Scroll compressor for compressing high-pressure refrigerant

Abstract

The invention relates to a scroll compressor for compressing high-pressure refrigerant, in particular for use in the automotive sector, having a drive chamber (10) in which a drive (11) is located, and having a compression chamber (20) which is separated from the drive chamber (10) by a housing intermediate wall (15) and in which an orbiting displacer spiral (21) is located which engages in a counter-spiral (22) in such a way that at least one variable compression chamber (30) for compressing the high-pressure refrigerant is formed between the displacer spiral (21) and the counter-spiral (22), an axial gap which is sealed by a tip seal (23, 24) being formed between the displacer spiral (21) and the counter-spiral (22). A pressure chamber (40) is formed between the displacer spiral (21) and the housing intermediate wall (15), the pressure chamber being at least temporarily fluidically connectable or fluidically connected to the compression chamber (30). The invention further relates to a vehicle air-conditioning system having such a scroll compressor.

Description

[0001] Scroll compressor for compressing high-pressure refrigerant

[0002] The invention relates to a scroll compressor for compressing high-pressure refrigerant according to the preamble of claim 1. The invention further relates to a vehicle air conditioning system with such a scroll compressor. A scroll compressor of the type mentioned above is known, for example, from EP 3 309 399 A1.

[0003] EP 3 309 399 A1 describes a scroll compressor suitable for compressing a high-pressure refrigerant, specifically carbon dioxide or R744. The scroll compressor has a drive chamber containing a drive unit and a compression chamber separated from the drive chamber by a partition wall. The compression chamber contains an orbiting displacer spiral that engages with a stationary counter-spiral. This creates variable compression chambers between the displacer spiral and the counter-spiral, whereby the movement of the orbiting displacer spiral compresses the high-pressure refrigerant introduced into the compression chambers. An axial gap is formed between the displacer spiral and the counter-spiral. To prevent refrigerant from escaping via the displacer spiral or the counter-spiral, a gap is created.Since the counter-spiral flows and thus leaves the compression chamber, a tip seal is provided to seal the gap between the displacer spiral and the counter-spiral.

[0004] The compression of carbon dioxide generates high compression pressures, particularly exceeding 40 bar, which act on the displacer spiral and the counter-spiral. The resulting axial forces place a particular load on the displacer spiral and an axial sliding bearing located between the displacer spiral and the housing partition. Due to these high axial forces, the axial sliding bearing is subject to significant wear.

[0005] The object of the invention is to provide a scroll compressor for compressing high-pressure refrigerants, which exhibits low wear and simultaneously ensures a good seal between the displacement spiral and the counter-spiral. Furthermore, it is an object of the invention to provide a vehicle air conditioning system with such a scroll compressor.

[0006] According to the invention, this problem is solved with regard to the scroll compressor by the subject matter of claim 1 and with regard to the vehicle air conditioning system by the subject matter of claim 13.

[0007] Specifically, the problem is solved by a scroll compressor for compressing high-pressure refrigerants, particularly for automotive applications, which has a drive chamber in which a drive unit is located. Furthermore, the scroll compressor has a compression chamber separated from the drive chamber by a housing partition, in which an orbiting displacer spiral is arranged. The orbiting displacer spiral engages with a counter-spiral such that at least one variable compression chamber for compressing the high-pressure refrigerant is formed between the displacer spiral and the counter-spiral. An axial gap is formed between the displacer spiral and the counter-spiral, which is sealed by a tip seal. According to the invention, a pressure chamber is formed between the displacer spiral and the housing partition, which is fluidly connectable to or fluidly connected with the compression chamber, at least temporarily.

[0008] The present invention thus supplements a scroll compressor, whose displacement spiral and counter-spiral are sealed against each other by a tip seal, with a pressure chamber between the displacement spiral and the housing partition. Such a pressure chamber is similar to a technology also known as a backpressure system. The pressure chamber, which can be at least temporarily fluidically connected to the compression chamber, can therefore be pressurized with the refrigerant undergoing compression. The pressure of the refrigerant generated in the compression chamber is thus used to exert a back pressure on the displacement spiral, thereby reducing the load on the axial bearing.

