Compressor with water-lubricated sliding bearing

Abstract

The invention relates to a compressor (20) for generating a compressed air flow for a fuel cell (10), the compressor having a compressor element (21), in particular a compressor wheel, wherein the compressor element (21) is coupled in a rotationally fixed manner to a drive shaft (23), wherein the drive shaft (23) is driven by a motor (22), in particular an electric motor, wherein the shaft (23) is rotatably supported by means of at least one hydrodynamic or hydrostatic sliding bearing (24, 25), wherein the sliding bearing (24, 25) is connected to a lubricant supply (30) via which the sliding bearing (24, 25) is supplied with lubricant in order to generate a hydrodynamic or hydrostatic pressure, wherein the lubricant is water or a fluid mixture having predominantly water, wherein the sliding bearing (24, 25) has a lubricant inlet and a lubricant outlet, wherein lubricant can be introduced into the sliding bearing (24, 25) via the lubricant inlet and can be conducted away from the sliding bearing (24, 25) via the lubricant outlet, and wherein a conducting-away region of the circulation system (30) is arranged in the region of the lubricant outlet. If the entire outlet cross section of the liquid outlet of the sliding bearing (24, 25) is completely covered by the lubricant held in the conducting-away region, then a reliable constructional approach for such a compressor can be achieved.

Description

TECHNICAL FIELD

[0001] The invention relates to a compressor for generating a compressed air flow for a fuel cell, the compressor having a compressor element, in particular a compressor wheel, wherein the compressor element is coupled in a rotationally fixed manner to a drive shaft, wherein the drive shaft is driven by a motor, in particular an electric motor, wherein the shaft is rotatably supported by means of at least one hydrodynamic or hydrostatic sliding bearing, wherein the sliding bearing is connected to a lubricant supply, via which the sliding bearing is supplied with lubricant in order to generate a hydrodynamic or hydrostatic pressure, wherein the lubricant is water or a fluid mixture having predominantly water, wherein the sliding bearing has a lubricant inlet and a lubricant outlet, wherein lubricant can be introduced into the sliding bearing via the lubricant inlet and can be conducted away from the sliding bearing via the lubricant outlet, and wherein a conducting-away region of a circulation system is arranged in the region of the lubricant outlet. BACKGROUND

[0002] Fuel cells which are operated with pure hydrogen are nowadays considered as future drives, since they emit only pure water vapor. Hydrogen and air are fed to the fuel cell in the reaction chamber. It has been found that the power density and the efficiency of the fuel cell increase when air which is under pressure is fed. In order to provide compressed air a loading unit is required. For this purpose, an electric compressor or a turbo compressor is usually used. In the electric compressor the compressor element is driven by an electric motor. In the present invention the compressor element is in particular understood to be a compressor wheel or a screw compressor. In the present invention the compressor wheel can in particular be a compressor wheel which sucks in air along its axis of rotation and subsequently blows away compressed compressed air in the radial direction. Such a compressor wheel is also usually referred to as a radial ventilator.

[0003] In order to support the shaft which carries the compressor element, different bearing types are used in the prior art. Bearings with rolling elements or sliding bearings are known. In this case sliding bearings are considered on the basis of mainly high rotational speeds. The hydrodynamic sliding bearings which are used here require a lubricant which is introduced in the hydrodynamic gap between the rotor and the stator of the sliding bearing. Usually oil is used as lubricant. In the case of the use of oil there is the risk that oil enters the air circuit by leakage and is fed to the fuel cell. The contamination of the membranes of the fuel cell by oil leads to their destruction.

[0004] Therefore, solutions are known from the prior art in which water is used as lubricant. Thus, EP 2 600 015 A1 describes a turbo compressor for a fuel cell system, wherein the drive shaft of the compressor is supported on a sliding bearing which is lubricated with water.

[0005] A similar solution is disclosed in DE 10 2009 051 560 Al. In this document it is also described that the water mixture can be added with additives, for example antifreeze. The term water is therefore also understood in the present application as an aqueous solution in which the water is added with one or more additives, in particular antifreeze. The additives can also here be used without damaging effect on the membrane of the fuel cell.

