WO2022103163A1 - Device for compressing a gaseous fluid - Google Patents

Device for compressing a gaseous fluid Download PDF

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Publication number
WO2022103163A1
WO2022103163A1 PCT/KR2021/016387 KR2021016387W WO2022103163A1 WO 2022103163 A1 WO2022103163 A1 WO 2022103163A1 KR 2021016387 W KR2021016387 W KR 2021016387W WO 2022103163 A1 WO2022103163 A1 WO 2022103163A1
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WO
WIPO (PCT)
Prior art keywords
drive shaft
sealing element
shaft
back pressure
lateral surface
Prior art date
Application number
PCT/KR2021/016387
Other languages
French (fr)
Inventor
Thomas Klotten
Original Assignee
Hanon Systems
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Publication date
Application filed by Hanon Systems filed Critical Hanon Systems
Publication of WO2022103163A1 publication Critical patent/WO2022103163A1/en

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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
    • F04C18/0207—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 both members having co-operating elements in spiral form
    • F04C18/0215—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 both members having co-operating elements in spiral form where only one member is moving
    • 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
    • F04C27/008—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids for other than working fluid, i.e. the sealing arrangements are not between working chambers of the machine
    • F04C27/009—Shaft sealings specially adapted for 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
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/02—Lubrication; Lubricant separation
    • F04C29/028—Means for improving or restricting lubricant flow