[0009] Generally, high pressures are generated in the compression chamber, causing the displacer spiral to be forced towards the housing partition. The pressure chamber then generates a counter-pressure that acts axially against the compression pressure between the displacer spiral and the counter-spiral. This reduces the contact pressure of the displacer spiral against the housing partition, thus reducing wear, which occurs particularly in the area of ​​an axial sliding bearing between the housing partition and the displacer spiral.

[0010] In a scroll compressor, the refrigerant to be compressed is introduced into the compression chamber at a radially outer point of the displacement spiral. It then flows spirally through the compression chamber to the center of the counter-spiral and is compressed along the way. Since the refrigerant pressure increases from the radially outer inlet to the radially inner outlet, different pressure differentials act on the compression chambers of the displacement spiral and the counter-spiral in the radial direction. A tip seal is used to seal these large pressure differences.

[0011] In general, the displacer spiral can be provided with a first tip sealing element that seals an axial gap between the displacer spiral and a counter-spiral base. Furthermore, the counter-spiral can have a second tip sealing element that seals against a displacer spiral base, in particular an axial gap between the counter-spiral and the displacer spiral base. The axial gap between the displacer spiral and the counter-spiral can therefore be formed, on the one hand, between a free end face of spiral walls of the displacer spiral and the counter-spiral base, and on the other hand, between a free end face of spiral walls of the counter-spiral and the displacer spiral base.The tip seal, which seals this axial gap, can in particular be designed in two parts and comprise a first tip seal element and a second tip seal element, wherein the first tip seal element is associated with the displacer spiral and a second tip seal element is associated with the counter spiral.

[0012] In a preferred embodiment of the invention, the displacement spiral has at least one through-channel that establishes a fluid connection between the compression chamber and the pressure chamber. The through-channel is preferably adapted so that the pressure chamber can be pressurized with high-pressure refrigerant from the compression chamber. The through-channel thus enables the transfer of the pressure generated in the compression chamber to the pressure chamber, so that the pressure can act accordingly on the displacement spiral. In particular, the pressure acts between the displacement spiral and the housing partition.By forming the through-channel in the displacement spiral, it is also ensured that a sufficiently high pressure, generated by the compression in the compression chamber, reaches the pressure chamber and can effect the corresponding force reduction on the displacement spiral in order to reduce frictional forces in the area of ​​the axial sliding bearing.

[0013] In a further preferred embodiment of the scroll compressor according to the invention, the through-channel is formed in a section of the displacement spiral in such a way that, in the activated state of the scroll compressor, the through-channel is open when 70%–100%, in particular 90%–100%, and in particular 95%, of the relative compression chamber volume is reached, and remains open during a subsequent rotation of the displacement spiral by a rotation angle of 120°–360°, in particular 255°–315°, and in particular 270°. In this embodiment, it is particularly preferred if the displacement spiral has a single, i.e., only one, through-channel.

[0014] Generally, the through-channel is preferably formed in a displacement spiral base. The displacement spiral walls are preferably free of through-passes.

[0015] The arrangement of the through-channel in a section, particularly a bottom section, of the displacement spiral, such that the through-channel opens at a specific compression chamber volume, essentially means that the through-channel is not covered by the spiral element or a spiral wall of the counter-spiral in this open state. Rather, in the open state, the through-channel provides a free fluid connection between the compression chamber and the pressure chamber. The invention particularly provides that the open state of the through-channel is maintained for a specific time or over a specific rotation angle of the displacement spiral. In other words, after the through-channel has opened, the displacement spiral can be rotated by a further 120°–360°, particularly a further 255°–315°, and especially a further 270°, while the through-channel remains open.The zero point of the rotation angle, i.e., a rotation angle of 0°, occurs when compression begins between the displacer spiral and the counter-spiral. The starting point of compression is therefore essentially the 0° angle alignment. The previously described design of the displacer spiral, and in particular the positioning of the through-channel, are advantageous because the pressure in the pressure chamber can be precisely controlled. The pressure is adjusted by the position of the through-channel so that a sufficient counterforce from the pressure chamber acts on the displacer spiral to counteract wear-related degradation. This counterforce is preferably set or adjustable to reduce the frictional force exerted by the displacer spiral on the axial sliding bearing, thus minimizing wear on the axial sliding bearing.The counterforce is preferably set so that a constant contact between the displacer spiral and the housing partition is maintained in order to ensure good guidance of the displacer spiral by the axial sliding bearing.

