Gas compressor with pressure relief for one compressor wheel

Abstract

Gas compressor comprising a compressor housing (10) with a compressor chamber (11), a gas inlet (12) and a gas outlet (13), a compressor wheel (1) rotatably arranged in the compressor chamber (11) about an axis of rotation (R) to convey a gas from the gas inlet (12) to the gas outlet (13), a rear wall (15) axially facing a rear side of the compressor wheel (1) and axially delimiting the compressor chamber (11), a drive shaft (2) for the compressor wheel (1), a bearing housing (20) non-rotatably joined to the compressor housing (10) and / or the rear wall (15) for supporting the drive shaft (2), wherein the bearing housing (20) comprises a main structure (21) and an auxiliary structure (22) arranged axially between the rear wall (15) and the main structure (21), and a venting system with a distribution chamber (19) for leakage gas, which is separated from an end face of the rear wall (15) and is bounded on an axially opposite end face by the additional structure (22).

Description

[0001] The invention relates to a gas compressor with a compressor wheel for conveying a gas. More specifically, the invention relates to relieving axial pressure on the compressor wheel by discharging leakage gas that reaches the rear of the compressor wheel during conveyance. The gas to be conveyed can be air, in particular fresh air, or pure oxygen or oxygen-enriched air, or in principle also another gas. The gas compressor can be used, for example, to supply a fuel cell or a fuel cell system with a reaction gas, such as reaction air.

[0002] In radial-flow gas compressors, as the invention particularly relates to, pressurized gas reaches the rear of the compressor wheel via sealing gaps between the compressor wheel and a compressor housing. This leakage gas generates an axial force on the rear of the compressor wheel, corresponding to the frontal contact surface, which must be absorbed in an axial bearing of a rotary bearing for the compressor wheel and / or a drive shaft. To reduce the rear pressure and thus the axial force, the leakage gas is discharged from the rear of the compressor wheel via vent lines, which involves design effort and cannot always be optimally solved. The provision of the axial bearing, which is usually designed as a gas foil bearing, also creates complexity in the design and assembly of the compressors.

[0003] In a gas compressor known from EP 4 067 669 A1, the leakage gas is guided into a bearing chamber via a rear wall of the compressor housing, axially opposite the compressor wheel at the rear, and is then removed from the bearing chamber via vent lines, for example, returned to a gas inlet of the compressor housing. An axial gas foil bearing is formed in the bearing chamber. The bearing chamber is defined on one end by a bearing housing, which rotatably supports the drive shaft, and on the other end by the rear wall of the compressor housing. One bearing foil is arranged on the bearing housing and another bearing foil on the rear wall.

[0004] EP 2 772 652 A2 discloses a gas compressor in which the leakage gas is discharged via aligned bores in the rear wall of the compressor housing and the axially adjoining bearing housing.

[0005] It is an object of the invention to provide a gas compressor with improved pressure relief of the compressor wheel.

[0006] It is desirable to increase the flexibility in the design of a ventilation system for pressure relief of the compressor wheel.

[0007] Another or further task can be seen in facilitating the assembly of the gas compressor.

[0008] A gas compressor, as per the invention, comprises a compressor wheel and a compressor housing with a compressor chamber, a gas inlet, and a gas outlet. The compressor wheel is arranged in the compressor chamber so as to be rotatable about a rotational axis in order to convey a gas from the gas inlet to the gas outlet. A rear wall defines the compressor chamber on a rear side of the compressor wheel facing away from the gas inlet. The rear wall can be considered part of the compressor housing. The gas compressor further comprises a drive shaft for the compressor wheel and a bearing housing for the rotational mounting of the drive shaft and / or the compressor wheel. The bearing housing is joined to the compressor housing and / or the rear wall in a rotationally fixed manner.

[0009] The compressor wheel can be connected to the drive shaft in a rotationally immovable manner. Advantageously, it is arranged coaxially to the drive shaft. In principle, the drive shaft can only be coupled to the compressor wheel via one or more intermediate links for torque transmission. Preferably, however, the compressor wheel and the drive shaft are directly coupled. In particular, they can be coupled to one another in a shaft-socket engagement and in this configuration, preferably directly and non-rotatably in the manner of a sliding joint. They can also be connected in an axially immovable manner, for example, forming a press fit. For a rotationally immovable coupling, a pin can protrude axially from the rear of the compressor wheel and into a cavity in the drive shaft. Alternatively, the drive shaft can protrude into the compressor wheel and / or through the compressor wheel.If the drive shaft extends through the compressor wheel, the compressor wheel can be mounted on the drive shaft in a rotationally fixed manner and connected to it axially. Alternatively, a connecting piece can protrude from the rear of the compressor wheel, into which the drive shaft extends axially. In principle, other types of direct rotary coupling are also conceivable. In preferred embodiments, the drive shaft and the compressor wheel form a fixed rotary connection with respect to rotational movements about the rotational axis, with a direct positive and / or frictional coupling being preferred. Preferably, they are also axially immovably coupled relative to one another.

[0010] The bearing housing can form or accommodate a radial bearing and / or an axial bearing for the rotary support of the drive shaft and / or the compressor wheel.

[0011] The drive shaft can extend through the bearing housing and into the rear wall of the compressor housing, or it can also extend through the rear wall. Alternatively or additionally, a journal or stud of the compressor wheel can extend through the rear wall of the compressor housing and, in advantageous designs, further axially until it overlaps with the bearing housing. The drive shaft and the journal or stud of the compressor wheel can interlock in the area of ​​the bearing housing for a rotationally fixed coupling.

[0012] According to the invention, the bearing housing comprises a main structure and an additional structure arranged axially between the rear wall and the main structure. The additional structure is formed separately from the compressor housing, the rear wall, and in particular separately from the main structure. It is joined to the main structure and / or the rear wall and / or the compressor housing in a rotationally immobile manner. Preferably, the additional structure is joined at least to the main structure. A detachable joint, for example, a screw connection, is advantageous.

