SCROLL COMPRESSOR OF AN ELECTRICAL REFRIGERANT DRIVE AND ELECTRICAL REFRIGERANT DRIVE

Abstract

A scroll compressor of an electrical refrigerant drive contains a housing having a low-pressure chamber, a high-pressure chamber, compression chambers and a counter-pressure chamber. A stationary scroll has a base plate and a spiral wall, the base plate of the stationary scroll delimits the high-pressure chamber. A movable scroll has a base plate and a spiral wall which engages into the spiral wall of the stationary scroll and forms the compression chambers with the spiral wall. The base plate of the movable scroll delimits the counter-pressure chamber. A first fluidic connection is provided which connects the counter-pressure chamber to the radially innermost compression chamber, and the first fluidic connection is located in a positioning region of the radially innermost compression chamber between 75° to 195° following the merge angle.

Claims

1. A scroll compressor of an electrical refrigerant drive, the scroll compressor comprising: a housing having a low-pressure chamber, a high-pressure chamber, compressor chambers and a back pressure chamber; a fixed scroll having a base plate and a spiral wall, wherein said base plate of said fixed scroll delimits said high-pressure chamber; a movable scroll having a base plate and a spiral wall engaging in said spiral wall of said fixed scroll and forming said compressor chambers with said fixed scroll, wherein said base plate of said movable scroll delimits said back pressure chamber; an outlet opening; and a first fluid connection connecting said back pressure chamber to a radially innermost compressor chamber of said compressor chambers which, in a course of a movement of said movable scroll, is coupled to said high-pressure chamber via said outlet opening, wherein said first fluid connection is disposed in a positioning region of said radially innermost compressor chamber between 75° to 195° after a merge angle at which two of said compressor chambers merge to form said radially innermost compressor chamber.

2. The scroll compressor according to claim 1, further comprising a second fluid connection disposed so that it is offset outward, starting from said first fluid connection, by a spiral angle of 320° to 400° and connects said back pressure chamber to a compressor chamber of said compression chambers which is different from said radially innermost compressor chamber.

3. The scroll compressor according to claim 1, wherein said first fluid connection overlaps with said outlet opening at no time in a movement of said movable scroll.

4. The scroll compressor according to claim 2, wherein neither of said first and second fluid connections is coupled to said low-pressure chamber.

5. The scroll compressor according to claim 2, wherein said first and second fluid connections are disposed such that said first and second fluid connections are collectively closed at no time in a movement of said movable scroll.

6. The scroll compressor according to claim 1, wherein said first fluid connection is introduced into said spiral wall of one of said fixed scroll or said movable scroll.

7. The scroll compressor according to claim 1, wherein said spiral wall of one of said movable scroll or said fixed scroll has a stepped axial offset, and said first fluid connection is introduced in a region of said stepped axial offset.

8. The scroll compressor according to claim 1, wherein said first fluid connection is introduced in said fixed scroll.

9. The scroll compressor according to claim 8, wherein said first fluid connection is introduced transversely into said outlet opening.

10. The scroll compressor according to claim 2, wherein all of said first and second fluid connections are introduced into a same scroll being either said fixed scroll or said movable scroll.

11. An electrical refrigerant drive, comprising: power electronics; an electromotive drive; and said scroll compressor according to claim 1 coupled to said electromotive drive as a compressor head.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0078] FIG. 1 is a diagrammatic, sectional view of an electrical refrigerant compressor with a scroll compressor with an integrated back pressure system;

[0079] FIG. 2 is a sectional view of a portion of the scroll compressor;

[0080] FIGS. 3A, 3B are sectional views of the scroll compressor taken along the line of section III-III shown in FIG. 2 at different points in time of the compression process;

[0081] FIG. 4 is a plan view of the orbiting scroll;

[0082] FIGS. 5A, 5B are plan views of the orbiting scroll with a projected compressor chamber;

[0083] FIG. 6 are a series of sectional views of the compression process of the scroll compressor;