[0016] In one embodiment of the invention, the through-channel in the displacement spiral is arranged such that, during operation, the orbiting motion of the displacement spiral causes the through-channel to be temporarily located, at least partially, in a first compression chamber and subsequently, at least partially, in a second compression chamber. In this embodiment, it is preferred that only a single through-channel is formed in the displacement spiral, particularly in the base of the displacement spiral. Preferably, at least two compression chambers, namely a first compression chamber and a second compression chamber, are formed between the displacement spiral and the counter-spiral. Both compression chambers are variable, meaning their volume changes due to the rotation of the orbiting displacement spiral.In particular, the compression chambers migrate radially inwards due to the orbiting motion of the displacement spiral, thereby reducing their volume. The pressure in the compression chambers increases, thus compressing the high-pressure refrigerant. At the center of the counter-spiral, the compression chambers merge and dissolve. The high-pressure refrigerant is then expelled through an opening in the counter-spiral.

[0017] The through-channel moves along a defined path due to the orbiting motion of the displacer spiral. This defined path of the through-channel overlaps with the first and second compression chambers. This overlap can be adjusted so that the through-channel is temporarily located, at least partially, in the first and then in the second compression chamber. In this way, a fluid connection is established with the pressure chamber in each case, with the fluid connection existing with the first compression chamber on one side and with the second compression chamber on the other. The counterforce on the displacer spiral can be adjusted by positioning the through-channel. The counterforce is preferably set or adjustable to reduce the frictional force exerted by the displacer spiral on the axial sliding bearing, thereby reducing wear on the axial sliding bearing.The counterforce can be adjusted so that a constant contact between the displacer spiral and the housing partition is maintained to ensure good guidance of the displacer spiral by the axial sliding bearing.

[0018] Alternatively or additionally, the displacement spiral can have a first and a second through-channel. The first through-channel can be located primarily in a central section, and the second through-channel in an initial region of the displacement spiral. Both through-channels are preferably arranged in the base of the displacement spiral. This variant allows for alternative pressure adjustment in the pressure chamber to create back pressure on the displacement spiral and thus reduce wear. The variant with two through-channels therefore provides an alternative operating principle, although the effect is similar to that of the variants mentioned above.

[0019] In a preferred embodiment of the scroll compressor according to the invention, the displacement spiral slides over a center plate arranged between the housing partition and the displacement spiral. The axial sliding bearing can be arranged between the center plate and the displacement spiral. The center plate can essentially be designed as an additional element of the housing partition or rest on the housing partition. The center plate, also called the "center plate," is preferably formed by a flat plate, which is characterized in particular by a flat surface. The displacement spiral slides on this flat surface during its orbiting movement. Therefore, the center plate is preferably made of a material that offers low sliding friction.

[0020] The axial sliding bearing can be formed, in particular, by a corresponding sliding ring arranged in or on the base of the displacer spiral and between the displacer spiral and the central plate. Preferably, the axial sliding bearing is located in a radially outer region of the displacer spiral base.

[0021] The displacer spiral can further have several cylindrical blind holes in its base region, each of which interacts with pins arranged in the housing partition to form an anti-rotation mechanism. In general, an anti-rotation mechanism can thus be arranged between the intermediate plate and the displacer spiral. A preferred variant of such an anti-rotation mechanism is a so-called pin-ring system. In this system, the displacer spiral includes corresponding blind holes with a circular diameter in its base, with corresponding pins formed on the intermediate plate that engage in the blind holes in the base of the displacer spiral. The pins, together with the blind holes, prevent the displacer spiral from rotating. Instead, the pin-ring system forces the displacer spiral into an orbiting motion. Other embodiments of anti-rotation mechanisms are also possible.

[0022] With regard to the tip seal, it is preferably provided that it is arranged such that it covers, preferably exclusively, closed component areas. In other words, it is provided that the tip seal, and in particular both tip seal elements, slide over surfaces of the displacement spiral or the counter spiral that are free of openings. In this way, continuous sealing is ensured. Furthermore, this ensures that the tip seal only rubs against smooth surfaces, which minimizes wear on the tip seal and also ensures a uniform seal across its entire length.