[0013] The main structure and the additional structure can be joined directly to one another, so that they can be joined to the compressor housing and / or the rear wall as a pre-joined unit, i.e., as an assembled bearing housing. The additional structure can be joined directly to the main structure only and then connected to the compressor housing and / or the rear wall via the main structure. Alternatively, the assembled bearing housing can also be joined to the compressor housing and / or the rear wall in the area of ​​the main structure and the additional structure, or only in the area of ​​the additional structure.

[0014] In a first aspect, the invention relates to the pressure relief of the compressor wheel and for this purpose comprises a venting system with a distribution chamber which is delimited on one of its two end faces by the rear wall and on the other axially opposite end face by the additional structure. The rear wall can advantageously delimit the distribution chamber on one end face, circumferentially running around the axis of rotation over the entire radial extent of the distribution chamber and thus already at the end face alone. Alternatively, the distribution chamber can be delimited jointly at the end face in question by the rear wall and another wall structure, for example the compressor housing. The additional structure can delimit the distribution chamber on the other end face, circumferentially running around the axis of rotation over its entire radial extent and thus already at the end face alone.Alternatively, the distribution chamber can be defined jointly at the relevant end face by the additional structure and, for example, the main structure.

[0015] The venting system comprises one or more first vent lines extending in the region of the rear wall and opening into the distribution chamber, through which leakage gas can be discharged from the rear of the compressor wheel into the distribution chamber. Furthermore, the venting system comprises one or more second vent lines, which also open into the distribution chamber or each open into the distribution chamber, to discharge the leakage gas from the distribution chamber.

[0016] The one or more first vent lines can be provided on an outer periphery of the rear wall and / or an inner periphery of the rear wall. In advantageous embodiments, the one or more first vent lines extend through the rear wall, for example, each in the form of a straight passage, such as a bore. The respective passage is advantageously an axial passage, but can also be inclined relative to the rotation axis.

[0017] The one or more second vent lines can be provided in the region of the additional structure, for example, on an outer periphery of the additional structure and / or an inner periphery of the additional structure. In advantageous embodiments, the one or more second vent lines extend through the additional structure, for example, each in the form of a straight passage, such as a bore. The respective passage is advantageously an axial passage, but can also be inclined relative to the axis of rotation.

[0018] The distribution chamber formed by the additional structure increases flexibility regarding the design and arrangement of the vent lines. For example, the one or more first vent lines that carry the leakage gas into the distribution chamber do not need to be aligned with the second vent line(s) leading thereto. With a sufficiently large radial extension of the distribution chamber, radially relative to the rotation axis, the freedom regarding the arrangement of the respective first vent line and respective second vent line can be further increased. The distribution chamber provides space for the arrangement and design of the vent lines.

[0019] The distribution chamber can thus extend radially outward farther than the compressor wheel. Preferably, the distribution chamber extends radially beyond the compressor wheel at all points around the rotational axis. It can extend radially as far as the gas outlet of the compressor housing and even further outward, overlapping the gas outlet, i.e., extending axially alongside the gas outlet. Radially inward, the distribution chamber can extend as far as the rotating component, i.e., as far as the drive shaft and / or the compressor wheel.

[0020] The leakage gas can be discharged from the rear of the compressor wheel via the distribution chamber with reduced flow resistance. The axial forces exerted by the leakage gas on the compressor wheel can be reduced accordingly. These axial forces are absorbed in an axial pivot bearing, referred to below as "axial bearing", for the compressor wheel and / or the drive shaft. Due to the associated reduction in the axial bearing gap, they cause the bearing components of the axial bearing to heat up. This heating can lead to bearing damage and / or limit the speed and / or gas throughput of the compressor. A more effective reduction of the axial forces thus prevents premature bearing damage and / or enables operation at increased speed and / or increased gas throughput and / or a downsizing of the compressor by increasing the speed at a given throughput.

[0021] In the design of the distribution chamber, the rear wall and the additional structure around the distribution chamber can be axially adjacent to one another and delimit the distribution chamber across its outer circumference. The additional structure can form the entire frontal boundary of the distribution chamber on the bearing housing side. Alternatively, the rear wall and the main structure around the distribution chamber can be axially adjacent to one another and delimit the distribution chamber across their outer circumference. In such designs, they can surround the additional structure so that on the bearing housing side, the additional structure forms only a partial area of ​​the frontal boundary of the distribution chamber and the main structure forms another partial area of ​​the frontal boundary.

[0022] The rear wall and / or the additional structure can each be, in particular, plate-like or disc-like or disc-shaped. The rear wall and / or the additional structure can delimit the distribution chamber at the respective end face with an at least substantially planar end surface. The distribution chamber can be obtained at least substantially by an axial recess in the rear wall and / or an axial recess in the additional structure, wherein the respective recess can advantageously extend over at least the majority of the end face of the rear wall and / or the additional structure.

[0023] According to a second aspect, the main structure and the additional structure delimit a bearing chamber in which an axial bearing for the drive shaft is formed. For its axial support, the gas compressor comprises a shaft bearing structure that is axially immovably and preferably also rotationally immovably connected to the drive shaft, which protrudes radially outward into the bearing chamber thus formed and is axially supported in the bearing chamber on at least one of its two end faces on the axial bearing. The shaft bearing structure can be axially immovably and optionally rotationally immovably connected to the drive shaft directly or via one or more intermediate members, for example the compressor wheel and / or a positioning sleeve. In this case, an axial bearing can be formed on an end face of the main structure axially facing the shaft bearing structure or on an end face of the additional structure axially facing the other end face of the shaft bearing structure.In advantageous embodiments, the shaft bearing structure is supported on both end faces in the bearing chamber by means of a thrust bearing. One thrust bearing can be located on a face of the main structure axially facing the shaft bearing structure, and the other thrust bearing can be located on a face of the additional structure axially facing the other face of the shaft bearing structure. The axial forces acting on the compressor wheel are absorbed by the shaft bearing structure in the thrust bearing.