Definitions

  • the invention relates to a device for compressing a gaseous fluid, in particular a scroll compressor for compressing a refrigerant.
  • the device has a housing with a wall and a compression mechanism with an immovable stator as well as a movable orbiter.
  • the orbiter which is driven via a drive shaft and the wall of the housing are formed to enclose a back pressure area at least in areas.
  • Compressors known from the prior art for mobile applications, in particular for air conditioning systems of motor vehicles, for conveying of refrigerant through a refrigerant circuit, also referred to as refrigerant compressors, are frequently formed as a piston compressor with variable piston displacement or as a scroll compressor independent of the refrigerant.
  • the compressors are driven either via a pulley or electrically.
  • Conventional scroll compressors have, in addition to a housing, an immovable, stationary stator with a disk-shaped base plate and a spiral-shaped wall extending from a side of the base plate, as well as a movable orbiter likewise with a disk-shaped base plate and a spiral-shaped wall extending from a front side of the base plate.
  • the stator and the orbiter operate jointly.
  • the base plates are arranged relative to one another in such a way that the spiral-shaped walls engage one another.
  • the orbiter is moved on a circular path by means of an eccentric drive having a drive shaft and an intermediate element.
  • the prior art scroll compressors also have a wall arranged within the housing, fixedly connected to the housing and formed as a delimitation of a back pressure area, and which is, consequently, also referred to as counter wall. Because of the back pressure prevailing within the back pressure area formed between the counter wall and the orbiter, in particular a rear side of the base plate of the orbiter, the orbiter is pressed against the orbiter which is, just like the counter wall, fixed to the housing, by a force acting in the axial direction. The compressive force acting in the axial direction is controlled or regulated by the back pressure prevailing within the back pressure area, also referred to as contact pressure.
  • the level of the contact pressure is, as an intermediate pressure or medium pressure, between the levels of high pressure and low pressure.
  • the areas pressurized with high pressure and back pressure as well as with back pressure and low pressure are interconnected in each case, for example, via flow channels formed in the housing or in the interior of the drive shaft with integrated expansion devices.
  • the expansion device arranged between the areas pressurized with the high pressure and the back pressure must function very precisely, since the accuracy thereof considerably affects the value of the intermediate pressure as a back pressure in the back pressure area.
  • the corresponding sealing elements in particular a shaft sealing element, must ensure maximum tightness in order to prevent an overflow of the refrigerant from the back pressure area into the low pressure area and to define an overflow of the refrigerant from the high pressure area into the back pressure area exclusively by means of the expansion device.
  • the shaft sealing element provided for sealing the back pressure area from the low pressure area as intake area of the compressor between the rotating drive shaft and the counter wall of the housing and formed to be leakage-free, is neither lubricated nor cooled during the operation of the scroll compressor, so that high rotation speeds of the drive shaft and high pressure differentials result in high friction and therefore in heavy wear of the shaft sealing element, in particular in the area of the drive shaft.
  • the costs incurred for an expansion device arranged between the areas pressurized with the high pressure and the back pressure, and formed, in particular, as a nozzle, and the required effort associated with the production as well as with the assembly of the scroll compressors known from the prior art are very high, because, for example, in most cases a special station for assembling the expansion device on the production line is necessary and measurements of a possible pressure loss must be carried out following the assembly, to verify correct assembly.
  • the device should have as few individual components as possible and should be constructively easy to implement, also to minimize the costs of assembly and maintenance.
  • the object is achieved by a device according to the invention for compressing a gaseous fluid, in particular a scroll compressor for compressing a refrigerant circulating within a refrigerant circuit.
  • the device has a housing with a wall and a compression mechanism with an immovable stator as well as a movable orbiter.
  • the orbiter is driven via a drive shaft.
  • the wall of the housing and the orbiter are formed to enclose a back pressure area at least in areas.
  • the wall is formed between the back pressure area and an intake area delimiting the back pressure area from the intake area.
  • the drive shaft is arranged to project through a hole formed within the wall delimiting the back pressure area from the intake area.
  • a shaft sealing element is provided for sealing the back pressure area from the intake area.
  • a sealing surface with a through-hole breaking the sealing surface as well as interconnecting the back pressure area and the intake area hydraulically is formed between the drive shaft and the shaft sealing element.
  • a support surface at which the drive shaft and the shaft sealing element abut each other is regarded as a sealing surface.
  • the drive shaft is formed in the shape of a circular cylinder, while the shaft sealing element preferably has the shape of a circular ring.
  • the shaft sealing element preferably abuts on a lateral surface of the drive shaft circumferentially.
  • the shaft sealing element has a first hollow circular cylinder-shaped component and a second hollow circular cylinder-shaped component, which are formed integrally as a coherent unit and enclose the drive shaft completely in each case.
  • the first component of the shaft sealing element forming the sealing surface as a sealing lip, is arranged abutting on the lateral surface of the drive shaft circumferentially, preferably over its entire circumference.
  • a gap is formed between an inner lateral surface of the second component of the shaft sealing element and the lateral surface of the drive shaft, particularly a gap of uniform width both in a circumferential direction and in an axial direction, and thus a circular ring gap.
  • the width refers to an extension in the radial direction.
  • the lateral surface of the drive shaft has at least one recess.
  • the preferably groove-shaped recess extending in the axial direction is formed as a through-hole.
  • an extension of the recess in the axial direction is greater than an extension of the shaft sealing element in the axial direction.
  • the shaft sealing element abutting on the lateral surface of the drive shaft is aligned with the recess in such a way that the recess of the lateral surface of the drive shaft on both sides projects beyond the shaft sealing element in the axial direction.
  • the recess of the lateral surface of the drive shaft on both sides projects beyond the shaft sealing element in the axial direction.
  • the cross section of the through-hole arranged in a plane spanned perpendicular to the axial direction is enclosed, on the one hand, by boundary edges of the recess at least in areas and, on the other hand, a portion of the inner lateral surface of the shaft sealing element.
  • the recesses are arranged evenly distributed over the circumference of the lateral surface of the drive shaft.
  • an inner lateral surface of the shaft sealing element abutting on the lateral surface of the drive shaft has at least one contour for forming at least one through-hole.
  • the at least one contour can be formed, on the one hand, in the form of a groove extending in an axial direction.
  • the cross section of the through-hole arranged in the plane running perpendicular to the axial direction is enclosed, on the one hand, by boundary edges of the contour provided within the shaft sealing element and, on the other hand, a portion of the lateral surface of the drive shaft.
  • the respective through-hole in the plane oriented perpendicular to the axial direction has, without taking into account the curved lateral surfaces of the drive shaft and the shaft sealing element, respectively, preferably a substantially rectangular cross section or a substantially semicircular cross section.
  • the at least one contour provided on the inner lateral surface of the shaft sealing element abutting on the lateral surface of the drive shaft can be formed in the shape of a through-hole, in particular with a circular cross section.
  • the contours are arranged evenly distributed over the circumference of the lateral surface of the shaft sealing element.
  • the device has a first expansion device for expanding the gaseous fluid pressurizing the back pressure area from a level of an intermediate pressure p Z to a level of a low pressure p N within the intake area, as well as a second expansion device for expanding the gaseous fluid from a level of the high pressure p H to the level of the intermediate pressure p Z within the back pressure area, as well as a regulating means or a control device.
  • the through-hole is preferably formed as a first expansion device, while the second expansion device is preferably formed as a regulating valve.
  • the device according to the invention for compressing a gaseous fluid in particular as a further development of a scroll compressor with preferably electric drive, with the shaft sealing element arranged between the drive shaft and the wall for sealing the back pressure area from the intake area with a defined leakage has various other advantages:
  • Fig. 1 shows a section of a compression mechanism of a device for compressing a gaseous fluid, in particular a scroll compressor, in a lateral sectional view
  • Fig. 2a shows a section of the compression mechanism of a scroll compressor from the prior art with integrated expansion devices in a lateral sectional view
  • Fig. 2b to 2d show alternative embodiments of expansion devices of the compression mechanism of a scroll compressor from the prior art each in a lateral sectional view
  • Fig. 2e shows a sliding element with expansion function arranged at a wall of a housing between the wall and a movable orbiter of the compression mechanism
  • Fig. 3a shows a first embodiment of a drive shaft-housing connection with an interposed shaft sealing element as well as a sealing surface with a through-hole, in particular a drive shaft with a recess, in a perspective detailed view,