[0084] FIG. 7 is a graph showing a shaft angle; pressure graph of the compression process;

[0085] FIG. 8 is a sectional view of a schematic illustration of a primary and a secondary oil circuit in the scroll compressor;

[0086] FIG. 9 is a sectional view of a second embodiment of the scroll compressor;

[0087] FIG. 10 is a sectional view of a third embodiment of the scroll compressor;

[0088] FIG. 11 is a perspective view of the orbiting scroll in Ho. 10;

[0089] FIG. 12 is a sectional view of a fourth embodiment of the scroll compressor;

[0090] FIG. 13 is a sectional view of a fifth embodiment of the scroll compressor; and

[0091] FIG. 14 is a sectional view of a sixth embodiment of the scroll compressor.

DETAILED DESCRIPTION OF THE INVENTION

[0092] Corresponding parts and sizes are always provided with the same reference symbols in all the drawings.

[0093] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a refrigerant drive 2 which is preferably installed as a refrigerant compressor in a refrigerant circuit (not shown in detail) of an air-conditioning system of a motor vehicle. The electromotive refrigerant compressor 2 has an electric (electromotive) drive 4 and a scroll compressor 6 coupled to the latter as a compressor head. The scrod compressor 6 is also referred to below as a compressor 6 for short.

[0094] The drive 4, on the one hand, and the compressor 6, on the other hand, have, for example, a modular structure such that, for example, the drive 4 can be coupled to different compressors 6. A transition region formed between the modules 4 and 6 has a mechanical interface in the form of a bearing plate 8. The compressor 6 is attached to the drive 4 via the bearing plate 8 so that it can be driven.

[0095] The drive 4 has a pot-shaped drive housing 10 with two housing subregions 10a and 10b which are separated from each other in a fluid-tight manner by a monolithically integrated housing partition wall (bulkhead) 10c inside the drive housing 10. The drive housing 10 is preferably produced as a die-cast part from an aluminum material.

[0096] The compressor-side housing subregion is designed as a motor housing 10a for accommodating an electric motor 12. The motor housing 10a is closed on one side by the (housing) partition wall 10c and on the other side by the bearing plate 8. The housing subregion situated on the opposite side of the partition wall 10c is designed as an electronics housing 10b in which power electronics (motor electronics), not shown in detail and which control and/or regulate the operation of the electric motor 12 and hence the compressor 6, are accommodated.

[0097] The electronics housing 10b is closed on an end side of the drive 4 facing away from the compressor 6 by a housing cover (electronics cover) 14. When the housing cover 14 is open, the power electronics are mounted in an electronics compartment 16 formed by the electronics housing 10b and, when the housing cover 14 has been removed, can also be accessed easily for maintenance or repair purposes.

[0098] The drive housing 10 has a (suction gas) inlet or suction port (inflow), not shown in detail, for connection to the refrigerant circuit of the air-conditioning system approximately at the level of the electric motor 12. A fluid, in particular a suction gas, flows via the inlet into the drive housing 10, in particular into the motor housing 10a. The fluid flows from the motor housing 10a through the bearing plate 10 to the compressor 6. The refrigerant is then compressed by means of the compressor 6 and is discharged at a (refrigerant) outlet 18 (outflow) in the bottom of the compressor 6 into the refrigerant circuit of the air-conditioning system.

[0099] The outlet 18 is integrally formed on the bottom of a pot-shaped (compressor) housing 20 of the compressor 6. In the connected state, the inlet here forms the low-pressure or suction side and the outlet 18 the high-pressure or discharge side of the refrigerant compressor 2.

[0100] The in particular brushless electric motor 12 contains a rotor 24 which is coupled non-rotatably to a motor shaft 22 and is arranged so that it can revolve inside a stator 26. The motor shaft 22 is mounted so that it can rotate or revolve by means of two bearings 28. One bearing 28 is here arranged in a bearing seat 30 which is integrally formed on the bottom of the housing or on the partition wall 10c of the drive housing 10. The other bearing 28 is accommodated in the bearing plate 8. The bearing plate 8 here has a sealing ring 32 for sealing with respect to the motor shaft 22.