[0023] Generally, it is advantageous if the tip seal is made of or consists of a plastic material. Materials such as polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), or polyetheretherketone (PEEK) are particularly preferred. The plastic material may be enriched with fillers.

[0024] Furthermore, the tip seal may have a thickness between 1 mm and 3 mm, particularly 2 mm. In this context, thickness refers to the height of the tip seal, extending from the respective spiral wall of the displacer spiral or counter spiral to the opposite base of the counter spiral or displacer spiral. With regard to the axial sliding bearing, it is advantageous if it also comprises or consists of a plastic material. Preferably, plastics such as polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyetherketone (PEK), or polyaryletherketone (PAEK) are used for the axial sliding bearing. It is also preferred if such plastic materials are enriched with fillers. Furthermore, it is conceivable to use a plastic material made from a combination of the aforementioned plastics.

[0025] Preferably, the axial sliding bearing has a rectangular cross-section. The rectangular cross-section preferably has a long and a short side, with the aspect ratio between the short and long sides preferably being between 0.2 and 0.6. The long side makes contact with the displacer spiral or the center plate. The short side forms the radial outer circumferential surface or the radial inner circumferential surface of the axial sliding bearing.

[0026] In a preferred embodiment, the scroll compressor is generally configured to compress high-pressure refrigerants, particularly CO2, to a pressure of at least 40 bar, particularly at least 50 bar, particularly at least 60 bar, preferably up to a maximum of 180 bar. It is particularly preferred if the scroll compressor is configured to compress the high-pressure refrigerant to a pressure between 60 bar and 180 bar, particularly between 90 bar and 150 bar, preferably to 120 bar.

[0027] A subordinate aspect of the invention relates to a vehicle air conditioning system, in particular a vehicle air conditioning system with CO2 as a refrigerant, wherein the vehicle air conditioning system has a scroll compressor as previously described.

[0028] The invention is explained in more detail below with reference to the accompanying schematic drawings. These show:

[0029] Fig. 1 shows a cross-sectional view of a scroll compressor according to the invention in a preferred embodiment;

[0030] Fig. 2 shows a cross-sectional view of a scroll compressor according to a further preferred embodiment according to the invention; Fig. 3 shows a cross-sectional view of a scroll compressor according to a further preferred embodiment; and

[0031] Fig. 4A - 4C Detailed views of different variants of axial sliding bearings for a scroll compressor according to the invention in preferred embodiments.

[0032] Figures 1-3 each show a cross-sectional view of a scroll compressor according to the invention, which has a drive chamber 10 and a compression chamber 20. The drive chamber 10 and the compression chamber 20 are bounded by a housing 14. The housing 14 can be made up of multiple parts and, in particular, may have a central housing body and a cover closing it. The housing 14 is preferably gas-tight.

[0033] The separation between the drive chamber 10 and the compression chamber 20 is achieved by a housing partition 15. The housing partition 15 can, in particular, be arranged in a main housing part 14a, which is axially closed by a housing cover 14b. The housing cover 14b forms an outer boundary of the compression chamber 20.

[0034] A drive 11, preferably an electric motor, is arranged in the drive chamber 10. The drive 11 drives a drive shaft 12, which extends through the housing partition 15 into the compression chamber 20. The drive shaft 12 is appropriately sealed against the housing partition 15 and supported in a rolling bearing 13, which is fixed in the housing partition 15.

[0035] The drive shaft 12 has an eccentric pin that engages with an orbiting displacement spiral 21. The orbiting displacement spiral 21 is arranged in the compression chamber 20 together with a counter-spiral 22. The displacement spiral 21 comprises one or more spiral walls that engage with the counter-spiral 22. The counter-spiral 22 has corresponding, counter-rotating spiral walls. Thus, the displacement spiral 21 and the counter-spiral 22 are arranged in an interlocking manner. The counter-spiral 22 is rigidly connected to the housing 14. The counter-spiral 22 preferably does not move during operation of the scroll compressor. The displacement spiral 21 is set into an orbiting motion by the eccentric pin 19.To ensure that the displacement spiral 21 does not rotate in a circular path, an anti-rotation mechanism 50 is provided, which in the embodiments shown here is designed as a pin-ring system. For this purpose, several cylindrical blind bores or blind openings are provided in the displacement spiral 21, opening towards the drive chamber 10. Pins, fixed in a central plate 16, engage in these blind openings. The central plate 16 is located between the displacement spiral 21 and the housing intermediate wall 15. To ensure smooth sliding of the pins along the inner walls of the blind bores, the inner walls of the blind bores are preferably equipped with a ring element 28. The ring element 28 is preferably frictionally and / or positively locked in the blind bore of the displacement spiral 21.