  • Fig. 3b shows a second embodiment of a drive shaft-housing connection with an interposed shaft sealing element and a sealing surface with a through-hole, in particular a shaft sealing element with a recess, in a perspective detailed view,
  • Fig. 3c shows an alternative second embodiment of a drive shaft-housing connection in a detailed perspective view
  • Fig. 4a to 4d show each a drive shaft of a first embodiment of a drive shaft-housing connection according to Fig. 3a in comparison to a drive shaft of a scroll compressor from the prior art, as well as
  • Fig. 5a to 5e show each a shaft sealing element of a second embodiment of a drive shaft-housing connection according to Fig. 3b in comparison to a shaft sealing element of a scroll compressor from the prior art.
  • Fig. 1 illustrates a section of a compression mechanism of a device 1 for compressing a gaseous fluid, in particular a scroll compressor 1, in a lateral sectional view.
  • the scroll compressor 1 has a housing 2, an immovable, stationary stator 3 with a disk-shaped base plate 3a and a spiral-shaped wall 3b extending from one side of the base plate 3a, as well as a movable orbiter 4 with a disk-shaped base plate 4a, and a spiral-shaped wall 4b extending from a front side of the base plate 4a.
  • Stator 3 and orbiter 4 which in brief are also called an immovable or fixed spiral 3 and a movable spiral 4, respectively, operate jointly.
  • the base plates 3a, 4a are arranged relative to one another in such a way that the wall 3b of the stator 3 and the wall 4b of the orbiter 4 engage one another.
  • the moveable spiral 4 is moved by means of an eccentric drive on a circular path.
  • the walls 3b, 4b contact one another at several points and form several consecutive, closed working spaces 5 within the walls 3b, 4b, wherein adjacent working spaces 5 delimit volumes of various sizes.
  • the volumes and the positions of the working spaces 5 are changed.
  • the volumes of the working spaces 5 become increasingly smaller towards the middle or towards the center of the spiral-shaped walls 3b, 4b, which are also referred to as spiral walls.
  • the gaseous fluid to be compressed and pressurizing the working spaces in particular a refrigerant, is compressed and ejected from the scroll compressor via an outlet.
  • the eccentric drive is formed from a drive shaft 6, which rotates about an axis of rotation 7, and an intermediate element 8.
  • the drive shaft 6 is supported via a first bearing 9, in particular a ball bearing, on the housing 2.
  • the orbiter 4 is eccentrically connected to the drive shaft 6 via the intermediate element 8, wherein the axes of the orbiter 4 and the drive shaft 6 are offset from one another.
  • the orbiter 4 is supported on the intermediate element 8 via a second bearing 10.
  • the scroll compressor 1 has also a guide device 11, which prevents a rotation of the movable spiral 4 and enables circling of the moveable spiral 4.
  • the guide device 11 comprises a plurality of circular holes 11-1, which are arranged adjacent to one another at certain intervals.
  • the holes 11-1 which are preferably formed as blind holes, are formed in a rear side of the base plate 4a of the movable spiral 4.
  • the guide device 11 has pins 11-2, which are formed to project from a wall 12 of the housing 2 and, in each case, engage a hole 11-1 formed in the base plate 4a of the movable spiral 4. A first end of the pins 11-2 protrudes from the wall 12, while a second end is arranged in the wall 12 of the housing 2.
  • a wall 12 fixed to the housing 2, also referred to as counter wall 12 is arranged within the housing 2.
  • a back pressure area 13 is formed between the counter wall 12 and the movable spiral 4.
  • the wall 12 delimits the back pressure area 13 formed between the orbiter 4 and the housing 2 and also forms a partition between the back pressure area 13 and an intake area 14.
  • the back pressure area 13 is formed on the rear side of the base plate 4a of the movable spiral 4 relative to the spiral-shaped walls 4b.
  • the moveable spiral 4 is pressed against the stationary spiral 3 which is fixed to the housing 2, by a force acting in the axial direction.
  • the compressive force acting in the axial direction as a result of the back pressure per area applied to the rear side of the disk-shaped base plate 4a of the moveable spiral 4 is controlled or regulated by the back pressure or contact pressure.
  • the level of the contact pressure is, as an intermediate pressure p Z or medium pressure, between the levels of the high pressure p H and the low pressure p N .
  • a shaft sealing element 15 is arranged, in particular in the area of the first bearing 9, between the drive shaft 6 and the counter wall 12.
  • a ring-shaped, in particular circular ring-shaped orbiter sealing element 16 is provided between the movable spiral 4 and the counter wall 12, which orbiter sealing element 16 abuts on a plate-shaped sliding element 12a arranged on a surface of the counter wall 12 that is oriented towards the movable spiral 4.
  • a lubricant in particular an oil, is added to the fluid.
  • Fig. 2a shows a section of the compression mechanism of a scroll compressor from the prior art with integrated expansion devices 17, 18 in a lateral sectional view
  • Fig. 2b to 2d illustrate alternative embodiments of expansion devices 17, 18 of different back pressure systems of scroll compressors from the prior art each in an lateral sectional view.
  • the back pressure systems of the conventional scroll compressors have a first expansion device 17 for expanding the refrigerant from the level of the back pressure or the intermediate pressure p Z to the level of the low pressure p N as well as a second expansion device 18 for expanding the refrigerant from the level of the high pressure p H to the level of the intermediate pressure p Z in a combination with a control means or a regulating means.
  • the back pressure system according to Fig. 2a has, for example, a first expansion device 17 formed as a nozzle and arranged in a flow channel 19, while a regulating valve serves as the second expansion device 18.
  • a filter element 20 is provided at the inlet to the flow channel 19 in order to prevent any particles that may be present, which are detached, for example, from the shaft sealing element 15 that is wearing on the drive shaft 6, from clogging the flow channel 19, in particular the inlet of the flow channel 19.
  • both the first expansion device 17 as well as the second expansion device 18 are arranged within a flow channel 19 interconnecting the low-pressure area and the high-pressure area.
  • An intermediate space formed between the expansion devices 17, 18 is hydraulically connected to the back pressure area 13 via a connection channel 21.
  • Figs. 2c and 2d each show a back pressure system with a flow channel 22 formed within the drive shaft 6a, which extends coaxially to the axis of rotation 7 of the drive shaft 6a between the end of the drive shaft 6a oriented towards the movable spiral 4 and thus the back pressure area 13 and the intake area.
  • the first expansion device 17 which is formed in particular as a nozzle, is arranged within the flow channel 22 interconnecting the back pressure area 13 and the low pressure area, while in the back pressure system according to Fig. 2d, the first expansion device 17 is formed in the area of the second bearing 10 as a through-bore oriented transversely to the axis of rotation 7 of the drive shaft 6a and thus in the radial direction, in combination with a recess of the drive shaft 6a.
  • the flow channel 22 is closed in the axial direction in the area of the second bearing 10.
  • the recess of the drive shaft 6a and an inner ring of the second bearing 10 delimit a flow channel which is connected to the intake area.
  • the through-bore represents a connection between the flow channel 22 formed within the drive shaft 6a and the flow channel delimited by the recess of the drive shaft 6a, which is formed in the shape of a groove or a notch and extends in the axial direction, and the inner ring of the second bearing 10.
  • Fig. 2e illustrates a sliding element 12a with an expansion function, which is arranged on the wall 12 of the housing 2 between the wall 12 and the movable orbiter 4 of the compression mechanism.
  • the plate-shaped sliding element 12a is formed with a channel extending in the circumferential direction as a first expansion device 17 for expanding the refrigerant from the level of the back pressure or the intermediate pressure p Z to the level of the low pressure p N .
  • the first expansion device 17 In a controlled back pressure system, the first expansion device 17 must be formed to function very precisely, since its accuracy is crucial for the value of the intermediate pressure p Z .
  • all sealing elements 15, 16 of the back pressure area 13, in particular the shaft sealing element 15, must be formed for ensuring a maximum tightness to avoid the leakage rate of the refrigerant from the back pressure area 13 into the intake area 14 or the low pressure area, and to define an overflow of the refrigerant from the high pressure area into the back pressure area 13 and thus the back pressure exclusively by means of the first expansion device 17.
  • the accuracy of the first expansion device 17 is less significant in a regulated back pressure system, since the value of the intermediate pressure p Z within the back pressure area 13 is defined by the second expansion device 18 formed, for example, as a regulating valve.
  • Figs. 3a to 3c illustrate a first embodiment and two alternative second embodiments of a drive shaft-housing connection each with an interposed shaft sealing element 15a, 15b, 15c as well as a sealing surface 23 with a through-hole 24a, 24b, 24c formed between the drive shaft 6a, 6b and the shaft sealing element 15a, 15b, 15c, in a perspective detailed view.
  • the through-hole 24a, 24b, 24c is formed as a first expansion device 17 for expanding the refrigerant from the level of the back pressure or the intermediate pressure p Z to the level of the low pressure p N in such a way that, in the area of the drive shaft-housing connection with the interposed shaft sealing element 15a, 15b, 15c, a defined leakage mass flow of the refrigerant flows from the back pressure area 13 into the intake area 14. Since the refrigerant is mixed with a lubricant, in particular an oil, a lubricant is applied to the sealing surface 23 which is, consequently, lubricated.