[0101] As can be seen relatively clearly in conjunction with FIG. 2, the scroll compressor 6 has a movable scroll (scroll part) 34 arranged in the compressor housing 20. It can be coupled to the motor shaft 22 of the electric motor 12 by means of a balance weight 36 as a swing link or eccentric via two joining pins or shaft journals 38, 40. The shaft journal 38 is here configured as a so-called eccentric pin and the shaft journal 40 as a so-called limiter pin.

[0102] The balance weight 36 is mounted in a bearing 42 held in the movable scroll 34. The movable scroll 34 is driven in orbiting fashion during the operation of the scroll compressor 6.

[0103] The scroll compressor 6 also has a rigid fixed scroll (scroll part) 44, i.e. one fastened in the compressor housing 20 so that it is fixed to the latter. The two scrolls (scroll parts) 34, 44 engage in each other with their helical or spiral-shaped spiral walls (scroll walls, scroll spirals) 34a, 44a which rise axially from the respective base plate 34b, 44b. The spiral walls 34a, 44a are provided with reference symbols in the drawings only by way of example. The scroll 44 furthermore has a peripheral delimiting wall 44c forming the outer periphery.

[0104] The scrolls 34, 44 are connected to the motor space of the motor housing 10a via a suction or low-pressure chamber 46 of the compressor housing 22. When the compressor is operating, the fluid is conveyed from the low-pressure chamber 46 to a high-pressure chamber 48 of the compressor housing 20. An oil separator 50 configured as a cyclone separator is arranged in the high-pressure chamber 48. The separated oil is conveyed back via an oil return line 52 in order to lubricate moving parts (FIG. 8).

[0105] A flapper valve (finger spring valve) 54 is arranged between the scroll 44 and the high-pressure chamber 48, i.e. on the bottom of the base plate 44b, as a cover or closing part by means of which a central high-pressure-side outlet opening 56 of the scroll part 44 is covered. A flapper valve 54 is here understood in particular to be a non-return valve which opens in the direction of passage purely because of pressure differences on the two sides of the valve and with no other driving means, and which closes again automatically, i.e. covers the outlet opening 56.

[0106] The outlet opening 56 is also referred to below as the main outlet port. Two further outlet openings 58 (FIGS. 3A, 3B) are provided as so-called pre-outlets or auxiliary outlets, radially spaced apart from the main outlet port 56. The outlet ports 58 are also referred to below as secondary valve ports.

[0107] The flapper valve 54 is provided, on one hand, as the main valve for the outlet opening 56 and, on the other hand, as a pre-outlet valve or auxiliary outlet valve for the outlet openings 58 of the scroll part 44, by means of which over-compression of the refrigerant 2 during operation of the compressor is avoided. This ensures a pressure-regulated discharge of refrigerant from the outlet openings 56, 58.

[0108] A back pressure chamber 60, part of a back pressure system which is not described in detail, is situated between the A-side bearing plate 8 (center plate) and the movable scroll 34. The back pressure chamber 60 is delimited in the compressor housing 20 by the base plate 20 of the movable scroll 34. The back pressure chamber 60 extends in some regions into the base plate 34b of the movable scroll 34. The back pressure chamber 60 is sealed with respect to the base plate 34b by means of a seal 62.

[0109] When the refrigerant drive 2 is operating, the refrigerant is introduced into the drive housing 10 via the inlet and from there into the motor housing 10a. This region of the drive housing 10 forms the suction or low-pressure side of the scroll compressor 6. The refrigerant can be prevented from penetrating into the electronics compartment 16 by means of the housing partition wall 10b. Inside the drive housing 10, the refrigerant/oil mixture is drawn along the rotor 24 and the stator 26 through an opening to the suction or low-pressure chamber 46 of the scroll compressor 6. The mixture of refrigerant and oil is compressed by means of the scroll compressor 6, wherein the oil is used to lubricate the two scrolls 34, 44 such that friction is reduced and consequently efficiency is increased. The oil is also used for sealing in order to prevent the uncontrolled escape of the refrigerant situated between the two scrolls (scroll parts) 34, 44.