[0036] Between the displacement spiral 21 and the counter-spiral 22, one or more compression chambers 30 are formed. The compression chambers are bounded by the respective bottoms of the displacement spiral 21 and the counter-spiral 22, as well as by the spiral walls of the displacement spiral 21 and the counter-spiral 22. The compression chambers 30 are variable, meaning their volume changes during operation of the scroll compressor. This volume change is used to compress a refrigerant.

[0037] The refrigerant is typically introduced into the compression chambers 30 from a radially outer edge region of the compression chamber 20. The refrigerant is compressed by the orbiting motion of the displacement spiral 21 between the spiral walls of the displacement spiral 21 and the counter-spiral 22, and simultaneously conveyed towards the center of the counter-spiral 22. Maximum compression is reached at the center of the counter-spiral 22, and the compressed refrigerant can escape through an outlet opening 25 into a high-pressure region 29. The high-pressure region 29 can be formed in the housing cover 14b. From the high-pressure region 29, the compressed refrigerant can then exit the scroll compressor.

[0038] In the embodiments shown in Figures 1-3, the displacer spiral 21 and the counter-spiral 22 each have an axial gap. This means that the spiral walls of the displacer spiral 21 do not directly and immediately abut the base of the counter-spiral 22. Conversely, the spiral walls of the counter-spiral 22 do not directly abut the base of the displacer spiral 21. To prevent refrigerant from escaping the compression chambers 30 through this axial gap, a peak seal 23, 24 is provided. The displacer spiral 21 has a first peak seal element 23, and the counter-spiral 22 has a second peak seal element 24. The tip seals 23, 24 each bridge the axial gap between the displacer spiral 21 and the counter spiral 22 and thus seal the two spirals well against each other.

[0039] The scroll compressor according to the invention is particularly intended for use in the compression of high-pressure refrigerants, especially CO2. With such refrigerants, very high pressures, which can reach up to 180 bar, are generated in the compression chamber 30. The pressure of the refrigerant acts on the displacer spiral 21 and the counter spiral 22 such that the displacer spiral 21 and the counter spiral 22 are forced apart. To prevent the displacer spiral 21 from lifting away from the counter spiral 22 under this pressure, thereby reducing or eliminating the sealing effect of the tip seal 23, 24, the displacer spiral 21 is supported by the axial sliding bearing 17.

[0040] The pressure generated in the compression chamber 30 between the displacer spiral 21 and the counter spiral 22 results in a compressor force F acting in the axial direction. v, which presses the displacer spiral 21 against the housing partition 15, specifically the intermediate plate 16. Although the intermediate plate 16 preferably has a smooth surface to facilitate the sliding of the displacer spiral 21 in its orbiting movement on the intermediate plate 16, the axial sliding bearing 17 arranged between the displacer spiral 21 and the housing partition 15, in particular the intermediate plate 16, is subjected to a high frictional force when the displacer spiral 21 moves, which would lead to high wear.

[0041] To reduce this wear, the embodiments of the scroll compressor according to the invention provide a pressure chamber 40 between the displacement spiral 21 and the housing partition 15, which is at least temporarily fluidly connected to or fluidly connected with the compression chamber 30. Through this fluid connection, refrigerant, which has been compressed to a high pressure by the displacement spiral 21, is directed into the pressure chamber 40, so that the pressurized refrigerant presses against the back of the displacement spiral 21. The fluid pressure prevailing in the pressure chamber 40 thus generates an axial counterforce F. G , which acts on the displacement spiral 21 and relieves it. The frictional force acting on the axial sliding bearing 17 is thus reduced, thereby decreasing the wear of the axial sliding bearing 17.