[0024] In advantageous embodiments, the axial bearing is a gas foil bearing and comprises a bearing foil that is arranged in the bearing space on an end face of the additional structure facing the shaft bearing structure, so as to be rotationally immovable relative to the latter, or on an end face of the main structure facing the shaft bearing structure, so as to be rotationally immovable relative to the latter, in order to form an axial bearing gap with the shaft bearing structure at the respective end face. Preferably, one bearing foil is arranged on an end face of the additional structure facing the shaft bearing structure, so as to be rotationally immovable relative to the latter, and another bearing foil is arranged on an end face of the main structure facing the shaft bearing structure, so as to be rotationally immovable relative to the latter, so that a gas foil bearing is formed on both end faces of the shaft bearing structure.

[0025] If the gas compressor comprises both the storage chamber and the distribution chamber, the distribution chamber can advantageously be fluidically connected to the storage chamber in order to be able to discharge leakage gas from the distribution chamber into the storage chamber. Preferably, only the additional structure extends axially between the distribution chamber and the storage chamber, which then delimits the distribution chamber with one of its two end faces and the storage chamber with the other. The arrangement of the storage chamber axially next to the distribution chamber enables a short fluid connection. The one or more second vent lines can extend into the storage chamber so that leakage gas from the distribution chamber can be discharged into the storage chamber.The discharge of leakage gas from the distribution chamber into the storage space can be implemented in a simple manner in the area of ​​the additional structure, for example by means of one or more straight passages through the additional structure or one or more grooves on the outer and / or inner circumference of the additional structure.

[0026] The leakage gas can serve as a cooling medium for the axial bearing. The position of the respective second vent line, which connects the bearing chamber to the distribution chamber, can be selected according to the radial extent of the distribution chamber, independent of the position of the respective first vent line, which carries the leakage gas into the distribution chamber. This opens up scope for optimizing the cooling of the axial bearing.

[0027] In designs in which the gas compressor comprises the storage chamber and the distribution chamber, the distribution chamber can extend radially outward at least as far as the storage chamber, preferably further than the storage chamber. It is advantageous if the distribution chamber extends radially outward at least as far as the storage chamber, preferably further than the storage chamber, at all points surrounding the axis of rotation. Even in the case of an advantageously large extension in the radial direction, it is advantageous if the volume of the distribution chamber is smaller than the volume of the storage chamber.

[0028] An electric drive motor with a stator and a rotor can be provided to rotate the compressor wheel. In advantageous embodiments, the rotor is arranged coaxially to the drive shaft and connected to it in a rotationally fixed manner. The stator can be arranged in a motor compartment and connected to a motor housing surrounding the motor compartment in a rotationally fixed manner. In an advantageously integrated design of compressor and drive motor, the motor housing is joined to the bearing housing and / or the compressor housing in a rotationally fixed manner. The motor housing can be pot-shaped and open in the axial direction towards the compressor wheel. The bearing housing can close the motor compartment at one end, except for a passage required for coupling the drive shaft and compressor wheel.

[0029] Instead of an electric drive motor, or preferably in addition to the electric drive motor, an expander wheel of an expander can be provided for the rotary drive of the compressor wheel, thus combining the gas compressor with an expander. In advantageous embodiments, the expander wheel is arranged coaxially to the drive shaft and connected to it in a rotationally fixed manner. If the electric drive motor and the expander wheel are present, their torques can be superimposed on the preferably shared drive shaft. Instead of an expander, the compressor and the electric drive motor can also be combined with a further, second gas compressor in the shared module housing, wherein the compressor wheel of the second gas compressor is preferably also coupled to the rotor of the electric drive motor in a rotationally fixed manner and can also be arranged coaxially with the rotor of the electric drive motor.The second compressor can advantageously be another gas compressor according to the invention. The two compressors can be arranged in parallel to increase the mass flow of the same gas. In alternative embodiments, they can be arranged in series, with one compressor downstream of the other, to form a second compressor stage.

[0030] If the distribution chamber is connected to the storage space for discharging the leakage gas, the gas compressor can have one or more further, third vent lines through which leakage gas can be discharged from the storage space. The one or more third vent lines advantageously extend in the region of the main structure. The one or more third vent lines can extend in particular through the main structure. Alternatively, they can extend over the outer circumference or the inner circumference of the main structure. One or more third vent lines can lead through the main structure and, at the same time, one or more further third vent lines can extend on the outer circumference and / or the inner circumference of the main structure. Particularly preferably, one or more third vent lines can each be provided as a straight passage in the main structure.The respective passage can be inclined to the rotation axis or, more advantageously, extend parallel to the rotation axis. The respective passage can, for example, be a through-hole. In designs with an integrated drive motor, the one or more third vent lines can connect the storage compartment with the engine compartment, for example.

[0031] In alternative embodiments, the leakage gas can be discharged from the distribution chamber, bypassing the storage chamber. Thus, one or more second vent lines can be connected to the compressor chamber upstream of the gas outlet, for example, upstream of the compressor wheel, so that leakage gas from the distribution chamber can be recirculated to the low-pressure region of the gas compressor.

[0032] In designs with an integrated drive motor, the one or more second vent lines can extend into the engine compartment, bypassing the bearing chamber, for example, in the area of ​​the bearing structure, in particular through the main structure. The engine compartment can be connected to the compressor chamber upstream of the gas outlet, for example, also upstream of the compressor wheel, so that leakage gas from the engine compartment can be recirculated to the low-pressure region of the gas compressor. In yet other designs, the leakage gas can be discharged from the distribution chamber into the low-pressure region of the compressor chamber, bypassing the bearing chamber and, in integrated designs, also bypassing the engine compartment.In this case, one or more second vent lines can extend, for example, through the additional structure and / or the main structure and / or through an axial joint gap formed by the main structure and the additional structure in axial contact with each other.