[0006] It has been found that bearing failure occurs when using water, in particular in high-speed rotating compressor elements. SUMMARY

[0007] It is therefore the object of the present application to provide a compressor of the type mentioned at the outset, by means of which a reliable mode of operation is achieved in the case of the use of water as lubricant in the sliding bearing.

[0008] According to the application this object is achieved by the fact that the entire outlet cross-section of the liquid outlet of one sliding bearing or of the liquid outlets of a plurality of sliding bearings is completely covered with lubricant in the discharge region.

[0009] The inventors have found that the technical solution known from the prior art, which immediately adjoins the lubricant outlet of the sliding bearing, can lead to the formation of foam in the lubricant in certain operating situations. The simultaneously occurring gas bubbles are guided together in the lubricant circuit and are then again delivered to the sliding bearing. Due to the insufficient lubricating ability of the air, the load capacity of the sliding bearing then decreases. As a result, the bearing surfaces can be damaged (bearing erosion). The inventors have surprisingly found that the formation of foam can be significantly reduced or prevented if the entire outlet cross-section of the liquid outlet of the sliding bearing is completely covered with lubricant. In this way, bearing damage is effectively prevented.

[0010] According to a particularly preferred variant of the application it can be provided that the circulation system is completely filled with lubricant and is vented. In this way it is ensured that no air accumulates in the region of the lubricant supply, which air is unintentionally guided together and transported to the sliding bearing.

[0011] If it is provided here that the circulation system has a venting connection to a venting line, the system can be simply filled and maintained at this time.

[0012] According to the application it can be particularly preferably provided that the lubricant supply forms a closed circulation system. The closed system ensures a continuous lubricant supply. In particular, the unintentional entry of substances into the lubricant supply is prevented, which substances can cause damage to the membrane of the fuel cell.

[0013] It is particularly preferred that the lubricant is held under pressure such that the lubricant pressure in the region of the outlet cross section of the at least one sliding bearing is greater than the ambient pressure and the lubricant pressure in the region of the outlet cross section is preferably at least 0.5 bar and more preferably at most 5 bar. It has been found that the formation of foam immediately adjacent to the sliding bearing can additionally be effectively suppressed in the case of a correspondingly applied lubricant pressure. As a result of this measure, virtually no further damaging bubble formation occurs. The operating safety is thereby further improved. A closed lubricant circulation system is preferably used. This has already been mentioned above. In the case of the use of such a closed lubricant circulation system, it is proposed that the entire circulation system is under pressure, wherein the aforementioned pressure information can be taken into account.

[0014] A variant of the application which can be envisaged is that an exhaust device is provided, the lubricant which is led out of the lubricant outlet of the sliding bearing is fed to the exhaust device and the gas which is transported in the lubricant is at least partially separated from the lubricant in the exhaust device. By means of this measure, the gas content in the lubricant is further reduced. Common release methods can be used here. The gas which is carried in the lubricant can be separated at low pressure, for example in a region in the circulation system.

[0015] It has been found that a bubble-free lubricant supply is achieved by arranging the at least one sliding bearing in a bearing housing and feeding the lubricant to the sliding bearing by means of a lubricant input line of the lubricant supply which is below the sliding bearing in the direction of gravity.

[0016] Additionally or alternatively, it can be provided for this purpose that the at least one sliding bearing is arranged in a bearing housing, the lubricant is led away via a lubricant discharge line and the lubricant discharge line leads the lubricant away from the sliding bearing above the sliding bearing in the direction of gravity.

[0017] It is also conceivable in the present application that a lubricant pump is provided, which feeds the lubricant to the at least one sliding bearing and which is preferably arranged below the sliding bearing in the geodetic height.

[0018] A preferred refinement according to the application can be provided in that a heat exchanger is arranged before the at least one sliding bearing in the flow direction, through which the lubricant is guided in order to draw off heat therefrom. In this way, the sliding bearing can also be cooled efficiently at the same time by means of the lubricant.

[0019] If the compressor element and the drive shaft and the motor, in particular an electric motor, are arranged in the compressor housing in such a way that the lubricant supply forms a closed circulation system with a lubricant pump and the circulation system is configured in or on the compressor housing, the compressor can be operated simply. In the simplest case, for example, the design can be carried out in such a way that, in order to be connected to a fuel cell system, only the air guide is coupled, the compressor element being arranged in the air guide.

