gas cooler). That is, in order to keep sufficient cooling ability (i.e., enthalpy difference) when the temperature of the outside air is high in the summer season or the like, higher pressure at the outlet side of the gas cooler is necessary as shown in the cycle E→F→G→H→E in FIG. 3. In order to satisfy this condition, the operating pressure of the compressor must be higher in comparison with the conventional refrigerating cycle using Freon. In an example of an air conditioner used in a vehicle, the operating pressure of the compressor is 3 kg/cm2 in case of using R134 (i.e., conventional Freon), but 40 kg/cm2 in case of CO2. In addition, the operation stopping pressure of the compressor of this example is 15 kg/cm2 in case of using R134, but 100 kg/cm2 in case of CO2.
- Here, a general scroll compressor comprises a casing; a fixed scroll and a revolving scroll in the housing, each scroll comprising an end plate and a spiral protrusion built on an inner surface of the end plate, said inner surface facing the other end plate so as to engage the protrusions of each scroll and form a spiral compression chamber. In this structure, the introduced working gas is compressed in the compression chamber and then discharged according to the revolution of the revolving scroll. In such a scroll compressor using CO2 as the working gas and having high operating pressure, the back face of the revolving scroll is supported using a thrust ball bearing so as to put up with or stand up to large thrust imposed on the revolving scroll, so that leakage of the working gas from the compression chamber is prevented as much as possible. As an example, Japanese Unexamined Patent Application, First Publication, Hei 3-54387 discloses supporting the back face of the revolving scroll by using a thrust board and to form a concave portion in a contact face between the thrust board and the revolving scroll so as to seal the relevant part from oil or water. As another example, Japanese Examined Patent Application, Second Publication, Hei 1-44911 discloses the provision of a back pressure chamber at the back face side of the revolving scroll and support of the back face of the revolving scroll by using a piston forced by a spring.
- The structure for supporting the revolving scroll using a thrust ball bearing has the following problems: (i) loud noise is generated, and (ii) it is necessary to use a thrust ball bearing having a large diameter so as to secure a sufficiently long life; thus, it is difficult to manufacture a smaller scroll compressor. In addition, in the structure in which the revolving scroll is simply supported using a thrust board, sufficient effect of decreasing thrust loss cannot be obtained.
- In consideration of the above circumstances, the inventors of the present invention diligently continued to research, and discovered that the thrust load can be effectively decreased, preferable lubricating effects can be obtained, and a smaller scroll compressor can be realized without degrading the compression efficiency, based on a simple arrangement such that a high-pressure oil or working gas is introduced from an external supply towards a face (of the thrust board) which faces the revolving scroll. Accordingly, an objective of the present invention is to provide a scroll compressor for effectively decreasing the thrust load imposed on the revolving scroll and improving the mechanical efficiency without degrading the compression efficiency, thereby realizing a simpler and smaller scroll compressor whose maintenance can be easily performed. Therefore, the present invention provides a scroll compressor comprising:
- a casing;
- a fixed scroll provided in the housing and comprising an end plate and a spiral protrusion built on one face of the end plate; and
- a revolving scroll provided in the casing and comprising an end plate and a spiral protrusion built on one face of the end plate, wherein the spiral protrusions of each scroll are engaged with each other so as to form a spiral compression chamber, wherein:
- an introduced working gas is compressed in the compression chamber and then discharged according to the revolution of the revolving scroll;
- a thrust member for thrust-supporting the end plate of the revolving scroll is provided at the back-face side of the end plate of the revolving scroll;
- a pressure pocket is formed in a face of one of the thrust member and the end plate of the revolving scroll, wherein said face faces the other of the thrust member and the end plate of the revolving scroll; and
- a high-pressure introduction hole for introducing a high-pressure fluid into the pressure pocket is provided at one of the thrust member side and the revolving scroll side.
- According to the above structure, the high-pressure oil or working gas can be supplied as the high-pressure fluid via an oil supply path and an oil introduction hole (i.e., the high-pressure introduction hole); thereby decreasing the thrust load of the revolving scroll. Therefore, it is possible to prevent noises, and the thrust load imposed on the revolving scroll can be decreased by using the high-pressure fluid for a long period of time, thereby decreasing the mechanical loss. In addition, the scroll compressor according to the present invention can have a simpler structure in comparison with conventional scroll compressors; thus, the maintenance can be easily performed and a smaller body can be realized.