[0033] In further embodiments in which the gas compressor comprises the distribution chamber and the storage space, and the venting system for discharging the leakage gas from the distribution chamber comprises a plurality of second venting lines, one or more of the second venting lines can connect the distribution chamber to the storage space, while one or more other of the second venting lines bypasses the storage space. Thus, one or more other second venting lines can be connected to the compressor space upstream of the gas outlet, for example, also upstream of the compressor wheel, so that leakage gas from the distribution chamber can be recirculated to the low-pressure region of the gas compressor. In embodiments with an integrated drive motor, one or more other second venting lines can connect the distribution chamber directly to the engine compartment, bypassing the storage space.

[0034] The gas compressor can, for example, be a component of a turbocharger for a vehicle's internal combustion engine. In other applications, it can serve to supply a reaction system with a reaction gas. The reaction system can, in particular, be a fuel cell or an aggregation of several fuel cells for generating electrical energy, for example, for an electric drive motor of a vehicle. Accordingly, a fuel cell system with one or more fuel cells and the gas compressor, which is preferably combined with the electric drive motor and / or the expander in an integrated design to form a supply module, is a further subject of the invention.

[0035] Features of the invention are also described in the aspects formulated below. The aspects are formulated in the manner of claims and can replace them. Features disclosed in the aspects can further supplement and / or qualify the claims, show alternatives to individual features, and / or expand claim features. Reference numerals in parentheses refer to exemplary embodiments of the invention illustrated below in the figures. They do not limit the features described in the aspects in the literal sense as such, but on the other hand indicate preferred ways of implementing the respective feature.

[0036] Aspect 1# Gas compressors comprising: 1.1 a compressor housing (10) with a compressor chamber (11), a gas inlet (12) and a gas outlet (13), 1.2 a compressor wheel (1) which is arranged in the compressor chamber (11) so as to be rotatable about an axis of rotation (R) in order to convey a gas from the gas inlet (12) to the gas outlet (13), 1.3 a rear wall (15) which faces axially towards a rear side of the compressor wheel (1) and axially delimits the compressor chamber (11), 1.4 a drive shaft (2) for the compressor wheel (1), 1.5 optionally a shaft bearing structure (7) axially immovably connected to the drive shaft (2), and 1.6 a bearing housing (20) which is non-rotatably joined to the compressor housing (10) and / or the rear wall (15) for supporting the drive shaft (2), 1.7 wherein the bearing housing (20) comprises a main structure (21) and an additional structure (22) arranged axially between the rear wall (15) and the main structure (21), and 1.8 the additional structure (22) is formed separately from the compressor housing (10), the rear wall (15) and the main structure (21) and is joined in a rotationally immovable manner to at least one of the main structure (21), the compressor housing (10) and the rear wall (15).

[0037] Aspect 2# Gas compressor according to aspect 1, comprising: 2.1 a distribution chamber (19) which is bounded on one end face by the rear wall (15) and on an axially opposite end face by the additional structure (22), 2.2 a first vent line (16) extending in the region of the rear wall (15), preferably through the rear wall (15), and opening into the distribution chamber (19), through which leakage gas can be discharged from the rear side of the compressor wheel (1) into the distribution chamber (19), and 2.3 a second vent line (26; 26a; 26b), which also opens into the distribution chamber (19) in order to discharge the leakage gas from the distribution chamber (19).

[0038] Aspect 3# Gas compressor according to the preceding aspect, wherein the second vent line (26a; 26b) extends through the bearing housing (20) or at a periphery of the bearing housing (20), preferably through the main structure (21) or at a periphery of the main structure (21), into the distribution chamber (19) in order to discharge the leakage gas from the distribution chamber (19).

[0039] Aspect 4# Gas compressor according to one of the two immediately preceding aspects, wherein the second vent line (26) extends through the additional structure (22) or at a periphery of the additional structure (22) into the distribution chamber (19).

[0040] Aspect 5# Gas compressor according to one of the three immediately preceding aspects, comprising an electric drive motor (3) and a motor housing (30) which is connected to the bearing housing (20) and / or the compressor housing (10) in a rotationally immovable manner and surrounds a motor compartment (31) in which the drive motor (3) is arranged, wherein the distribution chamber (19) is connected directly or indirectly to the motor compartment (31) and / or the gas inlet (12) via the second vent line (26; 26a).

[0041] Aspect 6# Gas compressor according to one of the four immediately preceding aspects, wherein the distribution chamber (19) is connected to the gas inlet (12) via the second vent line (26; 26a; 26b), for example via the engine compartment (31) or bypassing the engine compartment (31) according to the preceding aspect.

[0042] Aspect 7# Gas compressor according to one of the preceding aspects, comprising the shaft bearing structure (7), wherein a bearing space (23) remains axially between the main structure (21) and the additional structure (22), into which bearing space the shaft bearing structure (7) projects radially outwards in order to form an axial bearing (7, 24, 25), preferably an axial gas foil bearing (7, 24, 25), for the drive shaft (2) in the bearing space (23).

[0043] Aspect 8# Gas compressor according to the preceding aspect, wherein the axial bearing (7, 24, 25) is a gas foil bearing and comprises a bearing foil (24) which is arranged in the bearing space (23) on an end face of the additional structure (22) facing the shaft bearing structure (7) in a rotationally immovable manner relative to the additional structure (22) and forms an axial bearing gap with the shaft bearing structure (7).

[0044] Aspect 9# Gas compressor according to one of the two immediately preceding aspects, wherein the axial bearing (7, 24, 25) is a gas foil bearing and comprises a bearing foil (25) which is arranged in the bearing space (23) on an end face of the main structure (21) facing the shaft bearing structure (7) in a rotationally immovable manner relative to the main structure (21) and forms an axial bearing gap with the shaft bearing structure (7).