[0042] In Fig. 1, the forces acting in opposite directions on the displacement spiral 21 are shown, namely the compressor force F.v and the opposing force FG, represented by corresponding arrows. It is also evident that the relationship between the compressor force F v and the opposing force F G is set so that the forces do not completely cancel each other out, but rather the compressor force Fv generally predominates. However, it is preferable if the difference between the compressor force F v and the opposing force F G is as low as possible in order to reduce the friction on the axial sliding bearing 17 to a minimum.

[0043] The embodiments of the scroll compressor according to the invention shown in Figs. 1-3 essentially have the aforementioned design features and differ only in the way in which the fluid connection between the compression chamber 30 and the pressure chamber 40 is achieved.

[0044] In the embodiment shown in Fig. 1, a single through-channel 33 is arranged in the displacement spiral 21, which connects the compression chamber 30 to the pressure chamber 40, at least temporarily, i.e., during specific time intervals while the displacement spiral 21 is moving. Additionally, in the embodiment shown in Fig. 1, a return channel 34 runs from the high-pressure area 29 through a throttle 35 into the pressure chamber 40. The return channel 34 extends through the housing 14 and the housing partition 15. The pressure chamber 40 is pressurized essentially continuously via the return channel 34. This base pressure is subject to only minor fluctuations and is, in a broad sense, constant. The base pressure preferably lies between the suction and high pressure.

[0045] A substantially constant base pressure can be set in the pressure chamber 40 via the return channel 34. The peak pressure exceeding the base pressure is reduced in the pressure chamber 40 by the through-channel 33 establishing a direct connection between the compression chamber 30 and the pressure chamber 40 at predetermined positions during the orbiting movement of the displacement spiral 21. Fig. 2 shows another variant, which essentially corresponds to the variant according to Fig. 1, except that the return channel 34 is omitted. In the embodiment according to Fig. 2, only the single through-channel 33 is responsible for the fluid connection between the compression chamber 30 and the pressure chamber 40.The through-channel 33 is preferably positioned such that, in the activated state of the scroll compressor, the through-channel establishes a fluid connection with the pressure chamber 40 when between 70% and 100%, particularly between 90% and 100%, and particularly 95%, of the relative compression chamber volume is reached. Specifically, the through-channel 33 can be positioned such that, outside the aforementioned value ranges, it is generally covered by a spiral wall of the counter-spiral 22, so that no fluid connection exists. However, as soon as 75% to 100%, particularly 95%, of the relative compression chamber volume is reached, the fluid connection to the pressure chamber 40 is established by opening the through-channel 33. Preferably, the through-channel 33 then remains open while the displacement spiral 21 performs a rotation through an angle of 120° to 360°, particularly 270°.

[0046] Only then does the through channel 33 close again or is covered by the counter spiral 22.

[0047] In the variant according to Fig. 3, unlike the scroll compressors described above, there is not a single through-channel 33 in the displacement spiral 21, but rather two through-channels 31, 32 in the displacement spiral.

[0048] The displacement spiral 21 is arranged in a first through-channel 31 located near the center of the displacement spiral 21. A second through-channel 32 is arranged in a radially outer section of the displacement spiral 21. The radial outer region of the displacement spiral 21 is also referred to as the initial region, since the compression of the refrigerant begins here. The central region of the displacement spiral 21 essentially corresponds to a middle region in which the refrigerant has the highest pressure.

[0049] An advantageous aspect of the scroll compressor according to the invention is the reduction of wear in the area of ​​the axial sliding bearing 17. Several forces act on the axial sliding bearing 17. On the one hand, the compressor force Fv acts on the axial sliding bearing 17, which results from the force in the compressor chamber 30 between the displacement spiral 21 and the counter spiral.

[0050] The refrigerant pressure generated by the compressor is 22. In addition, a rotating tilting moment acts on the displacement spiral 21, which places an additional load on the axial sliding bearing 17. To maintain the stability of the axial sliding bearing 17, different axial sliding bearing configurations are provided. In all configurations, however, the pressure setting in the pressure chamber 40 is a crucial factor. By adjusting the pressure in the pressure chamber 40 so that the counterforce FG equals the compressor force F vas long as the value does not exceed the limit, it is ensured that the displacement spiral 21 continuously rests against the intermediate wall 15 of the housing or the intermediate plate 16 and is thus well guided.