- In order to supply the high-pressure fluid to the pressure pocket, it is possible that a fluid path is formed in the casing; the high-pressure introduction hole is formed in the thrust member, where one end opens and joins the pressure pocket and the other end opens and joins the fluid path in the casing; and a high-pressure fluid is supplied from the compression chamber via the fluid path and the high-pressure introduction hole to the pressure pocket.
- In a specific example, a high-pressure fluid supply means is provided for supplying the high-pressure fluid to the fluid path, where the supply means comprises an oil separator for lubricating oil from the discharged high-pressure working gas, and a return piping for returning the lubricating oil separated by the oil separator to the fluid path. In this case, the high-pressure oil can be reused.
- In another specific example, the high-pressure introduction hole is formed in the end plate of the revolving scroll, where one end opens and joins the pressure pocket and the other end opens and joins the compression chamber; and the working gas in the compression chamber is supplied as a high-pressure fluid via the high-pressure introduction hole to the pressure pocket. Accordingly, the high-pressure fluid in the compression chamber can be supplied to the pressure pocket.
- In another specific example, the high-pressure introduction hole is formed in the end plate of the revolving scroll, where one end opens and joins the pressure pocket and the other end opens and joins the compression chamber; and a plurality of compression chambers are provided by engaging the fixed scroll and the revolving scroll, and working gases having different pressures in the compression chambers are supplied as a high-pressure fluid via the high-pressure introduction hole to the pressure pocket. In order to introduce working gases of different pressures to the pressure pocket, a plurality of high-pressure introduction holes may be provided, or a single high-pressure introduction hole may be ramified to form branch holes. Accordingly, preferably combined working gases having different pressures can be introduced into the pressure pocket.
- Preferably, the working gas is carbon dioxide. In this case, the present invention can be effectively applied to a scroll compressor which uses a refrigerating cycle using CO2 as the working gas, and which has a high operating pressure.
- FIG. 1 is a cross-sectional view in the longitudinal direction of an embodiment of the scroll compressor according to the present invention.
- FIG. 2 is an enlarged view of the vicinity of the thrust board shown in FIG. 1.
- FIG. 3 is a cross-sectional view in the longitudinal direction of another embodiment of the scroll compressor according to the present invention.
- FIGS. 4A and 4B are side and cross-sectional views of another example of the thrust board.
- FIG. 5 is a cross-sectional view in the longitudinal direction of another embodiment of the scroll compressor according to the present invention.
- FIG. 6 is a diagram showing a vapour-compression refrigerating cycle.
- FIG. 7 is a Mollier chart for CO2.
- Hereinafter, embodiments of the scroll compressor according to the present invention will be explained with reference to the drawings.
- First, the CO2 cycle (structure) including the scroll compressor according to the present invention will be explained with reference to FIG. 6. The CO2 cycle S in FIG. 6 is applied, for example, to the air conditioner of a vehicle.
Reference numeral 1 indicates a scroll compressor for compressing CO2 in the gas phase. Thisscroll compressor 1 receives driving force from a driving power supply (not shown) such as an engine.Reference numeral 1 a indicates a gas cooler for heat-exchanging CO2 compressed in thescroll compressor 1 and outside air (or the like), so as to cool CO2.Reference numeral 1 b indicates a pressure control valve for controlling the pressure at the outlet side of thegas cooler 1 a according to the CO2 temperature at the outlet side of thegas cooler 1 a. CO2 is decompressed by thepressure control valve 1 b and restrictor 1 c, and CO2 enters into the gas-liquid phase (i.e., in the two-phase state).Reference numeral 1 d indicates an evaporator (i.e., heat absorber) as an air cooling means in the cabin of the vehicle. When CO2 in the gas-liquid two-phase state is vaporized (or evaporated) in theevaporator 1 d, CO2 takes heat (corresponding to the latent heat of CO2) from the air in the cabin so that the air in the cabin is cooled.Reference numeral 1 e indicates an accumulator for temporarily storing CO2 in the gas phase. Thescroll compressor 1,gas cooler 1 a,pressure control valve 1 b, restrictor 1 c,evaporator 1 d, andaccumulator 1 e are connected via piping 1 f so as to form a closed circuit. - The first embodiment of the
scroll compressor 1 will be explained with reference to FIG. 1. - Housing (or casing)1A of
scroll compressor 1 includes cup-likemain body 2, and front case (i.e., crank case) 4 fastened to themain body 2 viabolt 3.Reference numeral 5 indicates a crank shaft which pierces thefront case 4 and is supported viamain bearing 6 andsub bearing 7 by thefront case 4 in a freely-rotatable form. The rotation of the engine (not shown) of the vehicle is transmitted via a known electromagnetic clutch 32 to the crankshaft 5.Reference numerals electromagnetic clutch 32. - In the