  • the circular ring-shaped shaft sealing element 15a, 15b, 15c has in each case a first hollow circular cylinder-shaped component 15-1a, 15-1b, 15-1c and a second hollow circular cylinder-shaped component 15-2 which are formed integrally as a coherent unit and enclose the circular cylindrical drive shaft 6a, 6b completely in each case.
  • An outer lateral surface of each of the components 15-1a, 15-1b, 15-1c, 15-2 abuts tightly and completely on an inner surface of a preferably circular hole of the wall 12.
  • a gap of uniform width is formed both in the circumferential direction and in the axial direction in each case, while the first component 15-1a, 15-1b, 15-1c of the shaft sealing element 15a, 15b, 15c formed as a sealing lip, circumferentially abuts on the surface of the drive shaft 6a, 6b for sealing the back pressure area 13 from the intake area 14.
  • the inner lateral surface of the first component 15-1a, 15-1b, 15-1c of the shaft sealing element 15a, 15b, 15c has a diameter which corresponds to the outer diameter of the surface of the drive shaft 6a, 6b.
  • the diameter of the inner lateral surface of the first component 15-1a, 15-1b, 15-1c is smaller than the outer diameter of the surface of the drive shaft 6a, 6b, in order to ensure the required tightness when elastically deformed in the assembled state.
  • the first embodiment of the drive shaft-housing connection has a shaft sealing element 15a interposed between the housing 2, especially of the wall 12, and the drive shaft 6b.
  • the first component 15-1a of the shaft sealing element 15a formed as sealing lip abuts completely on the outer surface of the drive shaft 6b substantially.
  • the surface of the drive shaft 6b has a recess 60 extending in the axial direction formed in the shape of a flat groove or a flat notch with a constant width and constant depth.
  • the width of the recess 60 is understood to mean the extension in the circumferential direction, while the depth extends in the radial direction of the drive shaft 6b.
  • the recess 60 has such an extension, also referred to as length, that the recess 60 projects beyond the shaft sealing element 15a on both sides, so that a through-hole 24a is formed in the area of the recess 60, which interconnects the back pressure area 13 and the intake area 14 hydraulically.
  • the length of the recess 60 is preferably greater than the width of recess 60, which in turn is greater than the depth of recess 60.
  • the through-hole 24a has, in the area of the first component 15-1a of the shaft sealing element 15a a substantially rectangular, free cross section, which is delimited, on a lower side, by a bottom of the recess 60 and on an upper side opposite the lower side by the shaft sealing element 15a. Since the recess 60, in the axial direction, projects, on the one hand, from the first component 15-1a of the shaft sealing element 15a and extends into the back pressure area 13, and on the other hand, projects from the second component 15-2 of the shaft sealing element 15a and extends into the intake area 14, the back pressure area 13 and the intake area 14 are interconnected via the through-hole 24a.
  • the through-hole 24a is widened by the gap formed between the inner lateral surface of the second component 15-2 of the shaft sealing element 15a and the surface of the drive shaft 6b.
  • the second embodiments of the drive shaft-housing connection are, according to Figs. 3b and 3c, each formed also with a shaft sealing element 15b, 15c interposed between the housing 2, in particular the wall 12, and a conventional drive shaft 6a.
  • the second component 15-2 of the shaft sealing element 15a of the first embodiment according to Fig. 3a and the second component 15-2 of the shaft sealing element 15b, 15c of the second embodiment are identical.
  • the first component 15-1b of the shaft sealing element 15b of the second embodiment according to Fig. 3b formed as sealing lip has, on the inner lateral surface oriented towards the surface of the drive shaft 6a, a contour 150b, in particular a recess formed in the shape of a flat groove or a flat notch with a substantially constant width, extending in the axial direction.
  • the width of the contour 150b is again understood to mean its extension in the circumferential direction. While the depth of the recess in the axial direction is constant, the depth of the recess may vary circumferentially, in particular, may steadily decrease towards an edge of the recess.
  • the contour 150b extends through the entire first component 15-1b of the shaft sealing element 15b, so that in the area of the shaft sealing element 15b, a through-hole 24b is formed, which hydraulically connects the back pressure area 13 with the intake area 14.
  • the width of the contour 150b is preferably greater than the depth of the contour 150b, which, as an extension in the radial direction, extends into the first component 15-1b of the shaft sealing element 15b.
  • the first component 15-1b of the shaft sealing element 15b formed as a sealing lip abuts, other than in the area of the contour 150b formed as a recess, completely on the outer surface of the drive shaft 6a.
  • the through-hole 24b has, in the area of the first component 15-1b of the shaft sealing element 15b a substantially rectangular or semicircular, free cross section, which is delimited, on a lower side, by the surface of the drive shaft 6a and on an upper side opposite the lower side or the side surfaces by the first component 15-1b of the shaft sealing element 15b.
  • the through-hole 24b corresponds to the gap formed between the inner lateral surface of the second component 15-2 of the shaft sealing element 15b and the surface of the drive shaft 6a.
  • the first component 15-1c of the shaft sealing element 15c of the alternative second embodiment according to Fig. 3c formed as a sealing lip has, on the inner lateral surface oriented to the surface of the drive shaft 6a, a contour 150c, in particular a recess formed in the shape of a through-hole with a circular cross section.
  • the contour 150c extends through the first component 15-1c of the shaft sealing element 15c, so that a through-hole 24c is formed in the area of the shaft sealing element 15c, that hydraulically connects the back pressure area 13 with the intake area 14.
  • the first component 15-1c of the shaft sealing element 15c, formed as a sealing lip abuts completely on the outer surface of the drive shaft 6a.
  • the through-hole 24c is completely delimited by the first component 15-1c of the shaft sealing element 15c.
  • the through-hole 24c again corresponds to the gap formed between the inner lateral surface of the second component 15-2 of the shaft sealing element 15c and the surface of the drive shaft 6a.
  • the outlet of the back pressure area 13 formed as a through-hole 24a, 24b, 24c is arranged at the level of the axis of rotation 7 of the drive shaft 6, 6a, 6b and thus preferably centrally within the back pressure area 13.
  • the level of lubricant in particular of the oil
  • lubrication of the bearings 9, 10 is improved.
  • the device 1 can be formed without a filter element 20, since the centrifugal force generated, when in operation, during the rotation of the drive shaft 6, 6a, 6b as well as the elements moved by the drive shaft 6, 6a, 6b, transports any unwanted particles possibly present outward in the radial direction and thus the through-hole 24a, 24b, 24c cannot clog. If, when the device 1 is at a standstill, as in the case of a pressure equalization during a compressor stop, particles accumulate in front of the through-hole 24a, 24b, 24c, the particles are removed in the aforementioned manner after start-up of the device 1 due to the rotation of the drive shaft 6, 6a, 6b.
  • Figs. 4a to 4d each illustrate a drive shaft 6b-1, 6b-2, 6b-3 of a first embodiment of a drive shaft-housing connection according to Fig. 3a, with at least one recess 60-1, 60-2 compared to a drive shaft 6a of a scroll compressor without a recess.
  • the groove-shaped recesses 60-1, 60-2 have substantially equal extensions in the axial direction.
  • the recesses 60-1, 60-2 of Figs. 4b and 4c provided in each case within the drive shafts 6b-1, 6b-2 differ both in the size and in the shape of the cross section formed in the plane oriented perpendicular to the axial direction. While the cross section of the recess 60-1 has a rectangular shape, the cross section of the recess 60-2 has a semicircular form. Here, the recess 60-1 is much wider than the recess 60-2.
  • the recesses 60-1, 60-2 can also have different depths, in particular in the range of 0.01 mm to 0.3 mm.
  • a plurality of recesses 60-2 are provided in the embodiment of the drive shaft 6b-3 according to Fig. 4d.
  • the recesses 60-2 are preferably arranged evenly distributed over the circumference of the surface of the drive shaft 6b-3 and can be in alignment in the axial direction.
  • the recesses are arranged with different lengths and optionally offset in the axial direction. Over the length of the recess 60, 60-1, 60-2 extending in the axial direction it is ensured in each case that in connection with the first component 15-1a and the second component 15-2 of the shaft sealing element 15a a corresponding expansion cross section is formed.
  • Figs. 5a to 5e each show a shaft sealing element 15b-1, 15b-2, 15b-3, 15b-4 of a second embodiment of a drive shaft-housing connection according to Fig. 3b with at least one contour 150b-1, 150b-2 compared to a shaft sealing element 15a of a scroll compressor without contour from the prior art.
  • the contours 150b-1, 150b-2 formed as a groove-shaped recess in each case have substantially the same extensions in the circumferential direction at least in the area of the inner diameter of the shaft sealing element 15b-1, 15b-2, 15b-3, 15b-4.
  • the contours 150b-1, 150b-2 of Figs. 5b and 5c provided within the shaft sealing element 15b-1, 15b-2 at the inner lateral surface differ both in the size and in the shape of the cross section formed in the plane oriented perpendicular to the axial direction. While the cross section of the contour 150b-1 has a rectangular shape, the cross section of the recess 150b-2 has a semicircular form. Here, the contour 150b-1 is much wider in the area of the outer radius due to the basic shape of the cross section than the contour 150b-2.
  • the contours 150b-1, 150b-2 can also have different depths, in particular in the range of 0.01 mm to 0.3 mm.
  • a plurality of contours 150b-2 are provided in the embodiments of the shaft sealing elements 15b-3, 15b-4, according to Figs. 5d and 5e.
  • the contours 150b-2 are each preferably arranged evenly distributed over the circumference of the inner lateral surface of the shaft sealing element 15b-3, 15b-4.
  • the cross section of the contours can have a rectangular shape or can have a semicircular form.