[0045] Aspect 10# Gas compressor according to one of the three immediately preceding aspects, wherein the shaft bearing structure (7) is axially fixed relative to the drive shaft (2) on one end face by axial contact with an axial stop of the drive shaft (2) and on the other end face by axial contact with a nozzle (1a) projecting from the compressor wheel (1) or a positioning sleeve (1a) separate from the compressor wheel (1).

[0046] Aspect 11# Gas compressor according to one of the four immediately preceding aspects, wherein the storage space (23) is limited at the end faces and at the outer circumference only by the main structure (21) and the additional structure (22).

[0047] Aspect 12# Gas compressor according to one of the five immediately preceding aspects, each in combination with aspect 2, wherein the storage space (23) is fluidically connected to the distribution chamber (19) and thereby leakage gas can be discharged from the distribution chamber (19) into the storage space (23).

[0048] Aspect 13# Gas compressor according to one of the six immediately preceding aspects, each in combination with aspect 2, wherein the second vent line (26) extends into the storage space (23).

[0049] Aspect 14# Gas compressor according to one of the seven immediately preceding aspects, each in combination with aspect 2, wherein the second vent line (26) opens into the bearing chamber (23) radially peripherally of the axial bearing (7, 24, 25).

[0050] Aspect 15# Gas compressor according to one of aspects 7 to 12, each in combination with aspect 2, wherein the second vent line (26a; 26b) bypasses the storage space (23).

[0051] Aspect 16# Gas compressor according to aspect 2 in combination with one of aspects 7 to 14, comprising a third vent line (27) extending into the storage space (23), through which leakage gas can be discharged from the storage space (23).

[0052] Aspect 17# Gas compressor according to the preceding aspect, wherein the third vent line (27) extends into the storage space (23) through the storage structure (20) or at a periphery of the storage structure (20), preferably through the main structure (21) or at a periphery of the main structure (21).

[0053] Aspect 18# Gas compressor according to one of the two immediately preceding aspects, each in combination with aspect 5, wherein the distribution chamber (19) is connected to the engine compartment (31) via the third vent line (27).

[0054] Aspect 19# Gas compressor according to one of the three immediately preceding aspects, each in combination with aspect 5, wherein the third vent line (27) extends from the bearing space (23) into the engine space (31) through the bearing structure (20) or at a periphery of the bearing structure (20), preferably through the main structure (21) or at a periphery of the main structure (21).

[0055] Aspect 20# Gas compressor according to one of the four immediately preceding aspects, wherein the third vent line (27) opens into the bearing chamber (23) radially peripherally of the axial bearing (7, 24, 25).

[0056] Aspect 21# Gas compressor according to one of the preceding aspects in combination with aspect 2, wherein the distribution chamber (19) extends radially outwards further than the compressor wheel (1).

[0057] Aspect 22# Gas compressor according to one of the preceding aspects in combination with aspect 2, wherein the distribution chamber (19) extends radially into an overlap with the gas outlet (13).

[0058] Aspect 23# Gas compressor according to one of the preceding aspects in combination with aspect 2 and aspect 7, wherein the distribution chamber (19) extends radially outwards further than the storage space (23).

[0059] Aspect 24# Gas compressor according to one of the preceding aspects in combination with aspect 2 and aspect 7, wherein the volume of the distribution chamber (19) is smaller than the volume of the storage space (23).

[0060] Aspect 25# Gas compressor according to one of the preceding aspects, wherein the additional structure (22) is arranged on an end face of the main structure (21) axially facing the rear wall (15).

[0061] Aspect 26# Gas compressor according to one of the preceding aspects, wherein the additional structure (22) is plate-shaped or disc-shaped and bears against an end face of the main structure (21) axially facing the rear wall (15), and wherein the additional structure (22) is enclosed at an outer circumference, preferably by an inner circumference of the main structure (22).

[0062] Aspect 27# Gas compressor according to one of the preceding aspects, wherein the additional structure (22) is joined to the main structure (21), for example by means of a screw connection (24).

[0063] Aspect 28# Gas compressor according to one of the preceding aspects, wherein the main structure (21) and the additional structure (22) form the bearing housing (20) in the form of a pre-assembled assembly unit in which the shaft bearing structure (7) is rotatably received axially between the main structure (21) and the additional structure (22).

[0064] Aspect 29# Gas compressor according to one of the preceding aspects, wherein the compressor housing (10), the rear wall (15) and the compressor wheel (1) are components of a pre-assembled assembly unit and the compressor wheel (1) has an engagement member, for example an axle journal or a nozzle (1a) and the engagement member protrudes through the rear wall (15) for the rotationally immovable connection to the drive shaft (2).

[0065] Aspect 30# Gas compressor according to one of the preceding aspects, wherein the drive shaft (2) extends into or through the bearing housing (20).

[0066] Aspect 31# Gas compressor according to one of the preceding aspects, wherein the drive shaft (2) extends into or through the main structure (21) and optionally into or through the additional structure (22).

[0067] Aspect 32# Gas compressor according to one of the preceding aspects in combination with aspect 7, wherein the main structure (21) has an axial recess on an end face axially facing the rear wall (15) and the additional structure (22) delimits the recess on the end face, preferably terminates at the radially outer edge, and thereby forms the storage space (23) with the main structure (21).

[0068] Aspect 33# Gas compressor according to the preceding aspect, wherein the recess has a first axial section and a second axial section and widens radially from the first axial section in the direction of the rear wall (15) to form an annular shoulder surface into the second axial section, and wherein the additional structure (21) bears axially against the shoulder surface and axially closes off the recess.