housing 1A, fixedscroll 8 and revolvingscroll 9 are provided. - The fixed
scroll 8 comprisesend plate 10 and spiral protrusion (i.e., lap) 11 disposed on a surface of theplate 11, and the surface facingend plate 17 explained later. A ring-shaped backpressure block 13 is detachably attached to the back face ofend plate 10 by using a plurality ofbolts 12 as fastening means. O rings 14 a and 14 b are provided (or embedded) in the inner-peripheral and outer-peripheral faces of theback pressure block 13. These O rings 14 a and 14 b closely contact the inner-peripheral face ofmain body 2 of the casing, and high-pressure chamber (discharge chamber, explained later) 16 is separated from low-pressure chamber 15 (suction chamber) in themain body 2 of the casing. The high-pressure chamber 16 consists of a space surrounded by smaller-diameter face 13 a of theback pressure block 13, a space surrounded by larger-diameter face 13 b of theback pressure block 13, this space being formed continuously with the above space surrounded byface 13 a, and a space surrounded byconcave portion 10 a formed in the back face of theend plate 10 of fixedscroll 8, this space being formed continuously with the above space surrounded byface 13 b. In theend plate 10 of fixedscroll 8, discharge port 34 (i.e., top clearance) is opened, and dischargevalve 35 for opening/closing thisdischarge port 34 is provided in theconcave portion 10 a. - The revolving
scroll 9 comprisesend plate 17 and spiral protrusion (i.e., lap) 18 which is disposed on a surface of theplate 17, the surface facing theend plate 10. The shape of thespiral protrusion 18 is substantially the same as that of thespiral protrusion 11 of the fixedscroll 8. - A ring-shaped
plate spring 20 a is provided between thefixed scroll 8 and themain body 2 of the casing. A plurality of predetermined positions of theplate spring 20 a are alternately fastened to the fixedscroll 8 and to themain body 2 viabolts 20 b. According to this structure, the fixedscroll 8 can move only in its axial direction by the (amount of) maximum flexure ofplate spring 20 a in the axial direction (i.e., a floating structure). The above ring-shaped plate springs 20 a andbolts 20 a form fixed scroll supporting apparatus (or axial-direction compliance supporting apparatus) 20. Between the portion protruding from the back face of theback pressure block 13 andhousing 1A, gap C is provided, so that theback pressure block 13 can move in the axial direction described above. The fixedscroll 8 and the revolvingscroll 9 are engaged in a manner such that the axes of these scrolls are eccentrically separated from each other by the radius of revolution (that is, in an eccentric form), and the phases of these scrolls differ from each other by 180° (refer to FIG. 1). In addition, the head surface ofspiral protrusion 11 is in close contact with the inner surface (facing the end plate 10) ofend plate 17, while the head surface ofspiral protrusion 18 is in close contact with the inner surface (facing the end plate 17) ofend plate 10. Furthermore, the side faces of thespiral protrusions enclosed spaces scroll 9 to revolve, but prohibiting the rotation of thescroll 9 is provided between thefixed scroll 8 and revolvingscroll 9. - As explained above, discharge port (i.e., top clearance)34 is formed only in the
end plate 10 of fixedscroll 8, and dischargevalve 35 for opening/closing thedischarge port 34 is directly attached to theend plate 10 of fixedscroll 8. Therefore, it is unnecessary to formdischarge port 34 in theback pressure block 13, thereby decreasing the length and volume of thedischarge port 34. Accordingly, lower recompressive force of the compressor is necessary, thereby improving the operational ability. - In addition, back
pressure block 13 and fixedscroll 8 have separate bodies, and theback pressure block 13 is detachably attached to the fixedscroll 8 using bolts 12 (i.e., fastening means). In this structure, it is possible to easily attachdischarge valve 35 to theend plate 10 of fixedscroll 8 before theback pressure block 13 is attached to the fixedscroll 8, and the place of attachment is less limited. - A
boss 22 is provided on (or projects from) a central area of the outer surface of theend plate 17. A freely-rotatable drive bush 23 is inserted in theboss 22 via revolving bearing (or drive bearing) 24 which also functions as a radial bearing. In addition, a freely-rotatableeccentric shaft 26, projecting from the inner-side end of thecrank shaft 5, is inserted in throughhole 25 provided in thedrive bush 23. Furthermore, thrust board (i.e., thrust member, explained later) 19 for thrust-supporting the revolvingscroll 9 is provided between the outer-circumferential edge of the outer surface ofend plate 17 and thefront case 4. - A known mechanical seal (i.e., shaft seal)28 used for sealing a shaft is provided around the
crank shaft 5, and thismechanical seal 28 comprisesseat ring 28 a fixed to thefront case 4, andslave ring 28 b which rotates together withcrank shaft 5. Thisslave ring 28 b is forced by forcingmember 28 c towardsseat ring 28 a and closely contacts theseat ring 28 a, so that theslave ring 28 b rotationally slides on theseat ring 28 a in accordance with the rotation of thecrank shaft 5. - The distinctive portion of the present embodiment will be explained below.