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Abstract

The invention relates to a device for compressing a gaseous fluid, in particular a scroll compressor for compressing a refrigerant. The device (1) has a housing (2) with a wall (12) and a compression mechanism with an immovable stator (3) as well as a movable orbiter (4).

Description

DEVICE FOR COMPRESSING A GASEOUS FLUID
The invention relates to a device for compressing a gaseous fluid, in particular a scroll compressor for compressing a refrigerant. The device has a housing with a wall and a compression mechanism with an immovable stator as well as a movable orbiter. The orbiter which is driven via a drive shaft and the wall of the housing are formed to enclose a back pressure area at least in areas.
Compressors known from the prior art for mobile applications, in particular for air conditioning systems of motor vehicles, for conveying of refrigerant through a refrigerant circuit, also referred to as refrigerant compressors, are frequently formed as a piston compressor with variable piston displacement or as a scroll compressor independent of the refrigerant. Here, the compressors are driven either via a pulley or electrically.
Conventional scroll compressors have, in addition to a housing, an immovable, stationary stator with a disk-shaped base plate and a spiral-shaped wall extending from a side of the base plate, as well as a movable orbiter likewise with a disk-shaped base plate and a spiral-shaped wall extending from a front side of the base plate. The stator and the orbiter operate jointly. Here, the base plates are arranged relative to one another in such a way that the spiral-shaped walls engage one another. The orbiter is moved on a circular path by means of an eccentric drive having a drive shaft and an intermediate element.
The prior art scroll compressors also have a wall arranged within the housing, fixedly connected to the housing and formed as a delimitation of a back pressure area, and which is, consequently, also referred to as counter wall. Because of the back pressure prevailing within the back pressure area formed between the counter wall and the orbiter, in particular a rear side of the base plate of the orbiter, the orbiter is pressed against the orbiter which is, just like the counter wall, fixed to the housing, by a force acting in the axial direction. The compressive force acting in the axial direction is controlled or regulated by the back pressure prevailing within the back pressure area, also referred to as contact pressure. Here, as a discharge pressure and intake pressure of the compressor, the level of the contact pressure is, as an intermediate pressure or medium pressure, between the levels of high pressure and low pressure.
The areas pressurized with high pressure and back pressure as well as with back pressure and low pressure are interconnected in each case, for example, via flow channels formed in the housing or in the interior of the drive shaft with integrated expansion devices.
In a controlled back pressure system, the expansion device arranged between the areas pressurized with the high pressure and the back pressure must function very precisely, since the accuracy thereof considerably affects the value of the intermediate pressure as a back pressure in the back pressure area. The corresponding sealing elements, in particular a shaft sealing element, must ensure maximum tightness in order to prevent an overflow of the refrigerant from the back pressure area into the low pressure area and to define an overflow of the refrigerant from the high pressure area into the back pressure area exclusively by means of the expansion device.
The shaft sealing element provided for sealing the back pressure area from the low pressure area as intake area of the compressor between the rotating drive shaft and the counter wall of the housing and formed to be leakage-free, is neither lubricated nor cooled during the operation of the scroll compressor, so that high rotation speeds of the drive shaft and high pressure differentials result in high friction and therefore in heavy wear of the shaft sealing element, in particular in the area of the drive shaft.
In addition, the costs incurred for an expansion device arranged between the areas pressurized with the high pressure and the back pressure, and formed, in particular, as a nozzle, and the required effort associated with the production as well as with the assembly of the scroll compressors known from the prior art are very high, because, for example, in most cases a special station for assembling the expansion device on the production line is necessary and measurements of a possible pressure loss must be carried out following the assembly, to verify correct assembly.
It is the object of the invention to provide a device for compressing a gaseous fluid, in particular the further development of a scroll compressor, to ensure an uninterrupted operation with maximum service life of the device. The device should have as few individual components as possible and should be constructively easy to implement, also to minimize the costs of assembly and maintenance.
The task is achieved by the subject matter with the features of the independent claim. Further developments are set forth in the dependent claims.
The object is achieved by a device according to the invention for compressing a gaseous fluid, in particular a scroll compressor for compressing a refrigerant circulating within a refrigerant circuit. The device has a housing with a wall and a compression mechanism with an immovable stator as well as a movable orbiter. The orbiter is driven via a drive shaft. The wall of the housing and the orbiter are formed to enclose a back pressure area at least in areas. Here, the wall is formed between the back pressure area and an intake area delimiting the back pressure area from the intake area.
The drive shaft is arranged to project through a hole formed within the wall delimiting the back pressure area from the intake area. In addition, in the area of the hole between the drive shaft and the wall, a shaft sealing element is provided for sealing the back pressure area from the intake area.
According to the conception of the invention, a sealing surface with a through-hole breaking the sealing surface as well as interconnecting the back pressure area and the intake area hydraulically is formed between the drive shaft and the shaft sealing element.
A support surface at which the drive shaft and the shaft sealing element abut each other is regarded as a sealing surface.
Advantageously, the drive shaft is formed in the shape of a circular cylinder, while the shaft sealing element preferably has the shape of a circular ring. Here, the shaft sealing element preferably abuts on a lateral surface of the drive shaft circumferentially.
According to a further development of the invention, the shaft sealing element has a first hollow circular cylinder-shaped component and a second hollow circular cylinder-shaped component, which are formed integrally as a coherent unit and enclose the drive shaft completely in each case. Here, in particular, the first component of the shaft sealing element, forming the sealing surface as a sealing lip, is arranged abutting on the lateral surface of the drive shaft circumferentially, preferably over its entire circumference.
Preferably, a gap is formed between an inner lateral surface of the second component of the shaft sealing element and the lateral surface of the drive shaft, particularly a gap of uniform width both in a circumferential direction and in an axial direction, and thus a circular ring gap. Here, the width refers to an extension in the radial direction. In a two-part embodiment of the shaft sealing element formed in such a way from a first hollow circular cylinder-shaped component and a second hollow circular cylinder-shaped component, the through-hole is expanded by the gap formed between the inner lateral surface of the second component and the lateral surface of the drive shaft in the area of the second component of the shaft sealing element.
According to a first alternative configuration of the invention, the lateral surface of the drive shaft has at least one recess. The preferably groove-shaped recess extending in the axial direction is formed as a through-hole. Here, an extension of the recess in the axial direction is greater than an extension of the shaft sealing element in the axial direction. In addition, the shaft sealing element abutting on the lateral surface of the drive shaft is aligned with the recess in such a way that the recess of the lateral surface of the drive shaft on both sides projects beyond the shaft sealing element in the axial direction. The recess of the lateral surface of the drive shaft on both sides projects beyond the shaft sealing element in the axial direction.
The cross section of the through-hole arranged in a plane spanned perpendicular to the axial direction is enclosed, on the one hand, by boundary edges of the recess at least in areas and, on the other hand, a portion of the inner lateral surface of the shaft sealing element.
In a preferred embodiment of the lateral surface of the drive shaft with at least two recesses, the recesses are arranged evenly distributed over the circumference of the lateral surface of the drive shaft.
According to a second alternative configuration of the invention an inner lateral surface of the shaft sealing element abutting on the lateral surface of the drive shaft has at least one contour for forming at least one through-hole.
The at least one contour can be formed, on the one hand, in the form of a groove extending in an axial direction. Here, the cross section of the through-hole arranged in the plane running perpendicular to the axial direction is enclosed, on the one hand, by boundary edges of the contour provided within the shaft sealing element and, on the other hand, a portion of the lateral surface of the drive shaft.
In both the configuration of the lateral surface of the drive shaft with the at least one, in particular groove-shaped recess and the configuration of the inner lateral surface of the shaft sealing element abutting on the lateral surface of the drive shaft with the at least one, likewise in particular groove-shaped contour, the respective through-hole in the plane oriented perpendicular to the axial direction has, without taking into account the curved lateral surfaces of the drive shaft and the shaft sealing element, respectively, preferably a substantially rectangular cross section or a substantially semicircular cross section.
On the other hand, the at least one contour provided on the inner lateral surface of the shaft sealing element abutting on the lateral surface of the drive shaft can be formed in the shape of a through-hole, in particular with a circular cross section.
In an advantageous embodiment of the inner lateral surface of the shaft sealing element having at least two contours, the contours are arranged evenly distributed over the circumference of the lateral surface of the shaft sealing element.
According to a further development of the invention, the device has a first expansion device for expanding the gaseous fluid pressurizing the back pressure area from a level of an intermediate pressure pZ to a level of a low pressure pN within the intake area, as well as a second expansion device for expanding the gaseous fluid from a level of the high pressure pH to the level of the intermediate pressure pZ within the back pressure area, as well as a regulating means or a control device. Here, the through-hole is preferably formed as a first expansion device, while the second expansion device is preferably formed as a regulating valve.
In summary, the device according to the invention for compressing a gaseous fluid, in particular as a further development of a scroll compressor with preferably electric drive, with the shaft sealing element arranged between the drive shaft and the wall for sealing the back pressure area from the intake area with a defined leakage has various other advantages:
- a small number of individual components and a simple assembly thereof result in only minimal assembly effort with minimal assembly costs,
- optimal lubrication of the shaft sealing element and the drive shaft cause only minimal friction and minimal wear, especially in the area of the sealing surfaces, as a result
- uninterrupted operation with maximum service life of the device with minimal operating costs.
Further details, features and advantages of configurations of the invention become apparent from the following description of exemplary embodiments with reference to the accompanying drawings.
Fig. 1: shows a section of a compression mechanism of a device for compressing a gaseous fluid, in particular a scroll compressor, in a lateral sectional view,