[0110] The compressed mixture of refrigerant and oil is channeled via the central main outlet port 56 in the base plate 44b of the fixed scroll 44 into the high-pressure chamber 48 inside the compressor housing 20. The mixture of refrigerant and oil is set in rotational motion inside the oil separator 50, wherein, because of its increased inertia and increased mass, the heavier oil is channeled to the walls of the oil separator 50 and collects under the effect of gravity g in a lower region of the oil separator 50, while the refrigerant is discharged upward or laterally through the outlet 18. The oil is channeled back to the electric motor 12 by means of the oil return line 52 which opens out in the lower or lateral region of the oil separator 50. In other words, the high-pressure chamber 48 is fluidically connected to the low-pressure side by means of the oil return line 52. The oil return line 52 is configured, for example, as a bypass duct with a choke member in the form of an orifice (FIG. 8).

[0111] “Axial” or an “axial direction A” is understood here and below in particular to mean a direction parallel (coaxial) to the axis of rotation of the electric motor 12, i.e. in the longitudinal direction of the refrigerant drive 2. Correspondingly, “radial” or a “radial direction R” is understood here and below to mean a direction, oriented perpendicular (transversely) to the axis of rotation of the electric motor 12, along a radius of the electric motor 12 or the scroll parts 34, 44. “Tangential” or a “tangential direction T” is understood here and below to mean in particular a direction along the periphery of the electric motor (peripheral direction, azimuthal direction) or of the scroll parts 34, 44, i.e. a direction perpendicular to the axial direction and to the radial direction. The direction of gravity is labeled g and illustrated by way of example in the drawings.

[0112] In the mounted state of the compressor 6, the spiral body or the spiral wall 34a of the movable scroll part 34 engages into the free or intermediate spaces of the spiral wall 44a of the fixed scroll part 44. Compressor chambers, the volumes of which are altered when the compressor is operating, are formed between the scrolls 34, 44, i.e. between their scroll walls or scroll spirals 34a, 44a and the base plates 34b, 44b. A distinction is also made below between suction chambers S, compression chambers K, and discharge chambers D of the compressor chambers, wherein the respective compression path is identified in FIGS. 3A and 3B by a subscript 1 or 2.

[0113] As can be seen in FIG. 3A, the suction chambers S are here open on the low-pressure side, i.e. leading to the low-pressure chamber 46. As soon as the suction chambers S are closed by the orbiting movement of the scroll 34, they become compression chambers K (FIG. 3B), the sickle-shaped volumes of which are successively compressed in the course of the orbiting movement toward the center of the spiral. The angular position of the motor shaft 22 at which the suction chambers S are closed is also referred to below as the 0° position. The two radially innermost compression chambers K here form the discharge chambers D. The discharge chambers D interconnect or merge to form a common outlet chamber DD (FIG. 3a) which delivers the compressed refrigerant/oil mixture into the high-pressure chamber 48 by means of the outlet opening 56. The angular position of the motor shaft 22 at which the discharge chambers D merge to form the outlet chamber DD is also referred to below as the merge angle or merging system.

[0114] The back pressure system according to the invention enables flexible and effective adjustment of the pressure in the back pressure chamber 60. In the exemplary embodiment of FIGS. 1 to 8, the back pressure chamber 60 is connected for this purpose to the compressor chambers via two fluid connections 64, 66. In the case of a scroll with a scroll length of 720°, it is suitable that more than two fluid connections are provided (utilizing the symmetry). Each fluid connection here connects a different compressor chamber to the back pressure chamber 60, wherein none of the fluid connections 64, 66 communicate with the low-pressure chamber 46. The fluid connections 64, 66 are here introduced into the base plate 34b of the orbiting scroll 34 as axial bores.