- As shown in FIGS. 1 and 2, a ring-shaped
thrust board 19 is provided at the back side of the revolvingscroll 9. Thethrust board 19 is close to and faces theend plate 17 of the revolvingscroll 9, and is attached to an end face of thefront casing 4. A ring-shapedpressure pocket 41 is opened in thrust face 40 of thrust board 19 (i.e., theface 40 at theend plate 17 side of revolving scroll 19), and high-pressure introduction hole 43 for introducing high-pressure oil into thepressure pocket 41 is opened fromback face 42 of thepressure pocket 41. This high-pressure introduction hole 43 is an L-shaped path which passes through thethrust board 19. An oil supply path (i.e., fluid path) 44 joining the high-pressure introduction hole 43 is formed inmain body 2 of housing (i.e., casing) 1A. - As shown in FIG. 1, an
oil separator 50 is attached to piping 1 f connected to dischargeoutlet 38 ofscroll compressor 1. Thisoil separator 50 is provided for separating lubricating oil (i.e., high-pressure oil) as a high-pressure fluid from the discharged working gas, and the separated lubricating oil is supplied to theoil supply path 44 via return piping 51. That is, according to the operation of thescroll compressor 1, lubricating oil is supplied into thescroll compressor 1 by a supply means (not shown), and the oil component included in the high-pressure working gas which is discharged from thedischarge outlet 38 is filtered out when the working gas passes through theoil separator 50. The gathered lubricating oil is introduced as high-pressure oil via return piping 51,oil supply path 44, and high-pressure introduction hole 43 intopressure pocket 41, so that the pocket is filled with the high-pressure oil. - The operation of the
scroll compressor 1 will be explained below. - When the rotation of the vehicle engine is transmitted to the crank
shaft 5 by energizing thecoil 32 a of the electromagnetic clutch 32, the revolvingscroll 9 is driven by the rotation of thecrank shaft 5, transmitted via the revolution driving mechanism consisting ofeccentric shaft 26, throughhole 25,drive bush 23, revolvingbearing 24, andboss 22. The revolvingscroll 9 revolves along a circular orbit having a radius of revolution, while rotation of thescroll 9 is prohibited by the rotation-preventingring 27. - In this way, line-contact portions in the side faces of
spiral protrusions - Accordingly, the working gas (refer to arrow A), which has flowed into
suction chamber 15 through a suction inlet (not shown), enters enclosedspace 21 a from an opening at the ends of thespiral protrusions center space 21 c of the compression chambers while the gas is compressed. The compressed gas then passes throughdischarge port 34 provided in theend plate 10 of the fixedscroll 8, and opensdischarge valve 35, so that the gas is discharged into high-pressure chamber 16. The gas is further discharged outside viadischarge outlet 38. In this way, according to the revolution of the revolvingscroll 9, the fluid introduced from thesuction chamber 15 is compressed in theenclosed spaces - When the energizing process for
coil 32 a of electromagnetic clutch 32 is released so as to stop transmission of the rotating force to crankshaft 5, the operation of thescroll compressor 1 is stopped. When thecoil 32 a of electromagnetic clutch 32 is energized again, thescroll compressor 1 is activated again. - The oil component of the high-pressure working gas discharged from the
discharge outlet 38 is filtered out when the working gas passes throughoil separator 50. The gathered lubricating oil is supplied as high-pressure oil via return piping 51 tooil supply path 44, and this supplied high-pressure oil passes through high-pressure introduction hole 43 intopressure pocket 41, so that the pocket is filled with the high-pressure oil. The revolvingscroll 9 is uniformly thrust-supported by the function of the high-pressure oil, so that the thrust load imposed on the revolvingscroll 9 can be decreased. -
- In addition, given back pressure Fz which
fixed scroll 8 receives from theback pressure block 13, thrust load Fs on the revolvingscroll 9 is decreased to “Fz-Foil”. - In FIG. 2, gap C1 between the
thrust board 19 andend plate 17 of revolvingscroll 9 is set to be, for example, a few μm to a few ten μm, where the oil leaked frompressure pocket 41 through gap C1 is used as the lubricating oil. - As explained above, in the present embodiment, high-pressure oil is supplied from an external supply via
oil supply path 44 andintroduction hole 43 to pressurepocket 41. Therefore, it is possible to prevent noises, and the thrust load imposed on the revolvingscroll 9 can be decreased by using the high-pressure oil for a long period of time without degrading the compression efficiency, thereby decreasing the mechanical loss. In addition, the present scroll compressor has a simpler structure in comparison with conventional scroll compressors; thus, maintenance can be easily performed and a smaller body can be realized. - Furthermore, the oil leaked from the