[0051] Figure 4a shows one way to position the axial sliding bearing 17 between the displacer spiral 21 and the center plate 16. To ensure that the axial sliding bearing 17 follows the orbiting motion of the displacer spiral 21, it is particularly advantageous to position the axial sliding bearing 17 in a bearing groove 26. The bearing groove 26 is bounded on a radial inner and a radial outer side by a radial flange 27. The axial sliding bearing 17 is inserted into the bearing groove 26 and secured laterally by the radial flanges 27. It is specifically designed that the axial sliding bearing 17 projects beyond the radial flanges 27 to ensure that essentially only the axial sliding bearing 17 is in contact with the center plate 16.The central plate 16 and the axial sliding bearing 17 are preferably made of materials that slide well against each other, for example plastics, so that low friction is achieved while ensuring sufficient sealing.

[0052] Fig. 4b shows an alternative variant of the arrangement of the axial sliding bearing 17.

[0053] In this variant, the displacement spiral 21 has only a radially outer flange 27, which radially delimits the axial sliding bearing 17. On an inner side, the axial sliding bearing 17 projects with an overhang 18 into a blind opening in the displacement spiral 21. The blind opening is part of the anti-rotation mechanism 50. A ring element 28 is arranged in the blind opening. The axial sliding bearing 17, with its overhang 18, projects beyond the edge of the blind opening and essentially covers an axial portion of the ring element 28. In this way, the overhang 18 essentially forms an axial retainer or an axial positive locking mechanism for the ring element 28. Simultaneously, in the variant according to Fig. 4b, the axial sliding bearing 17 has an increased width. In this way, the sliding contact surface between the

[0054] The axial sliding bearing 17 and the center plate 16 are increased. This helps the axial sliding bearing 17 to absorb not only the contact pressure of the displacement spiral 21, but also, in particular, tilting moments.

[0055] The variant shown in Fig. 4c provides that the displacement spiral 21 has a radial flange 21 only on one inner side, in particular on a side facing a blind hole of the anti-rotation mechanism 50. The radial flange 21 prevents radial slippage of the axial sliding bearing 17. On a radially outer side of the displacement spiral 21, the axial sliding bearing 17 projects beyond the outer circumferential surface of the displacement spiral 21 with an overhang 18. The overhang 18 is designed to have a length less than half the length of the axial sliding bearing 17 in order to prevent tilting of the axial sliding bearing 17. In the variant shown in Fig. 4c, the focus is particularly on compensating tilting moments. The arrangement of the axial sliding bearing 17 in a radially outer area of ​​the displacement spiral 21, in particular in the maximally radial outer area of ​​the displacement spiral 21, ensures good support of the displacement spiral 21 against tilting moments.Furthermore, the overhang 18 can serve to support the displacement spiral 21 against the counter spiral 22 in a radial direction.

[0056] In general, all embodiments may include an additional compensation mechanism for the scroll compressor, located in the region of the eccentric pin 19, which reduces vibrations in the scroll compressor that may arise due to gas forces and manufacturing tolerances. Such a compensation mechanism, also called a swing link, is described by way of example in WO 2022 / 033 934 A1, to which full reference is hereby made.

[0057] The scroll compressor described here is particularly suitable as a compression machine for a vehicle air conditioning system that uses CO2 as a refrigerant. Especially with regard to electromobility, it is preferably provided that the drive 11 of the scroll compressor is formed by an electric motor. The drive 11 is preferably also arranged in the housing 14, in particular in the main housing part 14a, of the scroll compressor. Reference numeral list