[0115] The positioning of the fluid connections 64, 66 is explained in detail below with the aid of FIGS. 4 to 6, wherein the fluid connections 64, 66 are not shown explicitly in FIG. 4, FIG. 5A, and FIG. 5B. The radially outer spiral end 68 of the spiral wall 34a is described below with a spiral angle of 0°. If a clock hand were to be turned counterclockwise from the center of the spiral 70 (the center of the spiral is not necessarily at the center of the base plate), it would travel over the whole spiral contour of the spiral wall 34a from outside to inside (FIG. 4). The spiral wall section 72 which corresponds to a spiral angle of 360°, and the spiral wall section 74 which corresponds to a spiral angle of 720°, are also shown in FIGS. 4 and 5.

[0116] Because it is intended that none of the fluid connections 64, 66 are connected to the suction side, the radially outer fluid connection 66 is arranged in an angular or tolerance range 76a which corresponds to a spiral angle of between 360°±45°, i.e. 315° to 405°. The tolerance range 76a of the positioning results from the fluid connection 66 being covered by the spiral tip of the fixed scroll 44, i.e. by the axial contact surface of the spiral wall 44a, in the course of the orbiting movement. For a spiral wall thickness of up to 90°, a quarter of a shaft revolution can thus be covered.

[0117] The fluid connection 66 can be positioned both on the concave and on the convex side of the spiral wall 34a, wherein the convex arrangement is arranged offset or mirrored by 180°. This means that a second tolerance range 76b is provided for the convex arrangement, within which the radially outer fluid connection 66 is arranged at a spiral angle of between 540°±45°, i.e. 495° to 595°. Depending on which side is chosen, the fluid connection 66 is situated in one of the two compression paths.

[0118] A radial spacing 78 of the fluid connection 66 from the flank of the spiral wall 34a is here no larger than the wall thickness of the spiral wall 44a in the corresponding region because otherwise the fluid connection 66 would come into contact with one of the discharge chambers D.

[0119] The fluid connection 64 is here arranged in the region of the radially innermost compressor chamber, i.e. in the region of the discharge chambers D or the outlet chamber DD. The first fluid connection 64 is thus arranged inside the (radially) innermost compressor chamber from which the compressed fluid or the compressed refrigerant is discharged through the main outlet port into the high-pressure chamber.

[0120] With regard to the positioning of the inner fluid connection 64, no direct specification of the angle of the spiral angle, such as for example 720°, is possible because the influence of the main outlet port 56 and a tip cut 80 plays an important role here. Furthermore, no “jump” or switch to another compression chamber can take place in the inner region of the scroll compressor 6 when the spacing from the spiral flank is too large because it is already the innermost compression chamber.

[0121] The positioning here relates to a positioning region which is characteristic for all scroll compressors, namely in the region of the outlet chamber DD. This region is created after the two innermost discharge chambers D have merged and is continuously fluidically connected to the main outlet port 56.

[0122] A compressor process of the scroll parts 34, 44 is shown in four partial illustrations 82, 84, 86, 88 in FIG. 6, wherein each partial illustration 82, 84, 86, 88 corresponds to a clockwise 90° revolution of the shaft, i.e. a quarter of the orbiting cycle of the scroll 34. The partial illustrations 82, 84, 86, 88 show a view in section of the scroll compressor 6 showing the fixed scroll 44, wherein the fluid connections 64, 66 are shown as projections, and wherein the circular movement of the fluid connections 64, 66 due to the orbiting movement of the scroll 34 is shown in dashed lines.

[0123] In FIG. 6, the movement of the fluid connection 64 intersects the outlet opening 56. In a preferred embodiment, however, the fluid connection 64 is arranged with no overlap such that the movement at no time touches the outlet opening 56.