pressure pocket 41 lubricates the inside of thescroll compressor 1. In addition, the structure of the present embodiment comprises oil separator 50 (functioning as the high-pressure fluid supply means) for separating the lubricating oil from the high-pressure working gas, and lubricating oil return piping 51 for returning the lubricating oil separated by theoil separator 50; therefore, the high-pressure oil can be reused. - Below, the second embodiment of the scroll compressor according to the present invention will be explained.
- In the scroll compressor as shown in FIG. 1, the fixed
scroll 8 can move in its axial direction (i.e., a floating structure), and back pressure is provided to the fixed scroll by using backpressure block 13. However, as shown in FIG. 3, the second embodiment has a non-floating structure in which the fixedscroll 8 is rigidly fixed to casingmain body 2 by usingbolt 12, and no back pressure block is provided.O ring 14 is provided and embedded in the outer-peripheral face ofend plate 10 of the fixedscroll 10, thereby dividing the inside space ofcasing 2 into low-pressure chamber 15 and high-pressure chamber 16. - In the second embodiment, gap C2 (refer to FIG. 2) between the
thrust board 19 and theend plate 17 of the revolvingscroll 9 is smaller than gap C1 (also refer to FIG. 2) in the first embodiment, more specifically, C2 is approximately a few μm to 20 μm, so that leakage of high-pressure oil from gap C2 is prevented as much as possible. The other structural arrangements are the same as those shown in FIGS. 1 and 2, and explanations thereof are omitted. - With Fth for separating the fixed
scroll 8 and revolvingscroll 9, the pressure of the high-pressure oil and the area of the opening of thepressure pocket 41 are determined so as to satisfy the condition “Foil (decreased thrust)>Fth” and to cope with the relevant (or whole) thrust load. - In addition, if tip seals (not shown) are provided and buried at the head surface of each spiral protrusion (i.e., tip head) of the fixed and revolving scrolls, the increase of loss due to leakage from the chip head can be prevented. In this case, the above condition “Foil>Fth” is not always necessary, and it is possible to prevent the oil leakage and also to decrease the thrust load.
- Accordingly, effects similar to those obtained by the first embodiment can also be obtained in the second embodiment.
- The
pressure pocket 41 of thethrust board 19 has a ring-shaped structure; thus, if the (surface) accuracy of thrust face 40 of thethrust board 19 is partially degraded, the high-pressure oil excessively leaks from the corresponding portion of thepressure pocket 41, and in such a case, the high-pressure oil may not be kept in thepressure pocket 41. - In order to solve the above problem, the following structure is effective. As shown in FIGS. 4A and 4B, the
thrust board 60 consists of two portions divided in the thickness direction, such as thrust-face side member 61 a at the thrust face side, and anti-thrust-face side member 61 b at the side opposed to the thrust face. In the thrust face 62 of the thrust-face side member 61 a, a plurality of (e.g., 8) separate pressure pockets are formed in a circumferential direction, andcircular path 64 for connecting the pressure pockets with each other is formed at a conjunction area of themembers pressure introduction hole 65 which opens in the outer-peripheral surface of thethrust board 60 is also formed at the conjunction area of themembers introduction hole 65 joins thepath 64. The thrust-face and anti-thrust-face side members thrust board 60 is formed. According to the above structure, even if the accuracy of the thrust face 62 of thethrust board 60 is partially degraded, excessive leakage of the high-pressure oil may occur only through acorresponding pressure pocket 63, while sufficient high-pressure oil can be kept in the other pressure pockets, so that excessive leakage does not easily occur. - In the above first and second embodiments, lubricating oil return piping51 may be omitted, and instead, a high-pressure oil tank for storing high-pressure oil may be provided so as to supply the high-pressure oil through the piping to the
oil supply path 44. - In addition, in the above-explained structure, the lubricating oil separated from the working gas by the
oil separator 50 is supplied as the high-pressure fluid to thepressure pocket 41; however, a portion of the working gas discharged from thedischarge outlet 38 may be introduced via theoil supply path 44 and high-pressure introduction hole 43 to thepressure pocket 41. Furthermore, a medium-pressure element may be introduced from the compression chambers to thepressure pocket 41. - Also in these cases, noises can be prevented and thrust imposed on the revolving
scroll 9 can be decreased, thereby decreasing the mechanical loss. - Below, the third embodiment according to the present invention will be explained.