[0020] A turbocompressor can also be used in the application, wherein a turbine is configured on the shaft carrying the compressor wheel. The exhaust gas stream from the fuel cell can be fed to the turbine. The power consumption of the electric motor can thereby be reduced. If this construction is used, the turbine can be supported in the compressor housing, for example. The air guide of the turbine can then also be connected to the fuel cell.

[0021] In a preferred refinement of the application, the motor for driving the compressor element, which is configured as an electric motor, can be connected to a power electronics device, wherein the power electronics device is preferably fixed in or on the compressor housing, wherein a heat exchanger is assigned to the power electronics device, which is in heat-exchanging contact with the heat- generating regions of the power electronics device, and the lubricant is fed as a coolant to one or more sliding bearings after the heat exchanger in the flow direction. The component costs of the compressor can thereby be further reduced.

[0022] According to the application, the motor for driving the compressor element, which is configured as an electric motor, can also be assigned a heat exchanger, and the lubricant fed to or output from one or more sliding bearings is guided as a coolant through the heat exchanger. The electric motor is thereby cooled directly by the lubricant.

[0023] The bearing for the shaft of the compressor element can be formed by a hydrodynamic sliding bearing. In particular, one or more sliding bearings are configured as hydrodynamic sliding bearings, wherein the hydrodynamic sliding bearing has a rotor and a stator, wherein the rotor is rotatable relative to the stator, wherein a rotor bearing surface and a counter surface of the stator are arranged opposite one another to generate a hydrodynamic pressure in the region of a converging gap, such that the rotor bearing surface and / or the counter surface form a continuous bearing profile in a sectional view along and through the rotational axis, which is preferably formed by at least two profile sections, which are particularly preferably configured as straight lines and cambered portions or as a plurality of cambered portions, in order to generate hydrodynamic load-bearing properties in the radial and axial directions, wherein it is preferably provided that the bearing profile is always differentiable along the rotational axis in a sectional view along and through the rotational axis.

[0024] With the aid of this support a particularly high load capacity is achieved in a minimum of structural space. In particular, varying axial and radial loads occurring during operation can be reliably eliminated.

[0025] Here a multi-sided plain bearing is particularly effective, with the aid of which the instability of the lubricating film and vibrations caused by unbalance can be effectively suppressed. To this end it is also possible for the rotor bearing surface and the counter surface of one plain bearing or of a plurality of plain bearings to form a multi-sided plain bearing.

[0026] In the arrangement according to the application the plain bearing is lubricated with a water-based lubricant. In order to use the compressor for operating a fuel cell it is important for the support to be sealed with respect to the gas flow path. If, for example, an antifreeze agent, for example ethylene glycol, is contained in the water, this reduces the power performance of the fuel cell although the antifreeze agent does not destroy the membrane. It is thereby possible for the compressor element to be held in the region of an air guide which has an air delivery and, downstream of the compressor element, a pressure line via which the compressed air generated by the compressor element can be conducted away, so that the shaft is led out of the bearing housing in which one plain bearing or a plurality of plain bearings are arranged and into the region of the air guide and the shaft lead-through into the region of the air guide from the bearing housing is sealed with the aid of a combination of a slip ring seal and a gas-powered seal. An effective sealing is thereby also achieved in the case of a lubricant which is conducted under overpressure with respect to the environment in a lubricant circuit. It is also conceivable for the sealing effect to be achieved via sealing air which is intercepted at the compressor outlet. BRIEF DESCRIPTION OF DRAWINGS

[0027] The application is described in detail below on the basis of the embodiments shown in the drawings. There are shown:

[0028] Figure 1 and Figure 2 schematically a fuel cell system with a compressor,

[0029] Figures 3 to 7 schematically a compressor for use in a fuel cell system according to Figure 1 . DETAILED DESCRIPTION

[0030] Figure 1 A schematic representation of a fuel cell 10 with a reaction chamber 13 is shown. In the reaction chamber 13 a membrane 14 is provided which separates the anode chamber and the cathode chamber from one another. An anode 15 is held in the anode chamber and a cathode 16 is held in the cathode chamber. Hydrogen can be fed to the anode chamber via an input line 12 from a hydrogen reservoir 11.