[0124] FIG. 6 shows in the partial illustration 84 the moment shortly before the merging of the discharge chambers D to form the outlet chamber DD. The partial illustration 88 shows this region at a 180° revolution of the shaft. The significant positioning region for the fluid connection 64 in order to be able to monitor the majority of a discharge chamber D and the outlet chamber DD is provided by the silhouette of the outlet chamber DD at 90°±15° after the so-called merge angle, i.e. the angular position at which the discharge chambers D from the partial illustration 84 merge. This region is shown in the illustration in FIG. 5A as a projection onto the base plate 34. An advantageous positioning of the fluid connection 64 is situated in a positioning region of the outlet chamber DD of 180° after the merge angle, as shown in the partial illustration 88 in FIG. 6 and in the projected illustration in FIG. 5B. The positioning region of 180° after the merge angle (FIG. 5B) is here a subregion of the positioning region 90° after the merge angle (FIG. 5A).

[0125] This means that the fluid connection 64 is arranged at an angular position within 90° to 180° after the merge angle in the outlet chamber DD. The subsequent (second) fluid connection 66 is arranged at a position which at a spiral angle of 320° to 400° further outward on the spiral 34a. The fluid connection 66 is thus situated in a region in which it establishes a connection to the compression chambers K. The fluid connections 64, 66 are here arranged in such a way that the fluid connections 64, 66 are not covered or closed at any time in the orbiting movement of the movable scroll 34. In other words, preferably at least one fluid connection 64, 66 is open at any point in time.

[0126] The two fluid connections 64, 66 are active in respective different compression regions during a compression cycle. In particular, essentially the whole compression cycle (FIG. 6) is actively fluidically connected to the back pressure chamber 60. The diameters of the fluid connections 64, 66 are here weighted with the cross-sectional areas of the associated compressor chambers. This means that the inner fluid connection 64 has a smaller diameter than the subsequent outer fluid connection 66.

[0127] The functioning of the back pressure system is explained in detail below with the aid of FIG. 7. In the schematic shaft angle/pressure graph in FIG. 7, a shaft angle WW of the motor shaft 22 is plotted in radians horizontally, i.e. on the abscissa (x-axis) and a pressure p, for example in bars (bar), is plotted on the vertical ordinate axis (y-axis). Three horizontal lines 90, 92, 94 which identify different pressure levels are shown in FIG. 7. The line 90 corresponds to a high-pressure level of the high-pressure chamber 48, the line 92 shows a back pressure level of the back pressure chamber 60, and the line 94 shows a low-pressure level of the low-pressure chamber 46.

[0128] Three compression curves 96, 98, 100 for successive compression cycles are shown in the graph in FIG. 7, wherein the compression curve 98 represents a current compression cycle, and wherein the compression curve 96 shows a preceding compression cycle, and the compression curve 100 shows a subsequent compression cycle. The region 102 of the curve 96 which is illustrated by a dotted line corresponds to over-compression.

[0129] The outer fluid connection 66 is open in the region labelled 104 of the compression curve 98 such that there is an active fluidic connection between a compression chamber K and the back pressure chamber 60. A backflow phenomenon is shown schematically in the region 106, wherein the merge angle is present, i.e. the discharge chambers D merge to form the outlet chamber DD, at the point 108. The inner fluid connection 64 is open in the region 110 such that an active fluid connection exists between a discharge chamber D or the outlet chamber DD and the back pressure chamber 60.

[0130] The two fluid connections 64, 66 are active in respective different compression regions during a compression cycle 98. Depending on the high-pressure level 90 and the low-pressure level 94, a specific back pressure is required in order to ensure the axial force compensation of the back pressure system. Refrigerant mass flows 112 (a refrigerant mass flow also always means a certain proportion of an oil mass flow) are channeled in and out of the back pressure chamber 60 through the two fluid connections 64, 66. The mass flows 112 are shown as vertical arrows in FIG. 7.

[0131] The propelling force is here the difference in pressure between the compression chambers K, D, DD and the back pressure chamber. If the pressure of a fluidically connected compression chamber is less than that in the back pressure chamber, refrigerant flows from the back pressure chamber into the compression chamber (the region 104 and start of the region 110). If the reverse is the case, refrigerant flows from the compression chamber into the back pressure chamber.