Fig. 2a: shows a section of the compression mechanism of a scroll compressor from the prior art with integrated expansion devices in a lateral sectional view,
Fig. 2b to 2d: show alternative embodiments of expansion devices of the compression mechanism of a scroll compressor from the prior art each in a lateral sectional view,
Fig. 2e: shows a sliding element with expansion function arranged at a wall of a housing between the wall and a movable orbiter of the compression mechanism,
Fig. 3a: shows a first embodiment of a drive shaft-housing connection with an interposed shaft sealing element as well as a sealing surface with a through-hole, in particular a drive shaft with a recess, in a perspective detailed view,
Fig. 3b: shows a second embodiment of a drive shaft-housing connection with an interposed shaft sealing element and a sealing surface with a through-hole, in particular a shaft sealing element with a recess, in a perspective detailed view,
Fig. 3c: shows an alternative second embodiment of a drive shaft-housing connection in a detailed perspective view,
Fig. 4a to 4d: show each a drive shaft of a first embodiment of a drive shaft-housing connection according to Fig. 3a in comparison to a drive shaft of a scroll compressor from the prior art, as well as
Fig. 5a to 5e: show each a shaft sealing element of a second embodiment of a drive shaft-housing connection according to Fig. 3b in comparison to a shaft sealing element of a scroll compressor from the prior art.
Fig. 1 illustrates a section of a compression mechanism of a device 1 for compressing a gaseous fluid, in particular a scroll compressor 1, in a lateral sectional view.
The scroll compressor 1 has a housing 2, an immovable, stationary stator 3 with a disk-shaped base plate 3a and a spiral-shaped wall 3b extending from one side of the base plate 3a, as well as a movable orbiter 4 with a disk-shaped base plate 4a, and a spiral-shaped wall 4b extending from a front side of the base plate 4a. Stator 3 and orbiter 4, which in brief are also called an immovable or fixed spiral 3 and a movable spiral 4, respectively, operate jointly. Here, the base plates 3a, 4a are arranged relative to one another in such a way that the wall 3b of the stator 3 and the wall 4b of the orbiter 4 engage one another.
The moveable spiral 4 is moved by means of an eccentric drive on a circular path. During the movement of the spiral 4, the walls 3b, 4b contact one another at several points and form several consecutive, closed working spaces 5 within the walls 3b, 4b, wherein adjacent working spaces 5 delimit volumes of various sizes. In response to the opposing movement of the two nested, spiral-shaped walls 3b, 4b, in particular to the movement of the orbiter 4, the volumes and the positions of the working spaces 5 are changed. The volumes of the working spaces 5 become increasingly smaller towards the middle or towards the center of the spiral-shaped walls 3b, 4b, which are also referred to as spiral walls. The gaseous fluid to be compressed and pressurizing the working spaces, in particular a refrigerant, is compressed and ejected from the scroll compressor via an outlet.
The eccentric drive is formed from a drive shaft 6, which rotates about an axis of rotation 7, and an intermediate element 8. The drive shaft 6 is supported via a first bearing 9, in particular a ball bearing, on the housing 2. The orbiter 4 is eccentrically connected to the drive shaft 6 via the intermediate element 8, wherein the axes of the orbiter 4 and the drive shaft 6 are offset from one another. The orbiter 4 is supported on the intermediate element 8 via a second bearing 10.
The scroll compressor 1 has also a guide device 11, which prevents a rotation of the movable spiral 4 and enables circling of the moveable spiral 4. In most cases, the guide device 11 comprises a plurality of circular holes 11-1, which are arranged adjacent to one another at certain intervals. Here, the holes 11-1 which are preferably formed as blind holes, are formed in a rear side of the base plate 4a of the movable spiral 4.
Furthermore, the guide device 11 has pins 11-2, which are formed to project from a wall 12 of the housing 2 and, in each case, engage a hole 11-1 formed in the base plate 4a of the movable spiral 4. A first end of the pins 11-2 protrudes from the wall 12, while a second end is arranged in the wall 12 of the housing 2.
A wall 12 fixed to the housing 2, also referred to as counter wall 12 is arranged within the housing 2. A back pressure area 13 is formed between the counter wall 12 and the movable spiral 4. The wall 12 delimits the back pressure area 13 formed between the orbiter 4 and the housing 2 and also forms a partition between the back pressure area 13 and an intake area 14. Here, the back pressure area 13 is formed on the rear side of the base plate 4a of the movable spiral 4 relative to the spiral-shaped walls 4b.
Because of the back pressure prevailing within the back pressure area 13, the moveable spiral 4 is pressed against the stationary spiral 3 which is fixed to the housing 2, by a force acting in the axial direction. The compressive force acting in the axial direction as a result of the back pressure per area applied to the rear side of the disk-shaped base plate 4a of the moveable spiral 4 is controlled or regulated by the back pressure or contact pressure. As a discharge pressure and intake pressure of the compressor, the level of the contact pressure is, as an intermediate pressure pZ or medium pressure, between the levels of the high pressure pH and the low pressure pN.
For sealing the back pressure area 13 and the intake area 14 against each other as two pressure chambers pressurized with different pressures, on the one hand, a shaft sealing element 15 is arranged, in particular in the area of the first bearing 9, between the drive shaft 6 and the counter wall 12. On the other hand, a ring-shaped, in particular circular ring-shaped orbiter sealing element 16 is provided between the movable spiral 4 and the counter wall 12, which orbiter sealing element 16 abuts on a plate-shaped sliding element 12a arranged on a surface of the counter wall 12 that is oriented towards the movable spiral 4.
To reduce frictional heat generated during the movement of the spiral-shaped walls 3b, 4b relative to one another and the spiral-shaped wall 4b of the orbiter 4 relative to the counter wall 12 and to improve the seals between the boundary surfaces of the working spaces 5 and between the back pressure area 13 and the intake area 14, a lubricant, in particular an oil, is added to the fluid.
Fig. 2a shows a section of the compression mechanism of a scroll compressor from the prior art with integrated expansion devices 17, 18 in a lateral sectional view, while Fig. 2b to 2d illustrate alternative embodiments of expansion devices 17, 18 of different back pressure systems of scroll compressors from the prior art each in an lateral sectional view.
The back pressure systems of the conventional scroll compressors have a first expansion device 17 for expanding the refrigerant from the level of the back pressure or the intermediate pressure pZ to the level of the low pressure pN as well as a second expansion device 18 for expanding the refrigerant from the level of the high pressure pH to the level of the intermediate pressure pZ in a combination with a control means or a regulating means.
The back pressure system according to Fig. 2a has, for example, a first expansion device 17 formed as a nozzle and arranged in a flow channel 19, while a regulating valve serves as the second expansion device 18. A filter element 20 is provided at the inlet to the flow channel 19 in order to prevent any particles that may be present, which are detached, for example, from the shaft sealing element 15 that is wearing on the drive shaft 6, from clogging the flow channel 19, in particular the inlet of the flow channel 19.
In the back pressure system according to Fig. 2b, both the first expansion device 17 as well as the second expansion device 18 are arranged within a flow channel 19 interconnecting the low-pressure area and the high-pressure area. An intermediate space formed between the expansion devices 17, 18 is hydraulically connected to the back pressure area 13 via a connection channel 21.
Figs. 2c and 2d each show a back pressure system with a flow channel 22 formed within the drive shaft 6a, which extends coaxially to the axis of rotation 7 of the drive shaft 6a between the end of the drive shaft 6a oriented towards the movable spiral 4 and thus the back pressure area 13 and the intake area.
In the backpressure system according to Fig. 2c, the first expansion device 17 which is formed in particular as a nozzle, is arranged within the flow channel 22 interconnecting the back pressure area 13 and the low pressure area, while in the back pressure system according to Fig. 2d, the first expansion device 17 is formed in the area of the second bearing 10 as a through-bore oriented transversely to the axis of rotation 7 of the drive shaft 6a and thus in the radial direction, in combination with a recess of the drive shaft 6a. The flow channel 22 is closed in the axial direction in the area of the second bearing 10. The recess of the drive shaft 6a and an inner ring of the second bearing 10 delimit a flow channel which is connected to the intake area. Here, the through-bore represents a connection between the flow channel 22 formed within the drive shaft 6a and the flow channel delimited by the recess of the drive shaft 6a, which is formed in the shape of a groove or a notch and extends in the axial direction, and the inner ring of the second bearing 10.
Fig. 2e illustrates a sliding element 12a with an expansion function, which is arranged on the wall 12 of the housing 2 between the wall 12 and the movable orbiter 4 of the compression mechanism. Here, the plate-shaped sliding element 12a is formed with a channel extending in the circumferential direction as a first expansion device 17 for expanding the refrigerant from the level of the back pressure or the intermediate pressure pZ to the level of the low pressure pN.
In a controlled back pressure system, the first expansion device 17 must be formed to function very precisely, since its accuracy is crucial for the value of the intermediate pressure pZ. In addition, all sealing elements 15, 16 of the back pressure area 13, in particular the shaft sealing element 15, must be formed for ensuring a maximum tightness to avoid the leakage rate of the refrigerant from the back pressure area 13 into the intake area 14 or the low pressure area, and to define an overflow of the refrigerant from the high pressure area into the back pressure area 13 and thus the back pressure exclusively by means of the first expansion device 17.
Compared to the controlled back pressure system, the accuracy of the first expansion device 17 is less significant in a regulated back pressure system, since the value of the intermediate pressure pZ within the back pressure area 13 is defined by the second expansion device 18 formed, for example, as a regulating valve.
Figs. 3a to 3c illustrate a first embodiment and two alternative second embodiments of a drive shaft-housing connection each with an interposed shaft sealing element 15a, 15b, 15c as well as a sealing surface 23 with a through- hole 24a, 24b, 24c formed between the drive shaft 6a, 6b and the shaft sealing element 15a, 15b, 15c, in a perspective detailed view.
The through- hole 24a, 24b, 24c is formed as a first expansion device 17 for expanding the refrigerant from the level of the back pressure or the intermediate pressure pZ to the level of the low pressure pN in such a way that, in the area of the drive shaft-housing connection with the interposed shaft sealing element 15a, 15b, 15c, a defined leakage mass flow of the refrigerant flows from the back pressure area 13 into the intake area 14. Since the refrigerant is mixed with a lubricant, in particular an oil, a lubricant is applied to the sealing surface 23 which is, consequently, lubricated.
The circular ring-shaped shaft sealing element 15a, 15b, 15c has in each case a first hollow circular cylinder-shaped component 15-1a, 15-1b, 15-1c and a second hollow circular cylinder-shaped component 15-2 which are formed integrally as a coherent unit and enclose the circular cylindrical drive shaft 6a, 6b completely in each case. An outer lateral surface of each of the components 15-1a, 15-1b, 15-1c, 15-2 abuts tightly and completely on an inner surface of a preferably circular hole of the wall 12.