- In the scroll compressor as shown in FIG. 5, a ring-shaped
pressure pocket 41′ is formed on a side face ofend plate 17 of the revolvingscroll 9, where the side face contacts thethrust board 19. A high-pressure introduction hole 43′ for supplying the compressed gas to thepressure pocket 41′ is provided, which joins thepressure pocket 41′. The other opening end of the high-pressure introduction hole 43′ joins the enclosedspace spiral protrusion 18 side of theend plate 17. The other structural arrangements are the same as those of the first embodiment as shown in FIG. 1, and explanations thereof are omitted. - In the scroll compressor of the third embodiment, a portion of the compressed gas in the enclosed
space pressure introduction hole 43′ to thepressure pocket 41′, and the compressed gas functioning as the high-pressure fluid receives a portion of the thrust load. Therefore, as in the above (first and second) embodiments explained above, noises can be prevented, and the thrust load imposed on the revolvingscroll 9 can be decreased by using the compressed gas for a long period of time, thereby decreasing the mechanical loss. In addition, the present scroll compressor has a simpler structure in comparison with conventional scroll compressors; thus, the maintenance can be easily performed and a smaller body can be realized. - In addition, the lubricating oil carried with the compressed gas leaked from the
pressure pocket 41′ lubricates the inside of thescroll compressor 1. - In order to exert a larger load on the compressed gas, preferably, the opening area of the
pressure pocket 41′ is increased as much as possible. - In the third embodiment, the other end of the high-
pressure introduction hole 43′ is open towardsenclosed space enclosed spaces pressure pocket 41′. In order to realize such a structure, a plurality of high-pressure introduction holes may be provided, or a single high-pressure introduction hole may be ramified to form branch holes. Accordingly, preferably combined working gases having different pressures can be introduced into thepressure pocket 41′. - In the above embodiments, pressure pockets41, 63 and 41′ may be formed at either side of the revolving
scroll 9 and thethrust board 19. That is, in the first and second embodiments, pressure pockets 41 and 63 are formed in thethrust board 19; however, the pockets may be provided in the revolvingscroll 9. On the other hand, in the third embodiment, thepressure pocket 41′ is formed in the revolvingscroll 9, but may be formed in thethrust board 19. - In the above explained embodiments, the scroll compressor is applied to the CO2 cycle using CO2 as the working gas; however, the application is not limited to this type, and the compressor according to the present invention can be applied to the vapour-compression refrigerating cycle using a conventional working gas such as Freon.
Claims (6)
1. A scroll compressor comprising:
a casing;
a fixed scroll provided in the housing and comprising an end plate and a spiral protrusion built on one face of the end plate; and
a revolving scroll provided in the casing and comprising an end plate and a spiral protrusion built on one face of the end plate, wherein the spiral protrusions of each scroll are engaged with each other so as to form a spiral compression chamber, wherein:
an introduced working gas is compressed in the compression chamber and then discharged according to the revolution of the revolving scroll;
a thrust member for thrust-supporting the end plate of the revolving scroll is provided at the back-face side of the end plate of the revolving scroll;
a pressure pocket is formed in a face of one of the thrust member and the end plate of the revolving scroll, wherein said face faces the other of the thrust member and the end plate of the revolving scroll; and
a high-pressure introduction hole for introducing a high-pressure fluid into the pressure pocket is provided at one of the thrust member side and the revolving scroll side.
2. A scroll compressor as claimed in claim 1 , wherein:
a fluid path is formed in the casing;
the high-pressure introduction hole is formed in the thrust member, where one end opens and joins the pressure pocket and the other end opens and joins the fluid path in the casing; and
a high-pressure fluid is supplied from the compression chamber via the fluid path and the high-pressure introduction hole to the pressure pocket.