[0031] From the compressor 20 compressed air can be fed to the cathode chamber. An exhaust line 17 leads out of the reaction chamber 13. The exhaust gas produced during the chemical reaction in the fuel cell 10 can be removed via the exhaust line 17 in the form of water vapor.

[0032] In the exhaust line 17 a water separator 18 can be integrated. The water separator 18 has a water outlet 18.1. Via the water outlet separated water can be removed. The water separator 18 also has a gas line 18.2. Via the gas line the gaseous phase separated in the water separator 18 can be removed.

[0033] The anode 15 and the cathode 16 are connected to a transformer 40. Via the transformer 40 a battery 43 can be connected by means of a cable 42. Thus during operation the battery 43 can be charged by the fuel cell 10. In addition to the transformer 40 a converter 50 can also be connected via a cable 44. In the converter 50 the direct current produced by the fuel cell 10 or output by the battery 43 is converted into alternating current. The alternating current is conducted via a cable 51 to an electric motor 60. The electric motor 60 can for example be a drive unit of a motor vehicle.

[0034] The compressor 20 has a compressor housing 27. In the compressor housing 27 a bearing housing (not shown) is arranged. The bearing housing has two sliding bearings 24, 25 which are arranged spaced apart from one another. The sliding bearings are preferably configured as hydrodynamic sliding bearings 24, 25. By means of the sliding bearings 24, 25 the drive shaft 23 is rotatably supported in the bearing housing. On the drive shaft 23 a motor 22, i.e. an electric motor, is connected.

[0035] The motor 22 drives the drive shaft 23. The compressor element 21 is also connected to the drive shaft 23 in a rotationally fixed manner. The compressor element 21 is a compressor wheel, preferably a radial fan. The radial fan sucks in ambient air along its axis of rotation. The sucked-in air is compressed in the compressor wheel and blown out radially. The compressed compressed air is fed via a pressure line 21.2 to the cathode 16 of the fuel cell 10. Ambient air is fed via the air feed 21.2.

[0036] The motor 22 is fed via an electrical power source. For this purpose in this embodiment the battery 43 is used as the electrical power source. The electric motor 22 is connected to a power electronics 26 which controls the function of the electric motor 22. The power electronics 26 is preferably mounted on or in the compressor housing 27. From the power electronics 26 a current line 26.1 leads to the transformer 14 (cable 41).

[0037] Figure 2 A compressor design is shown which essentially corresponds to the design of the compressor according to Figure 1 In order to avoid repetitions, reference is therefore made to the preceding embodiments. In the following only the differences are described in detail.

[0038] As Figure 2 shown, the gas line 18.2 is introduced into the compressor housing 27 and is fed to the turbine 28 there. In the turbine 28 the reaction gas under pressure and from the fuel cell 10 can be discharged. The discharged gas is discharged via the gas guide 18.5 and is led away from the compressor housing 27.

[0039] The turbine 28 is connected to the drive shaft 23 and is connected therewith in a rotationally fixed manner. In this way the mechanical drive power generated in the turbine 28 can be transmitted to the drive shaft 23. The electric motor 22 is thereby unloaded and its power consumption is thereby reduced.

[0040] The turbine 28 can be assigned a bypass line 18.3. The bypass line 18.3 connects the gas line 18.2 with the gas guide 18.5, bypassing the turbine 28. In the bypass line 18.3 a valve 18.4 is integrated. The valve 18.4 can be opened or closed depending on the pressure situation. The turbine 28 is thereby either bypassed or completely or partially flowed through by the reaction gas.

[0041] Figures 3 to 7 Variants of the compressor 20 are shown. In these schematic drawings the turbine 28 (and the gas line 18.2, the gas guide 18.5 and the bypass 18.3) is shown in a dashed line schematic. The dashed line schematic is symbolic, two alternative designs of the compressor 20 are possible, one with the turbine 28 and one without the turbine 28.

[0042] According to Figures 3 to 7 the design is in principle referred to the variant of the compressor 20 according to Figure 1 and Figure 2 To avoid repetitions reference is made to the preceding embodiments. Only the changes shown in the figures are explained.

[0043] Figure 3 It is shown that a lubricant supply 30 is assigned to the two plain bearings 24, 25. Via the lubricant supply 30 the two plain bearings 24, 25 can be supplied with the required lubricant.