[0069] Aspect 34# Gas compressor according to the preceding aspect, wherein the main structure (21) surrounds the additional structure (22) in the region of the second axial section, preferably enclosing it endlessly around the axis of rotation (R).

[0070] Aspect 35# Gas compressor according to one of the two immediately preceding aspects, wherein the recess widens radially from the second axial section in the direction of the rear wall (15) to form a further annular shoulder surface into a third axial section, and wherein the rear wall (15) bears axially against the further shoulder surface.

[0071] Aspect 36# Gas compressor according to one of the preceding aspects, wherein the rear wall (15) is clamped axially in the region of its outer circumference between the compressor housing (10) and the bearing housing (20), preferably between the compressor housing (10) on the one hand and the main structure (21) and / or the additional structure (22) on the other hand.

[0072] Aspect 37# Fuel cell system with a gas compressor according to one of the preceding aspects and a fuel cell which is connected to the gas outlet (13) so that the gas delivered by the gas compressor can be supplied to the fuel cell as reaction gas.

[0073] Aspect 38# Supply module comprising: 38.1 a gas compressor according to any one of the preceding aspects, 38.2 an electric drive motor (3) with a stator (4) and a rotor (5), and 38.3 a motor housing (30), wherein 38.4 the stator (4) is non-rotatably connected to the motor housing (30) and the rotor (5) is non-rotatably connected to the drive shaft (2), and 38.5 the compressor housing (10), the rear wall (15), the bearing housing (20) and the motor housing (30) are separately formed housing structures of a joined module housing.

[0074] Aspect 39# Supply module according to the preceding aspect, comprising an expander wheel (6) which is connected in a rotationally immovable manner to the drive shaft (2), and as a further component of the module housing an expander housing (40, 41) for the expander wheel (6).

[0075] Aspect 40# Supply module according to the preceding aspect, wherein the drive motor (3) is arranged axially between the compressor wheel (1) and the expander wheel (6).

[0076] Aspect 41# Gas compressor according to one of the two immediately preceding aspects, wherein the expander housing (40, 41) consists of one or more further separately formed housing structures and is joined to the motor housing (30).

[0077] Exemplary embodiments of the invention are explained below with reference to figures. Features revealed by the exemplary embodiments, individually and in any combination of features, advantageously develop the subject matter of the claims and aspects, as well as the embodiments described above. They show: Fig. 1 a supply module with a gas compressor of a first embodiment, Fig. 2 a partial area of ​​the supply module with a gas compressor of a second embodiment, Fig. 3 a partial area of ​​the supply module with a gas compressor of a third embodiment, and Fig. 4 an example of the use of the gas compressor.

[0078] Fig. 1 shows a gas compressor of a first exemplary embodiment. The gas compressor is a component of a modular supply unit, i.e., a supply module, for supplying a reaction system with a reaction gas. The reaction system can, in particular, be a fuel cell or an aggregation of several fuel cells for generating electrical energy for, for example, an electric drive motor of a vehicle. The supply module comprises the gas compressor with a compressor wheel 1, an electric drive motor 3, and an expander with an expander wheel 6, which are combined in a common, multi-part housing to form the supply module, which can be assembled as a single structural unit.The design of the supply module is such that the gas compressor can only function together with the drive motor 3, i.e., without the expander, and possibly also alone, without an integrated drive. In the latter case, it must be connected to another, external drive for the rotary drive. In preferred embodiments, however, the supply module is designed as a compact electrical charging system, as in the example.

[0079] The gas compressor comprises a compressor housing 10 and the compressor wheel 1, which is mounted in a compressor chamber 11 of the compressor housing 10 so as to be rotatable about a rotational axis R. When the compressor wheel 1 is driven in rotation, a gas G, which flows into the compressor chamber 11 at a gas inlet 12 of the compressor housing 10, is conveyed to a gas outlet 13 of the compressor housing 10 and discharged via the gas outlet 13 at increased pressure. The compressor wheel 1 is a radial compressor wheel, and the compressor housing 10 is accordingly designed as a spiral housing. The gas G flows axially toward the compressor wheel 1 and is deflected radially by the compressor wheel 1 toward the gas outlet 13. By the term “radial compressor wheel”, the invention also refers to a compressor wheel which is designed and arranged in such a way that the gas flows out at the periphery of the compressor wheel with a radial, a tangential and an axial directional component.The radial compressor wheel can, but does not have to, be designed and arranged in such a way that the gas flows only in the radial and tangential directions from the blades of the radial compressor wheel.

[0080] The compressor chamber 11 is defined by a rear wall 15 at the rear side of the compressor wheel 1, axially remote from the gas inlet 12, and is largely sealed. A sealing gap 14 remains between the compressor wheel 1 and the rear wall 15, circumferentially surrounding the rotational axis R, which is sealed in a suitable manner, for example, by means of a labyrinth seal.

[0081] For the rotary drive, the compressor wheel 1 is coupled to a drive shaft 2. The compressor wheel 1 and the drive shaft 2 are arranged coaxially and thus rotatable about the same axis of rotation R. The compressor wheel 1 is connected to the drive shaft 2 in a rotationally fixed manner. For example, a pin can protrude from the rear of the compressor wheel 1 and into the drive shaft 2, which in such designs is hollow at the end facing it. In the exemplary embodiment, however, the drive shaft 2 projects through the hollow compressor wheel 1. The compressor wheel 1 is secured against axial displacement on the drive shaft 1 and is rotationally fixedly coupled to the drive shaft 1 in direct engagement with the drive shaft 1. In principle, a direct or, if appropriate, an indirect coupling engagement between the compressor wheel 1 and the drive shaft 2 can also be designed differently, in which case the compressor wheel 1 and the drive shaft 2 are also preferably arranged coaxially.