Between the inner lateral surface of the second component 15-2 of the shaft sealing element 15a, 15b, 15c and the surface, in particular the lateral surface of the drive shaft 6a, 6b, a gap of uniform width is formed both in the circumferential direction and in the axial direction in each case, while the first component 15-1a, 15-1b, 15-1c of the shaft sealing element 15a, 15b, 15c formed as a sealing lip, circumferentially abuts on the surface of the drive shaft 6a, 6b for sealing the back pressure area 13 from the intake area 14. Here, in the assembled state of the device, the inner lateral surface of the first component 15-1a, 15-1b, 15-1c of the shaft sealing element 15a, 15b, 15c, on the one hand, has a diameter which corresponds to the outer diameter of the surface of the drive shaft 6a, 6b. On the other hand, in the unassembled state of the device, the diameter of the inner lateral surface of the first component 15-1a, 15-1b, 15-1c is smaller than the outer diameter of the surface of the drive shaft 6a, 6b, in order to ensure the required tightness when elastically deformed in the assembled state.
As shown in Fig. 3a, the first embodiment of the drive shaft-housing connection has a shaft sealing element 15a interposed between the housing 2, especially of the wall 12, and the drive shaft 6b. Here, the first component 15-1a of the shaft sealing element 15a formed as sealing lip abuts completely on the outer surface of the drive shaft 6b substantially.
The surface of the drive shaft 6b has a recess 60 extending in the axial direction formed in the shape of a flat groove or a flat notch with a constant width and constant depth. The width of the recess 60 is understood to mean the extension in the circumferential direction, while the depth extends in the radial direction of the drive shaft 6b.
In the axial direction, the recess 60 has such an extension, also referred to as length, that the recess 60 projects beyond the shaft sealing element 15a on both sides, so that a through-hole 24a is formed in the area of the recess 60, which interconnects the back pressure area 13 and the intake area 14 hydraulically. The length of the recess 60 is preferably greater than the width of recess 60, which in turn is greater than the depth of recess 60.
In a plane oriented perpendicular to the axial direction, the through-hole 24a has, in the area of the first component 15-1a of the shaft sealing element 15a a substantially rectangular, free cross section, which is delimited, on a lower side, by a bottom of the recess 60 and on an upper side opposite the lower side by the shaft sealing element 15a. Since the recess 60, in the axial direction, projects, on the one hand, from the first component 15-1a of the shaft sealing element 15a and extends into the back pressure area 13, and on the other hand, projects from the second component 15-2 of the shaft sealing element 15a and extends into the intake area 14, the back pressure area 13 and the intake area 14 are interconnected via the through-hole 24a.
In the area of the second component 15-2 of the shaft sealing element 15a, the through-hole 24a is widened by the gap formed between the inner lateral surface of the second component 15-2 of the shaft sealing element 15a and the surface of the drive shaft 6b.
The second embodiments of the drive shaft-housing connection are, according to Figs. 3b and 3c, each formed also with a shaft sealing element 15b, 15c interposed between the housing 2, in particular the wall 12, and a conventional drive shaft 6a. The second component 15-2 of the shaft sealing element 15a of the first embodiment according to Fig. 3a and the second component 15-2 of the shaft sealing element 15b, 15c of the second embodiment are identical.
The first component 15-1b of the shaft sealing element 15b of the second embodiment according to Fig. 3b formed as sealing lip has, on the inner lateral surface oriented towards the surface of the drive shaft 6a, a contour 150b, in particular a recess formed in the shape of a flat groove or a flat notch with a substantially constant width, extending in the axial direction. The width of the contour 150b is again understood to mean its extension in the circumferential direction. While the depth of the recess in the axial direction is constant, the depth of the recess may vary circumferentially, in particular, may steadily decrease towards an edge of the recess.
In the axial direction, the contour 150b extends through the entire first component 15-1b of the shaft sealing element 15b, so that in the area of the shaft sealing element 15b, a through-hole 24b is formed, which hydraulically connects the back pressure area 13 with the intake area 14. The width of the contour 150b is preferably greater than the depth of the contour 150b, which, as an extension in the radial direction, extends into the first component 15-1b of the shaft sealing element 15b. The first component 15-1b of the shaft sealing element 15b formed as a sealing lip abuts, other than in the area of the contour 150b formed as a recess, completely on the outer surface of the drive shaft 6a.
In a plane oriented perpendicular to the axial direction, the through-hole 24b has, in the area of the first component 15-1b of the shaft sealing element 15b a substantially rectangular or semicircular, free cross section, which is delimited, on a lower side, by the surface of the drive shaft 6a and on an upper side opposite the lower side or the side surfaces by the first component 15-1b of the shaft sealing element 15b.
In the area of the second component 15-2 of the shaft sealing element 15b, the through-hole 24b corresponds to the gap formed between the inner lateral surface of the second component 15-2 of the shaft sealing element 15b and the surface of the drive shaft 6a.
The first component 15-1c of the shaft sealing element 15c of the alternative second embodiment according to Fig. 3c formed as a sealing lip has, on the inner lateral surface oriented to the surface of the drive shaft 6a, a contour 150c, in particular a recess formed in the shape of a through-hole with a circular cross section. The contour 150c extends through the first component 15-1c of the shaft sealing element 15c, so that a through-hole 24c is formed in the area of the shaft sealing element 15c, that hydraulically connects the back pressure area 13 with the intake area 14. The first component 15-1c of the shaft sealing element 15c, formed as a sealing lip, abuts completely on the outer surface of the drive shaft 6a. The through-hole 24c is completely delimited by the first component 15-1c of the shaft sealing element 15c.
In the area of the second component 15-2 of the shaft sealing element 15c, the through-hole 24c again corresponds to the gap formed between the inner lateral surface of the second component 15-2 of the shaft sealing element 15c and the surface of the drive shaft 6a.
The outlet of the back pressure area 13 formed as a through- hole 24a, 24b, 24c is arranged at the level of the axis of rotation 7 of the drive shaft 6, 6a, 6b and thus preferably centrally within the back pressure area 13. As the level of lubricant, in particular of the oil, reaches the level of the through- hole 24a, 24b, 24c at least during standstill of the device 1 and the orbiter 4, respectively, or when operating at minimum speeds, it is ensured that the oil flows through the defined through- hole 24a, 24b, 24c as leakage path to the intake area 14 and in doing so, lubricates as well as cools at least the first component 15-1a, 15-1b, 15-1c of shaft sealing element 15a, 15b, 15c formed as a sealing lip. In addition, lubrication of the bearings 9, 10 is improved.
Since the back pressure and the intermediate pressure prevailing in the back pressure area 13, respectively, are regulated by means of a second expansion device 18 formed as a regulating valve, there is no requirement for a high accuracy of the through- hole 24a, 24b, 24c as the first expansion device 17.
Furthermore, according to Fig. 2a, the device 1 can be formed without a filter element 20, since the centrifugal force generated, when in operation, during the rotation of the drive shaft 6, 6a, 6b as well as the elements moved by the drive shaft 6, 6a, 6b, transports any unwanted particles possibly present outward in the radial direction and thus the through- hole 24a, 24b, 24c cannot clog. If, when the device 1 is at a standstill, as in the case of a pressure equalization during a compressor stop, particles accumulate in front of the through- hole 24a, 24b, 24c, the particles are removed in the aforementioned manner after start-up of the device 1 due to the rotation of the drive shaft 6, 6a, 6b.
Figs. 4a to 4d each illustrate a drive shaft 6b-1, 6b-2, 6b-3 of a first embodiment of a drive shaft-housing connection according to Fig. 3a, with at least one recess 60-1, 60-2 compared to a drive shaft 6a of a scroll compressor without a recess. The groove-shaped recesses 60-1, 60-2 have substantially equal extensions in the axial direction.
The recesses 60-1, 60-2 of Figs. 4b and 4c provided in each case within the drive shafts 6b-1, 6b-2 differ both in the size and in the shape of the cross section formed in the plane oriented perpendicular to the axial direction. While the cross section of the recess 60-1 has a rectangular shape, the cross section of the recess 60-2 has a semicircular form. Here, the recess 60-1 is much wider than the recess 60-2. The recesses 60-1, 60-2 can also have different depths, in particular in the range of 0.01 mm to 0.3 mm.
Compared to the embodiments of the drive shafts 6b-1, 6b-2 of Figs. 4b and 4c, a plurality of recesses 60-2 are provided in the embodiment of the drive shaft 6b-3 according to Fig. 4d. The recesses 60-2 are preferably arranged evenly distributed over the circumference of the surface of the drive shaft 6b-3 and can be in alignment in the axial direction. Alternatively, the recesses are arranged with different lengths and optionally offset in the axial direction. Over the length of the recess 60, 60-1, 60-2 extending in the axial direction it is ensured in each case that in connection with the first component 15-1a and the second component 15-2 of the shaft sealing element 15a a corresponding expansion cross section is formed.
Figs. 5a to 5e each show a shaft sealing element 15b-1, 15b-2, 15b-3, 15b-4 of a second embodiment of a drive shaft-housing connection according to Fig. 3b with at least one contour 150b-1, 150b-2 compared to a shaft sealing element 15a of a scroll compressor without contour from the prior art. The contours 150b-1, 150b-2 formed as a groove-shaped recess in each case have substantially the same extensions in the circumferential direction at least in the area of the inner diameter of the shaft sealing element 15b-1, 15b-2, 15b-3, 15b-4.
The contours 150b-1, 150b-2 of Figs. 5b and 5c provided within the shaft sealing element 15b-1, 15b-2 at the inner lateral surface differ both in the size and in the shape of the cross section formed in the plane oriented perpendicular to the axial direction. While the cross section of the contour 150b-1 has a rectangular shape, the cross section of the recess 150b-2 has a semicircular form. Here, the contour 150b-1 is much wider in the area of the outer radius due to the basic shape of the cross section than the contour 150b-2. The contours 150b-1, 150b-2 can also have different depths, in particular in the range of 0.01 mm to 0.3 mm.
Compared to the embodiments of the shaft sealing elements 15b-1, 15b-2 of Figs. 5b and 5c, a plurality of contours 150b-2, in particular three or four, are provided in the embodiments of the shaft sealing elements 15b-3, 15b-4, according to Figs. 5d and 5e. The contours 150b-2 are each preferably arranged evenly distributed over the circumference of the inner lateral surface of the shaft sealing element 15b-3, 15b-4. The cross section of the contours can have a rectangular shape or can have a semicircular form.
List of reference numerals
1 scroll compressor, device
2 housing
3 stator, fixed spiral
3a base plate of fixed spiral 3
3b wall of fixed spiral 3
4 orbiter, movable spiral
4a base plate of movable spiral 4
4b wall of movable spiral 4
5 working space
6 drive shaft
6a drive shaft
6b, 6b-1, 6b-2, 6b-3 drive shaft
60, 60-1, 60-2 recess of drive shaft
7 axis of rotation
8 intermediate element with additional weight
9 first bearing
10 second bearing
11 guide device
11-1 hole
11-2 pin
12 wall, counter wall
12a sliding element
13 back pressure area, back pressure chamber
14 intake area
15 shaft sealing element
15a shaft sealing element
15b, 15b-1, 15b-2, 15b-3, 15b-4 shaft sealing element
15c shaft sealing element
15-1a, 15-1b, 15-1c first component of shaft sealing element
15-2 second component of shaft sealing element
150b, 150b-1, 150b-2, 150c contour of shaft sealing element
16 orbiter sealing element
17 first expansion device
18 second expansion device
19 flow channel
20 filter element
21 connection channel
22 flow channel
23 sealing surface
24a, 24b, 24c through-hole of sealing surface 23
pH high pressure
pN low pressure
pZ intermediate pressure, contact pressure