[0044] In the present application water or a water mixture is used as lubricant, to which water additives, for example antifreeze, can be added, the use of other additives is also conceivable.

[0045] The lubricant supply 30 has a lubricant input line 31, which is introduced into the compressor housing 27. In the compressor housing 27 the lubricant input line 31 is connected to a lubricant pump 33. The lubricant pump 33 pumps lubricant into a pump line 34. From the pump line 34 branch lines 35, 36 lead, which lead to the plain bearings 24, 25, respectively.

[0046] As Figure 3 It can be seen that the lubricant pump 33 is arranged in geodetic height below the two plain bearings 24, 25 when the compressor 20 is installed as intended.

[0047] During operation of the compressor 20, the drive shaft 23 rotates and the compressor element 21 rotates therewith. Lubricant is fed to the plain bearings 24, 25 in the region of the lubricant inlet of the plain bearings. Due to the rotation of the drive shaft 23, the lubricant is fed through the converging gap of the hydrodynamic plain bearings 24, 25. The lubricant leaves the hydrodynamic plain bearings 24, 25 in the region of the lubricant outlet of the plain bearings. The lubricant outlet opens into a collection region, in which the lubricant remains. The lubricant covers the entire cross section of the lubricant outlet in the collection region. Thereby, the formation of foam in the lubricant is reduced or suppressed. Furthermore, the collection region can be under overpressure relative to the environment. Thereby, the suppression of the formation of foam is further promoted.

[0048] Directly adjacent to the collection region of the two plain bearings 24, 25, the lubricant flows into a collector 29. A lubricant discharge line 32 is connected to the collector 29. The lubricant discharge line 32 leads out of the compressor housing 27.

[0049] As Figure 3 It can be seen that the lubricant discharge line 32 is preferably arranged in geodetic height above the two plain bearings 24, 25 in the intended installed state of the compressor. In other words, the lubricant discharge line is arranged above the plain bearings 24, 25 in the direction of gravity. This additionally promotes the evacuation of the lubricant. For the residual gaseous substances present in the lubricant, it is possible here to at least partially separate them out.

[0050] Figure 4 An improved design according to the design of the application according to Figure 3 is shown. As shown in the schematic diagram, a heat exchanger 70 is assigned to the power electronics 26 for operating the motor 22. The heat exchanger 70 can be placed directly onto the power electronics 26, wherein, for example, ribbed heat exchanger fins are provided in the heat exchanger, which are connected to the heat-generating faces of the power electronics 26. The heat exchanger fins are then swept around by the flowing lubricant, so that heat can be transferred into the lubricant here.

[0051] It is also conceivable that, for example, cooling plates are provided in the heat exchanger 70, which are connected to the power electronics, for example by means of a paste having a high thermal conductivity. The heat exchanger can conduct the lubricant via the cooling plates.

[0052] The heat exchanger 70 can be integrated into the lubricant supply 30. For example, the heat exchanger can be arranged as Figure 4It is connected to and can be flowed through the pump line 34, so as to exchange the heat lost by the power electronics 26 into the lubricant.

[0053] Pump line 34 is connected to heat exchanger 70, such as in Figure 3 It is connected to two hydrodynamic sliding bearings 24 and 25.

[0054] Figure 5 It shows according to Figure 4 An improved design scheme is proposed. Here is an example of... Figure 4 A heat exchanger 70 is allocated to the power electronics 26. However, the heat exchanger is now integrated into the lubricant discharge line 32 and connected to the collector 29 via line section 32.1.

[0055] Similarly, as in Figure 4 Zhongyouxuan is also Figure 5 In the compressor housing 27, the heat exchanger 70 and power electronics 26 are arranged within the compressor housing 27. However, it is also conceivable to arrange one or two such units outside the compressor housing 27.

[0056] exist Figure 4 Due to the heat from the power electronics 26, the lubricant is heated before entering the sliding bearings 24 and 25.

[0057] exist Figure 5 The lubricant from the sliding bearings 24 and 25 is supplied to the heat exchanger 70. If the heat exchanger 70 is arranged downstream of the sliding bearings 24 and 25, it has the advantage that the sliding bearings 24 and 25 can be lubricated by means of a liquid with similar temperature control in all operating conditions.