3. A scroll compressor as claimed in claim 2 , further comprising a high-pressure fluid supply means for supplying the high-pressure fluid to the fluid path, where the supply means comprises an oil separator for lubricating oil from the discharged high-pressure working gas, and a return piping for returning the lubricating oil separated by the oil separator to the fluid path.
4. A scroll compressor as claimed in claim 1 , wherein:
the high-pressure introduction hole is formed in the end plate of the revolving scroll, where one end opens and joins the pressure pocket and the other end opens and joins the compression chamber; and
the working gas in the compression chamber is supplied as a high-pressure fluid via the high-pressure introduction hole to the pressure pocket.
5. A scroll compressor as claimed in claim 1 , wherein:
the high-pressure introduction hole is formed in the end plate of the revolving scroll, where one end opens and joins the pressure pocket and the other end opens and joins the compression chamber; and
a plurality of compression chambers are provided by engaging the fixed scroll and the revolving scroll, and working gases having different pressures in the compression chambers are supplied as a high-pressure fluid via the high-pressure introduction hole to the pressure pocket.
6. A scroll compressor as claimed in any one of claims 1 to 5 , wherein the working gas is carbon dioxide.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US09/985,294 US6428295B1 (en) | 1999-06-08 | 2001-11-02 | Scroll compressor for introducing high-pressure fluid to thrust-face side so as to decrease thrust load imposed on revolving scroll |
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JP11-161691 | 1999-06-08 | ||
JP16169199 | 1999-06-08 | ||
JP2000-060915 | 2000-03-06 | ||
JP2000060915A JP2001055988A (en) | 1999-06-08 | 2000-03-06 | Scroll compressor |
US09/588,776 US6334764B1 (en) | 1999-06-08 | 2000-06-07 | Scroll compressor for introducing high-pressure fluid to thrust-face side so as to decrease thrust load imposed on revolving scroll |
US09/985,294 US6428295B1 (en) | 1999-06-08 | 2001-11-02 | Scroll compressor for introducing high-pressure fluid to thrust-face side so as to decrease thrust load imposed on revolving scroll |
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US09/588,776 Division US6334764B1 (en) | 1999-06-08 | 2000-06-07 | Scroll compressor for introducing high-pressure fluid to thrust-face side so as to decrease thrust load imposed on revolving scroll |
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US20020039541A1 true US20020039541A1 (en) | 2002-04-04 |
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US09/588,776 Expired - Lifetime US6334764B1 (en) | 1999-06-08 | 2000-06-07 | Scroll compressor for introducing high-pressure fluid to thrust-face side so as to decrease thrust load imposed on revolving scroll |
US09/985,294 Expired - Lifetime US6428295B1 (en) | 1999-06-08 | 2001-11-02 | Scroll compressor for introducing high-pressure fluid to thrust-face side so as to decrease thrust load imposed on revolving scroll |
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Application Number | Title | Priority Date | Filing Date |
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US09/588,776 Expired - Lifetime US6334764B1 (en) | 1999-06-08 | 2000-06-07 | Scroll compressor for introducing high-pressure fluid to thrust-face side so as to decrease thrust load imposed on revolving scroll |
Country Status (7)
Country | Link |
---|---|
US (2) | US6334764B1 (en) |
EP (1) | EP1059448B1 (en) |
JP (1) | JP2001055988A (en) |
KR (1) | KR100349480B1 (en) |
CN (1) | CN1131378C (en) |
DE (1) | DE60013357T2 (en) |
NO (1) | NO20002916L (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060130495A1 (en) * | 2004-07-13 | 2006-06-22 | Dieckmann John T | System and method of refrigeration |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2001055988A (en) | 1999-06-08 | 2001-02-27 | Mitsubishi Heavy Ind Ltd | Scroll compressor |