[0058] 10 Engine room

[0059] 11 Drive

[0060] 12 Drive shaft

[0061] 13 rolling bearings

[0062] 14 cases

[0063] 14a Main housing part

[0064] 14b Housing cover

[0065] 15 Housing partition

[0066] 16 Middle plate

[0067] 17 axial plain bearings

[0068] 18 Overhang

[0069] 19 eccentric pins

[0070] 20 Congestion area

[0071] 21 Displacement spiral

[0072] 22 Counter-spiral

[0073] 23 first top seal

[0074] 24 second peak seal

[0075] 25 Outlet opening

[0076] 26 bearing groove

[0077] 27 Radial flange

[0078] 28 ring element

[0079] 29 High-pressure area

[0080] 30 compression chamber

[0081] 31 first through channel

[0082] 32 second through channel

[0083] 33 Through channel

[0084] 34 Feedback channel

[0085] 35 Throttle

[0086] 40 Pressure chamber 50 Anti-rotation mechanism

Claims

Patent claims 1. Scroll compressor for compressing high-pressure refrigerant, particularly for automotive applications, comprising a drive chamber (10) in which a drive (11) is arranged, and a compression chamber (20) separated from the drive chamber (10) by a housing partition (15), in which an orbiting displacer spiral (21) is arranged, which engages with a counter-spiral (22) such that at least one variable compression chamber (30) for compressing the high-pressure refrigerant is formed between the displacer spiral (21) and the counter-spiral (22), wherein an axial gap is formed between the displacer spiral (21) and the counter-spiral (22), which is sealed by a tip seal (23, 24), characterized in that a pressure chamber (40) is formed between the displacer spiral (21) and the housing partition (15), which at least temporarily is fluidly connectable or fluidly connected to the compression chamber (30).

2. Scroll compressor according to claim 1 characterized in that the displacement spiral (21 ) has at least one through-channel (31 , 32, 33) which establishes a fluid connection between the compression chamber (30) and the pressure chamber (40), so that the pressure chamber (40) can be supplied with high-pressure refrigerant from the compression chamber (30).

3. Scroll compressor according to claim 2 characterized in that the through-channel (31 , 32, 33) is formed in such a section of the displacement spiral (21 ) in which the through-channel (31 , 32, 33) is open in the activated state of the scroll compressor when reaching 70% - 100%, in particular 90% - 100%, in particular 95%, of the relative compression chamber volume and remains open during a rotation of the displacement spiral (21 ) by a rotation angle of 120° - 360°, in particular 255° - 315°, in particular 270°, following the opening.

4. Scroll compressor according to claim 2 or 3 characterized in that the through-channel (31 , 32, 33) in the displacement spiral (21) is arranged such that during operation, the through-channel (31 , 32, 33) is temporarily arranged at least section by section in a first compression chamber and subsequently temporarily arranged at least section by section in a second compression chamber due to the orbiting movement of the displacement spiral (21).

5. Scroll compressor according to one of the preceding claims characterized in that the displacement spiral (21 ) has a first through-channel (31) and a second through-channel (32), wherein the first through-channel (31) is formed substantially in a middle section and the second through-channel (32) is formed in an initial region of the displacement spiral (21 ).

6. Scroll compressor according to one of the preceding claims characterized in that the displacement spiral (21 ) slides over a central plate (16) which is arranged between the housing intermediate wall (15) and the displacement spiral (21), wherein an axial sliding bearing (17) is arranged between the central plate (16) and the displacement spiral (21).

7. Scroll compressor according to claim 6 characterized in that an anti-rotation mechanism (50) is arranged between the middle plate (16) and the displacement spiral (21).

8. Scroll compressor according to one of the preceding claims characterized in that the tip seal (23, 24) comprises or consists of a plastic material, in particular polytetrafluoroethylene, polyphenylene sulfide or polyetheretherketone, preferably each enriched by fillers.

9. Scroll compressor according to one of the preceding claims characterized in that the tip seal (23, 24) has a thickness between 1 mm and 3 mm, in particular 2 mm.

10. Scroll compressor according to one of claims 6 to 9 characterized in that the axial sliding bearing (17) comprises or consists of a plastic material, in particular polytetrafluoroethylene, polyphenylene sulfide, polyetheretherketone, polyetherketone, polyaryletherketone, preferably each enriched by fillers.

11. Scroll compressor according to one of claims 6 to 10 characterized in that the axial sliding bearing (17) has a rectangular cross-section with an aspect ratio between 0.2 and 0.

6.

12. Scroll compressor according to one of the preceding claims characterized in that the scroll compressor is configured to compress high-pressure refrigerant to a pressure of at least 40 bar, in particular at least 50 bar, in particular at least 60 bar, preferably up to a maximum of 180 bar.

13. Vehicle air conditioning system, in particular vehicle air conditioning system with CO2 as refrigerant, with a scroll compressor according to one of the preceding claims.

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