[0058] Figure 6 It shows the relationship with Figure 4 A similar design for compressor 20 is used. As shown in the schematic diagram, the lubricant supply mechanism 30 preferably has a closed circulation system. The circulation system 30 is completely filled with lubricant and is vented.

[0059] Therefore, the lubricant discharge line is connected to line 38.1. This line can, for example, lead to heat exchanger 39. However, heat exchanger 39 can also be integrated into the circulation system at any different location.

[0060] Pipeline 39.1 leads from heat exchanger 39 back to lubricant pump 33. Heat exchanger 39 is used to transfer heat from the lubricant to the environment. This reduces the temperature level of the lubricant.

[0061] Preferably, such as Figure 6 The entire circulation system is arranged within the compressor housing 27. This forms a closed system that does not require connection to the environment, thus enabling simple installation and operation.

[0062] Figure 6 A compensation vessel 38 for compensating the common structure integrated in the circulation system is also shown. By means of the compensation vessel 38, the temperature-dependent thermal expansion of the lubricant can be compensated.

[0063] If a closed lubricant circuit is provided, as shown in Figure 6 , which is arranged in or on the compressor housing 27, it is only necessary to couple the pressure line 21.2 to the fuel cell 10 in order to connect to the fuel cell 10. Then only the air delivery 21.2 has to be additionally guided via the area boundary of the compressor 20 (dashed representation of the compressor housing 27).

[0064] If the compressor variant is provided with a turbine 28, the gas line 18.2 and the gas guide 18.5 also have to be guided via the area boundary.

[0065] However, as shown in Figure 7 , the circulation system 30 does not have to be completely present in or on the compressor housing 27. It is also conceivable that only a part of the circulation system 30 is guided in or on the compressor housing 27.

[0066] It is especially conceivable that the circulation system 30 is connected to an external heat exchanger 39. The heat exchanger 39 can for example also be part of the cooling system of a motor vehicle.

Claims

1. A compressor (20) for generating a compressed air flow for a fuel cell (10), the compressor having a compressor element (21) wherein the compressor element (21) is non-rotatably coupled to a drive shaft (23), wherein the drive shaft (23) is driven by a motor (22), wherein the shaft (23) is rotatably supported by at least one hydrodynamic or hydrostatic sliding bearing (24, 25), wherein the sliding bearing (24, 25) is connected to a lubricant supply mechanism, via which lubricant is supplied to the sliding bearing (24, 25) to generate hydrodynamic or hydrostatic pressure, wherein the lubricant is water or a fluid mixture mainly containing water, wherein the sliding bearing (24, 25) has a lubricant inlet and a lubricant outlet, wherein lubricant can be introduced into the sliding bearing (24, 25) via the lubricant inlet and can be withdrawn from the sliding bearing (24, 25) via the lubricant outlet, and wherein a guide area of ​​a circulation system is provided in the region of the lubricant outlet, characterized in that, The entire outlet cross-section of the liquid outlet of the sliding bearing (24, 25) is completely covered by the lubricant retained in the guide area.

2. The compressor (20) according to claim 1, characterized in that, The lubricant supply mechanism is completely filled with lubricant and then vented.

3. The compressor (20) according to claim 2, characterized in that, The circulation system has an exhaust port that connects to the exhaust pipe.

4. The compressor (20) according to any one of claims 1 to 3, characterized in that, The lubricant supply mechanism forms a closed circulation system.

5. The compressor (20) according to any one of claims 1 to 3, characterized in that, The lubricant is kept under pressure such that the lubricant pressure in the region of the outlet cross-section of the liquid outlet of the sliding bearing (24, 25) is greater than the ambient pressure.

6. The compressor (20) according to claim 5, characterized in that, The lubricant pressure in the region of the outlet cross section is at least 0.5 bar.

7. The compressor (20) according to claim 6, characterized in that, The lubricant pressure in the region of the outlet cross section is at least 5 bar.

8. The compressor (20) according to any one of claims 1 to 3, characterized in that, An exhaust device is provided to supply lubricant drawn from the lubricant outlet of the sliding bearings (24, 25) to the exhaust device, and in the exhaust device, at least partially separates the gas transported in the lubricant from the lubricant.