[0082] The supply module comprises a bearing housing 20 for the rotary mounting of the drive shaft 2 and / or the compressor wheel 1 and a motor housing 30 for the electric drive motor 3, which is accommodated in a motor compartment 31 of the motor housing 30. The motor housing 30 delimits the motor compartment 31 over the circumference and at a rear side and is open at its front side facing the compressor wheel 1. The bearing housing 20 delimits the motor compartment 31 at the front of the motor housing 31. The drive motor 3 comprises a stator 4, which is connected in a rotationally fixed manner to the motor housing 30, and a rotor 5 that is rotationally fixed relative to the drive shaft 2. The drive motor 3 is designed as an internal rotor, and the rotor 5 is arranged directly on the outer circumference of the drive shaft 2. The rotor 5 consists essentially of permanent magnets, while the stator 4 comprises the electrical coils of the drive motor 3.

[0083] The expander comprises an expander housing 40 and the expander wheel 6, which is rotatably received in an expander chamber of the expander housing 40. The expander wheel 6 is of radial design. A propellant gas E flows radially against it via a gas inlet 42 and is rotationally driven by the propellant gas E. The propellant gas E is deflected when the expander wheel 6 is driven and flows out axially in a relaxed state via a gas outlet 43 of the expander housing 40. The expander wheel 6 is arranged coaxially to the drive shaft 2 and thus also coaxially to the compressor wheel 1 and can be rotationally immovably coupled to the drive shaft 2 in a rotational drive direction. The coupling can be designed as a direct engagement of the expander wheel 6 and the drive shaft 2 or as an indirect coupling, as explained above for the coupling of the compressor wheel 1 and the drive shaft 2.

[0084] The compressor wheel 1, the drive motor 3, and the expander wheel 6 are arranged axially next to one another, with the drive motor 3 in this arrangement between the compressor wheel 1 and the expander wheel 6. The compressor wheel 1 can be rotationally driven by the drive motor 3 or by the expander wheel 6, or simultaneously by the drive motor 3 and the expander wheel 6. An idle can be provided between the expander wheel 6 and the drive motor 3 so that the expander wheel 6 generates torque for the rotational drive of the compressor wheel 1 but is not dragged along by the drive motor 3.

[0085] Corresponding to the arrangement of compressor wheel 1, drive motor 3, and expander wheel 6, the multiple housing structures—namely, compressor housing 10, bearing housing 20, motor housing 30, and expander housing 40—are also arranged axially one after the other. In addition to these housing structures, the module housing comprises the aforementioned rear wall 15, which can be manufactured as a separate housing structure and arranged on the compressor housing 10, for example, pre-assembled, and an intermediate wall 41, which is arranged axially between the motor housing 30 and the expander housing 40. The rear wall 15 can be assigned to the compressor housing 10. The intermediate wall 41 can be assigned to the expander housing 40. It can be pre-assembled thereon or simply positioned and, in the pre-assembled or simply positioned state, joined to the motor housing 30 by means of a joining element 44. The compressor housing 1 is joined to the bearing housing 20 in a similar manner.

[0086] The bearing housing 20 comprises a main structure 21 and an additional structure 22. In the exemplary embodiment, it is composed of these two structures 21 and 22. The bearing housing 20 serves as the rotary bearing for the rotary assembly comprising the compressor wheel 1 and the drive shaft 2. Within the rotary bearing, this rotary assembly 1, 2 is supported in a radial bearing on the main structure 21. Furthermore, the rotary assembly 1, 2 is supported in an axial bearing of the bearing housing 20, in one axial direction on the main structure 21 and in the opposite axial direction on the additional structure 22. The additional structure 22 does not perform any function within the scope of the radial rotary bearing.

[0087] The axial bearing is formed in a bearing chamber 23, which is axially bounded on one axial end face by the main structure 21 and on the other opposite end face by the additional structure 22. A shaft bearing structure 7 projects radially outward from the rotary assembly 1, 2 into the bearing chamber 23. Fig. 1 it should be noted that the stationary components are shown in a longitudinal section and rotating components, such as the compressor wheel 1, the drive shaft 2, the expander wheel 6 and the shaft bearing structure 7, are shown in a side view.

[0088] The axial bearing is designed as a gas foil bearing. It comprises a bearing foil 24, which is arranged immovably on the additional structure 22, and a bearing foil 25, which is arranged immovably on the main structure 21. The shaft bearing structure 7 projects axially between the bearing foils 24 and 25 into the bearing space 23. The bearing foils 24 and 25 are each fixed immovably to the main structure 21 and the additional structure 22 by means of positioning elements 28. The positioning elements 28 are arranged peripherally of the shaft bearing structure 7 on the outer periphery of the bearing foils 24 and 25, distributed around the rotation axis R. The positioning elements 28 can, for example, be pin-shaped.

[0089] The additional structure 22 is arranged axially between the rear wall 15 and the main structure 21. It extends axially between the rear wall 15 and the storage space 23. It can advantageously be joined directly to the main structure 21, preferably detachably, as in the exemplary embodiment. In the exemplary embodiment, the main structure 21 and the additional structure 22 are joined directly to one another by means of a screw connection. For this purpose, the additional structure 22 has a plurality of axial passages, for example through-holes, distributed around the axis of rotation R, through which joining elements 29, for example screw elements, penetrate. The joining elements 29 project into corresponding receptacles in the main structure 21 and are fastened in the receptacles. The receptacles can each be provided with an internal thread in order to form a screw connection with the joining elements 29.