KR100439651B1 (en) * | 2000-11-06 | 2004-07-12 | 미츠비시 쥬고교 가부시키가이샤 | Scroll compressor |
JP2002339883A (en) * | 2001-05-16 | 2002-11-27 | Nippon Soken Inc | Scroll compressor |
US7104075B2 (en) * | 2004-07-19 | 2006-09-12 | Snap-On Incorporated | Arrangement and method for controlling the discharge of carbon dioxide for air conditioning systems |
JP4192158B2 (en) * | 2005-03-24 | 2008-12-03 | 日立アプライアンス株式会社 | Hermetic scroll compressor and refrigeration air conditioner |
JP2007270697A (en) * | 2006-03-31 | 2007-10-18 | Hitachi Ltd | Scroll fluid machine |
DE102008013784B4 (en) * | 2007-03-15 | 2017-03-23 | Denso Corporation | compressor |
JP5341819B2 (en) * | 2010-05-18 | 2013-11-13 | サンデン株式会社 | Scroll type fluid machinery |
DE102016217358A1 (en) | 2016-09-12 | 2018-03-15 | Volkswagen Aktiengesellschaft | Scroll compressor |
KR102573097B1 (en) | 2022-01-14 | 2023-08-31 | 엘지전자 주식회사 | Scroll compressor |
KR102630534B1 (en) | 2022-01-14 | 2024-01-29 | 엘지전자 주식회사 | Scroll compressor |
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US3744942A (en) * | 1971-07-16 | 1973-07-10 | Borg Warner | Rotary sliding vane compressor with hydrostatic bearings |
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US4892469A (en) * | 1981-04-03 | 1990-01-09 | Arthur D. Little, Inc. | Compact scroll-type fluid compressor with swing-link driving means |
JPS58172401A (en) * | 1982-04-02 | 1983-10-11 | Hitachi Ltd | Scroll fluid machine |
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JPS62191690A (en) * | 1986-02-17 | 1987-08-22 | Tokico Ltd | Horizontal type scroll compressor |
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JP3066105B2 (en) * | 1991-05-10 | 2000-07-17 | 三洋電機株式会社 | Double rotation type scroll compressor |
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JPH06264876A (en) * | 1993-03-15 | 1994-09-20 | Toshiba Corp | Scroll compressor |
JP3232769B2 (en) * | 1993-04-26 | 2001-11-26 | 松下電器産業株式会社 | Scroll compressor and gas-liquid separator |
JPH0718602A (en) | 1993-06-29 | 1995-01-20 | Sekisui Chem Co Ltd | Tie plug |
JP3054387B2 (en) | 1997-07-30 | 2000-06-19 | キユーピー株式会社 | Eggshell powder with reduced odor components, method for treating the same, and method for producing the same |
JPH11241691A (en) * | 1998-02-25 | 1999-09-07 | Denso Corp | Scroll type electric compressor for co2 |
JP2001055988A (en) | 1999-06-08 | 2001-02-27 | Mitsubishi Heavy Ind Ltd | Scroll compressor |
JP2000352389A (en) | 1999-06-08 | 2000-12-19 | Mitsubishi Heavy Ind Ltd | Scroll compressor |
JP4043144B2 (en) | 1999-06-08 | 2008-02-06 | 三菱重工業株式会社 | Scroll compressor |
-
2000
- 2000-03-06 JP JP2000060915A patent/JP2001055988A/en active Pending
- 2000-05-04 KR KR1020000023864A patent/KR100349480B1/en active IP Right Grant
- 2000-06-06 CN CN00118004A patent/CN1131378C/en not_active Expired - Lifetime
- 2000-06-07 NO NO20002916A patent/NO20002916L/en not_active Application Discontinuation
- 2000-06-07 US US09/588,776 patent/US6334764B1/en not_active Expired - Lifetime
- 2000-06-08 DE DE60013357T patent/DE60013357T2/en not_active Expired - Lifetime
- 2000-06-08 EP EP00111854A patent/EP1059448B1/en not_active Expired - Lifetime
-
2001
- 2001-11-02 US US09/985,294 patent/US6428295B1/en not_active Expired - Lifetime
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060130495A1 (en) * | 2004-07-13 | 2006-06-22 | Dieckmann John T | System and method of refrigeration |
US7861541B2 (en) * | 2004-07-13 | 2011-01-04 | Tiax Llc | System and method of refrigeration |
Also Published As
Publication number | Publication date |
---|---|
KR100349480B1 (en) | 2002-08-21 |
DE60013357D1 (en) | 2004-10-07 |
DE60013357T2 (en) | 2005-09-01 |
EP1059448A3 (en) | 2002-03-27 |
EP1059448B1 (en) | 2004-09-01 |
JP2001055988A (en) | 2001-02-27 |
US6428295B1 (en) | 2002-08-06 |
NO20002916L (en) | 2000-12-11 |
US6334764B1 (en) | 2002-01-01 |
CN1276481A (en) | 2000-12-13 |
EP1059448A2 (en) | 2000-12-13 |
NO20002916D0 (en) | 2000-06-07 |
KR20010007042A (en) | 2001-01-26 |
CN1131378C (en) | 2003-12-17 |
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