9. The compressor (20) according to any one of claims 1 to 3, characterized in that, At least one sliding bearing (24, 25) is arranged in the bearing housing, and the lubricant inlet line (31) of the lubricant supply mechanism delivers lubricant to the sliding bearing (24, 25) below the sliding bearing (24, 25) in the direction of gravity.

10. The compressor (20) according to any one of claims 1 to 3, characterized in that, At least one sliding bearing (24, 25) is arranged in a bearing housing, and lubricant is carried away via a lubricant discharge line (32), and the lubricant discharge line (32) carries the lubricant away from the sliding bearing (24, 25) above the sliding bearing (24, 25) in the direction of gravity.

11. The compressor (20) according to any one of claims 1 to 3, characterized in that, A lubricant pump (33) is provided to deliver lubricant to at least one sliding bearing (24, 25), and the lubricant pump (33) is arranged at a geodetic height below the sliding bearing (24, 25).

12. The compressor (20) according to any one of claims 1 to 3, characterized in that, The at least one sliding bearing (24, 25) is fluidly connected to the heat exchanger (39) to absorb heat from the lubricant.

13. The compressor (20) according to any one of claims 1 to 3, characterized in that, The compressor element (21), the drive shaft (23), and the motor (22) are arranged in the compressor housing (27) such that the lubricant supply mechanism forms a closed-loop system with a lubricant pump (33), and the loop system is constructed in or on the compressor housing (27).

14. The compressor (20) according to any one of claims 1 to 3, characterized in that, A motor (22) configured as an electric motor for driving the compressor element (21) is connected to a power electronics device (26), wherein a heat exchanger (70) is provided for the power electronics device (26), the heat exchanger being in heat-exchange contact with the heat-generating area of ​​the power electronics device (26), and the lubricant is delivered as a coolant to one or more of the sliding bearings (24, 25) in the flow direction after the heat exchanger (70).

15. The compressor (20) according to claim 14, characterized in that, The power electronics (26) is fixed on or inside the compressor housing (27).

16. The compressor (20) according to any one of claims 1 to 3, characterized in that, A heat exchanger (70) is provided for the motor (22) configured as an electric motor to drive the compressor element (21), and the lubricant supplied to or output from one or more of the sliding bearings (24, 25) is guided as a coolant through the heat exchanger (70).

17. The compressor (20) according to any one of claims 1 to 3, characterized in that, One or more of the said sliding bearings (24, 25) are configured as hydrodynamic sliding bearings (24, 25), wherein the one or more said hydrodynamic sliding bearings (24, 25) have a rotor and a stator, wherein the rotor is rotatable relative to the stator, wherein the rotor support surface is opposed to the mating surface of the stator to generate hydrodynamic pressure in the region of the converging gap, such that the rotor support surface and / or the mating surface form a continuous bearing profile in a cross-section along and through the axis of rotation in a sectional view, the bearing profile being formed by at least two profile segments configured as straight lines and arches or configured as multiple arches to generate hydrodynamic load-bearing capacity in the radial and axial directions.

18. The compressor (20) according to claim 17, characterized in that, This ensures that, in a cross-section along and through the axis of rotation in a sectional view, the bearing profile is always differentiable along the axis of rotation.

19. The compressor (20) according to claim 17 or 18, characterized in that, The rotor support surface (13) and mating surface (21) of one or more of the sliding bearings (24, 25) form a multi-faceted sliding bearing.

20. The compressor (20) according to any one of claims 1 to 3, characterized in that, The compressor element (21) is held in the region of the air guide, which has an air delivery section (21.1) and a pressure line (21.2) downstream of the compressor element (21) through which compressed air generated by the compressor element (21) can be guided, such that the shaft (23) is led out from the bearing housing in which one or more of the sliding bearings (24, 25) are arranged and introduced into the region of the air guide, and the shaft penetration portion from the bearing housing into the region of the air guide is sealed by means of a combination of a slip ring seal and a pneumatic seal.

21. The compressor (20) according to any one of claims 1 to 3, characterized in that, The compressor component mentioned above is a compressor wheel.

22. The compressor (20) according to claim 1 or 13, characterized in that, The motor mentioned is an electric motor.

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