[0132] An internal oil circuit which delivers oil to the bearings 28, 42 in the back pressure chamber 60 and thus lubricates them, is implemented by the fluid connections 64, 66. This is explained in detail below with the aid of FIG. 8.

[0133] When the compressor is operating, essentially two oil circuits 114, 116, which are shown schematically in FIG. 8 with the aid of arrows, are formed in the scroll compressor 6. In the oil circuit 114, which is also referred to as the primary circuit, the oil is separated inside an oil separator 50 of the high-pressure chamber 48 and returned to the suction side or low-pressure chamber 46 via a separate path of the return line 52.

[0134] A secondary oil circuit (secondary circuit) 116 which ensures the lubrication of the bearings 28, 42 by the oil/refrigerant mixture is created by the fluid connections 64, 66. The circuit 116 is here runs inside the scroll parts 34, 44 in the direction from the fluid connection 66 to the fluid connection 64, i.e. from out to in. In the back pressure chamber 60, the oil is returned back into the outer compression chamber where it effects additional sealing of the leakage gaps.

[0135] A second exemplary embodiment of the back pressure system or the scroll compressor 6 is shown in FIG. 9. In this embodiment, the scroll 34 has three fluid connections 64, 66, and 118 configured as bores in the base plate 34b such that (without utilizing the symmetry) at least one fluid connection is provided every or per 360° of spiral angle. As a result, each compression chamber K, D, DD of the scroll spirals is constantly fluidically connected to the back pressure chamber 60 such that, in the case of correct weighting of the connection diameters or cross-sectional areas of the fluid connections 64, 66, 118 to the axial cross-sectional areas of the compression chambers, a back pressure results in the back pressure chamber 60 which enables optimal axial force compensation.

[0136] The fluid connections 66 and 118 are arranged symmetrically relative to each other. In other words, the fluid connections 66, 118 are distributed symmetrically over the compression paths of the scroll compressor 6. As a result, symmetrical recirculation of the mass flow is made possible such that a more uniform pressure distribution is effected in the compressor chambers.

[0137] FIGS. 10 and 11 show a second embodiment of the scroll compressor 6 or the back pressure system in which two fluid connections 64, 66 are provided, wherein the inner fluid connection 64 is introduced as a bore into the spiral wall 34a and the outer fluid connection 66 is introduced as a bore into the base plate 34b.

[0138] The fluid connection 64 is arranged, for example, in the region of the tip cut 80 or a wave guide 120. In the exemplary embodiment shown in FIG. 11, the fluid connection 64 is introduced into the wave guide 120, designed as a stepped axial offset, of the spiral wall 34a which is arranged next to the tip cut 80. At no time in the operation of the compressor or the orbiting movement does a spiral flank or spiral wall 44a move across the wave guide 120 and the latter is therefore never closed. In other words, the fluid connection 64 is always open. This prevents particles from being pushed in when there is movement across the fluid connection 64.

[0139] A third embodiment of the scroll compressor 6 or the back pressure system is shown in FIG. 12. In this embodiment, the fluid connections 64, 66 are introduced into the radial flanks of the spiral wall 34a. The fluid connections 64, 66 are here each configured as two bores which open into each other. The bores which are oriented toward the compressor chambers are here introduced obliquely into the spiral wall 34a, wherein these bores each open into an axial or perpendicular bore of the base plate 34b which is introduced into the base plate 34b from the side on which the back pressure chamber is situated.

[0140] FIG. 13 shows a fourth embodiment in which the fluid connection 64 is introduced into the fixed scroll 44 and the fluid connection 66 is introduced into the orbiting scroll 34. The fluid connection 64 is here configured as three bores 122, 124, 126 which open into one another. The first bore is introduced radially and axially obliquely into the base plate 44b from its outer periphery and opens into the outlet opening 56. The bore is here closed by means of a plug 128 situated radially on the outside. The axial bore 124 is introduced partly into the delimiting wall 44c and partly into the bearing plate 8. The radial bore 126 extends from the back pressure chamber 60 to the bore 124.