Claims (17)

  1. A device for compressing a gaseous fluid, in particular a scroll compressor, having a housing (2) with a wall (12) and a compression mechanism with an immovable stator (3) as well as a movable orbiter (4) which is driven via a drive shaft (6, 6a, 6b, 6b-1, 6b-2, 6b-3), wherein
    - the wall (12) and the orbiter (4) are formed to enclose a back pressure area (13) at least in areas and the wall (12) is formed between the back pressure area (13) and an intake area (14) delimiting the back pressure area (13) from the intake area (14),
    - the drive shaft (6, 6a, 6b, 6b-1, 6b-2, 6b-3) is arranged to project through a hole formed inside the wall (12), wherein, between the drive shaft (6, 6a, 6b, 6b-1, 6b-2, 6b-3) and the wall (12), a shaft sealing element (15, 15a, 15b, 15b-1, 15b-2, 15b-3, 15b-4, 15c) is arranged to seal the back pressure area (13) from the intake area (14),
    wherein, between the drive shaft (6, 6a, 6b, 6b-1, 6b-2, 6b-3) and the shaft sealing element (15, 15a, 15b, 15b-1, 15b-2, 15b-3, 15b-4, 15c), a sealing surface (23) is formed with a through-hole (24a, 24b, 24c) breaking the sealing surface (23) as well as interconnecting the back pressure area (13) and the intake area (14) hydraulically.
  2. The device according to claim 1, characterized in that the drive shaft (6, 6a, 6b, 6b-1, 6b-2, 6b-3) is formed in the shape of a circular cylinder.
  3. The device according to claim 1 or 2, characterized in that the shaft sealing element (15, 15a, 15b, 15c, 15b-1, 15b-2, 15b-3, 15b-4) is formed in the shape of a circular ring.
  4. The device according to claim 3, characterized in that the shaft sealing element (15, 15a, 15b, 15c, 15b-1, 15b-2, 15b-3, 15b-4) is arranged to abut on a lateral surface of the drive shaft (6, 6a, 6b, 6b-1, 6b-2, 6b-3) circumferentially.
  5. The device according to claim 3 or 4, characterized in that the shaft sealing element (15, 15a, 15b, 15c, 15b-1, 15b-2, 15b-3, 15b-4) has a first hollow circular cylinder-shaped component (15-1a, 15-1b, 15-1c) and a second hollow circular cylinder-shaped component (15-2), which are formed integrally as a coherent unit and enclose the drive shaft (6, 6a, 6b, 6b-1, 6b-2, 6b-3) completely in each case.
  6. The device according to claim 5, characterized in that the first component (15-1a, 15-1b, 15-1c) of the shaft sealing element (15, 15a, 15b, 15c, 15b-1, 15b-2, 15b-3, 15b-4) is arranged to form the sealing surface (23) and to abut on a lateral surface of the drive shaft (6, 6a, 6b, 6b-1, 6b-2, 6b-3) circumferentially.
  7. The device according to claim 5 or 6, characterized in that a gap is formed between an inner lateral surface of the second component (15-2) of the shaft sealing element (15, 15a, 15b, 15c, 15b-1, 15b-2, 15b-3, 15b-4) and a lateral surface of the drive shaft (6, 6a, 6b, 6b-1, 6b-2, 6b-3).
  8. The device according to any one of claims 4 to 7, characterized in that the lateral surface of the drive shaft (6b, 6b-1, 6b-2, 6b-3) has at least one recess (60, 60-1, 60-2) which, in the shape of a groove and extending in an axial direction, is formed as a through-hole (24a), wherein an extension of the recess (60, 60-1, 60-2) in the axial direction is greater than an extension of the shaft sealing element (15a) in the axial direction, and the shaft sealing element (15a) abutting on the lateral surface of the drive shaft (6b, 6b-1, 6b-2, 6b-3) is aligned with the recess (60, 60-1, 60-2) in such a way, that the recess (60, 60-1, 60-2) on both sides projects beyond the shaft sealing element (15a) in the axial direction.
  9. The device according to claim 8, characterized in that at least two recesses (60-2) are formed, which are arranged evenly distributed over the circumference of the lateral surface of the drive shaft (6b, 6b-3).
  10. The device according to any one of claims 4 to 7, characterized in that an inner lateral surface of the shaft sealing element (15b, 15b-1, 15b-2, 15b-3, 15b-4, 15c) abutting on the lateral surface of the drive shaft (6, 6a) has at least one contour (150b, 150b-1, 150b-2, 150c) for forming at least one through-hole (24b, 24c).
  11. The device according to claim 10, characterized in that the at least one contour (150b, 150b-1, 150b-2) is formed in the shape of a groove and extending in an axial direction.
  12. The device according to any one of claims 1 to 11, characterized in that the through-hole (24a, 24b) has a substantially rectangular cross section or a substantially semicircular cross section in a plane oriented perpendicularly to an axial direction.
  13. The device according to claim 10, characterized in that the at least one contour (150c) is formed in the shape of a through-hole, in particular with a circular cross section.
  14. The device according to any one of claims 10 to 13, characterized in that at least two contours (150b, 150b-1, 150b-2) are formed, which are arranged evenly distributed over the circumference of the lateral surface of the shaft sealing element (15b, 15b-1, 15b-2, 15b-3, 15b-4).
  15. The device according to any one of claims 1 to 14, characterized in that a first expansion device (17) is formed for expanding the gaseous fluid pressurizing the back pressure area (13) from a level of an intermediate pressure pZ to a level of a low pressure pN within the intake area (14), and a second expansion device (18) is formed for expanding the gaseous fluid from a level of the high pressure pH to the level of the intermediate pressure pZ within the back pressure area (13), and a regulating means or a control device are formed as well.
  16. The device according to claim 15, characterized in that the through-hole (24a, 24b, 24c) is formed as a first expansion device (17).
  17. The device according to claim 15 or 16, characterized in that the second expansion device (18) is formed as a regulating valve.
PCT/KR2021/016387 2020-11-12 2021-11-11 Device for compressing a gaseous fluid WO2022103163A1 (en)

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DE102020129864.1 2020-11-12
DE102020129864.1A DE102020129864A1 (en) 2020-11-12 2020-11-12 Device for compressing a gaseous fluid

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US6347843B1 (en) * 1998-04-22 2002-02-19 Denso Corporation Pump equipment and method for assembling same
US20110140368A1 (en) * 2006-06-21 2011-06-16 Trelleborg Sealing Solutions Germany Gmbh Seal and Seal Arrangement
US20180238191A1 (en) * 2017-02-20 2018-08-23 Bosch Mahle Turbo Systems Gmbh & Co. Kg Bearing housing and an exhaust gas turbocharger with such a housing
JP2018159285A (en) * 2017-03-22 2018-10-11 サンデンホールディングス株式会社 Scroll type compressor
KR20190083565A (en) * 2018-01-04 2019-07-12 엘지전자 주식회사 Motor-operated compressor

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JP2002089463A (en) 2000-09-18 2002-03-27 Toyota Industries Corp Scroll type compressor
KR101642178B1 (en) 2013-07-02 2016-07-25 한온시스템 주식회사 Scroll compressor
DE102016113057B4 (en) 2016-07-15 2019-05-23 Hanon Systems Apparatus for compressing a gaseous fluid having an arrangement for separating a control mass flow and methods for separating the control mass flow
KR102317527B1 (en) 2017-06-15 2021-10-26 엘지전자 주식회사 Scroll compressor
DE102019208680A1 (en) 2019-06-14 2020-12-17 Brose Fahrzeugteile SE & Co. Kommanditgesellschaft, Würzburg Displacement machine based on the spiral principle, especially scroll compressors for a vehicle air conditioning system

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6347843B1 (en) * 1998-04-22 2002-02-19 Denso Corporation Pump equipment and method for assembling same
US20110140368A1 (en) * 2006-06-21 2011-06-16 Trelleborg Sealing Solutions Germany Gmbh Seal and Seal Arrangement
US20180238191A1 (en) * 2017-02-20 2018-08-23 Bosch Mahle Turbo Systems Gmbh & Co. Kg Bearing housing and an exhaust gas turbocharger with such a housing
JP2018159285A (en) * 2017-03-22 2018-10-11 サンデンホールディングス株式会社 Scroll type compressor
KR20190083565A (en) * 2018-01-04 2019-07-12 엘지전자 주식회사 Motor-operated compressor

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