[0141] A fifth exemplary embodiment of the scroll compressor 6 or the back pressure system is shown in FIG. 14 in which, in order to improve the robustness against particles, a filter component 130 is introduced into each of the fluid connections 64, 66. The filter components 130 are configured, for example, as fine filter fabrics (for example, Betamesh with a 40 μm mesh size). As a result, it is possible for the diameters of the fluid connections 64, 66 to be configured as smaller. For example, the fluid connections 64, 66 can have a diameter of approximately 0.1 mm, wherein the fluid connection 66 preferably has a larger diameter than the fluid connection 64.

[0142] Additionally or alternatively, it is, for example, possible to introduce a combination part consisting of a filter and choke geometry into the scroll components 34, 44 in order to improve the robustness against particle clogging.

[0143] The invention is not limited to the above-described exemplary embodiments, Instead, other variants of the invention can also be derived therefrom by a person skilled in the art without going beyond the subject of the invention. In particular, all the individual features described in connection with the exemplary embodiments can also be combined with one another in a different fashion without going beyond the subject of the invention.

[0144] Thus, all the alternative embodiments can be implemented analogously both in the orbiting scrod 34 and in the fixed scroll 44, or vice versa. The positioning conditions apply for the scroll 44 and the scroll 34 equally. Furthermore, the fluid connections can also be introduced so that they are distributed over the scrolls 34, 44 and are thus implemented with some in the movable scroll 34 and some in the fixed scroll 44. The essential thing is that the fluid connection 64 is arranged in a positioning region of the outlet chamber OD between 90°±15° to 180°±15°, in particular between 90° to 180°, preferably approximately 180°, after the merge angle.

[0145] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0146] 2 refrigerant drive [0147] 4 drive [0148] 6 scroll compressor [0149] 8 bearing plate [0150] 10 drive housing [0151] 10a motor housing [0152] 10b electronics housing [0153] 10c partition wall [0154] 12 electric motor [0155] 14 housing cover [0156] 16 electronics compartment [0157] 18 outlet [0158] 20 compressor housing [0159] 22 motor shaft [0160] 24 rotor [0161] 26 stator [0162] 28 bearing [0163] 30 bearing seat [0164] 32 sealing ring [0165] 34 scroll [0166] 34a spiral wall [0167] 34b base plate [0168] 36 balance weight [0169] 38 shaft journal [0170] 40 shaft journal [0171] 42 bearing [0172] 44 scroll [0173] 44a spiral wall [0174] 44b base plate [0175] 440 delimiting wall [0176] 46 low-pressure chamber [0177] 48 high-pressure chamber [0178] 50 oil separator [0179] 52 oil return line [0180] 54 flapper valve [0181] 56 outlet opening/main outlet port [0182] 58 outlet opening/secondary valve port [0183] 60 back pressure chamber [0184] 62 seal [0185] 64 fluid connection [0186] 66 fluid connection [0187] 68 spiral end [0188] 70 spiral center [0189] 72 spiral wall section [0190] 74 spiral wall section [0191] 76a, 76b tolerance range [0192] 78 spacing [0193] 80 tip cut [0194] 82, 84, 86, 88 partial illustration [0195] 90, 92, 94 line [0196] 96, 98, 100 compression curve [0197] 102 region [0198] 104, 104′ region [0199] 106 region [0200] 108 point [0201] 110, 110′ region [0202] 112 arrows [0203] 114 oil circuit/primary circuit [0204] 116 oil circuit/secondary circuit [0205] 118 fluid connection [0206] 120 wave guide/offset [0207] 122, 124, 126 bore [0208] 128 plug [0209] 130 filter component [0210] A axial direction [0211] R radial direction [0212] T tangential direction [0213] g gravity [0214] S suction chamber [0215] K compression chamber [0216] D discharge chamber [0217] DD outlet chamber [0218] WW shaft angle [0219] P PRESSURE