[0090] A distribution chamber 19 is formed axially between the rear wall 15 and the additional structure 22. The distribution chamber 19 is delimited on one of its two end faces by the rear wall 15 and on the other end face by the additional structure 22. The distribution chamber 19 is part of a venting system for relieving the pressure on the compressor wheel 1 and thereby reducing the axial force acting on the compressor wheel 1, which must be absorbed in the axial bearing. During compressor operation, leakage gas from the high-pressure region of the compressor housing 10 reaches the rear of the compressor wheel 1 via the sealing gap 14 formed between the compressor wheel 1 and the rear wall 15 and can subject it to an axial force acting in the direction of the gas inlet 12. In order to reduce the gas pressure at the rear of the compressor wheel 1, the leakage gas is discharged from the rear of the compressor wheel 1 in the region of the rear wall 15 into the distribution chamber 19.For dissipation, the rear wall 15 is provided with one or more first vent lines 16, which extend radially inward of the sealing gap 14 between the compressor wheel 1 and the rear wall 15 through the rear wall 15, for example, each as an axial, straight through-bore. The one or more first vent lines 16 are advantageously arranged radially further outward than an annular gap remaining between the rotating assembly 1, 2 and the rear wall 15. The vent system serves to reduce the axial forces to be absorbed in the axial bearing and thus to relieve the thermal load on the axial bearing.

[0091] The leakage gas flowing into the distribution chamber 19 during compressor operation is distributed within the distribution chamber 19 and can be discharged from the distribution chamber 19 at any location. For the discharge and thus removal of the leakage gas from the distribution chamber 19, the bearing housing 20 has one or more second vent lines 26.

[0092] In the first exemplary embodiment, the respective second vent line 26 extends through the additional structure 22. The respective vent line 26 can in particular be a straight, for example axial, passage through the additional structure 22. Expediently, the respective second vent line 26 is a simple axial or, if appropriate, inclined bore. In the exemplary embodiment, the respective second vent line 26 opens into the distribution chamber 19 and at the other end into the bearing chamber 23, thus connecting the distribution chamber 19 to the bearing chamber 23. As preferred, but only by way of example, the respective vent line 26 opens into the bearing chamber 23 peripherally of the shaft bearing structure 7 and also peripherally of the bearing foil 24. The space available for arranging the one or more second vent lines 26 increases or decreases depending on the extension of the distribution chamber 19 in the radial direction.Accordingly, constructive flexibility is created for the design of the ventilation system.

[0093] In order to be able to discharge the leakage gas from the distribution chamber 19, the ventilation system comprises one or more third ventilation lines 27 that connect the distribution chamber 19 to the engine compartment 31. The respective third ventilation line 27 opens peripherally from the shaft bearing structure 7 and also peripherally from the bearing foil 25 into the distribution chamber 19. The one or more second ventilation lines 26 and the one or more third ventilation lines 27 can open into the distribution chamber 19, in particular at the opposite end faces of the additional structure 22 and the main structure 21. They can, for example, open into the distribution chamber 19 radially at the same height and / or in pairs opposite one another. They can be aligned. The respective third ventilation line 27 can extend as a straight passage, in particular as an axial passage, for example as a through-bore, through the main structure 1.

[0094] The distribution chamber 19 not only provides flexibility for the design of the ventilation system, but also enables low-resistance discharge of the leakage gas, for example, to the low-pressure side of the compressor housing 10 and / or into the environment and / or into the motor compartment 31, where the leakage gas can serve to cool the drive motor 3. Furthermore, the division of the bearing housing 20 into a main structure 21 and an additional structure 22 facilitates the assembly of the axial bearing. The axial bearing, with its two bearing sides—namely, the main structure 21 with the bearing foil 25 on one end face and the additional structure 22 with the bearing foil 24 on the other end face of the shaft bearing structure 7—can be manufactured before the compressor housing 10 and bearing housing 20 are assembled. The bearing housing 20 can therefore be joined to the compressor housing 10 relatively easily with the axial bearing already pre-assembled.

[0095] During pre-assembly of the bearing housing 20, the main structure 21 can be pushed over the free front end of the drive shaft 2 onto the drive shaft 2 until it rests against an axial stop. The drive shaft 2 can form the axial stop. If the drive motor 3 is already arranged on the drive shaft 2, the stator 4 can form the axial stop instead. The bearing foil 25 can be arranged beforehand on the end face of the main structure 21 and pushed onto the drive shaft 2 together with it or only after the main structure 21 has been pushed onto it.

[0096] If the main structure 21 has one or more positioning elements 28, the bearing foil 25 is positioned rotationally immobile relative to the main structure 21 by means of the one or more positioning elements 28. The shaft bearing structure 7, if it is annular, can then be pushed over the free front end of the drive shaft 2 onto the drive shaft 2 in the direction of the bearing foil 25 until it touches an axial stop of the drive shaft 2. In a further step, the additional structure 22, with the bearing foil 24 first, is pushed onto the drive shaft 2 until it touches a front-end wing surface of the main structure 21 and joined to the main structure 21, for example by means of the joining elements 29. After this joining step, the shaft bearing structure 7 is received in the bearing space 23 thus formed between the bearing foils 24 and 25. Alternatively, the bearing foil 24 can also be pushed onto the drive shaft 2 before the additional structure 22 is pushed onto the drive shaft 2.If the additional structure 22 has one or more positioning elements 28, the bearing foil 24 is positioned on the end face of the additional structure 22 in a rotationally immovable manner relative to the latter by means of the one or more positioning elements 28. Alternatively, one or more positioning elements 28 provided on the main structure 21 can also serve to fix the bearing foil 24 in a rotationally immovable manner.

[0097] The pre-assembled unit, which comprises the bearing housing 20 with the shaft bearing structure 7 and the drive shaft 2, can be joined comparatively easily to the compressor housing 10, wherein the rotationally fixed coupling with the compressor wheel 1 is also produced in this further joining step.

[0098] After pre-assembly of the bearing housing 20, the rear wall 15 can be axially applied to the bearing housing 20, in the first embodiment to its additional structure 22, and the compressor wheel 1 can be pushed or slipped onto the drive shaft 2. A connecting piece 1a can protrude from the rear of the compressor wheel 1, which, in the fully assembled state, presses axially against the shaft bearing structure 7, so that the shaft bearing structure 7 is axially immovably fixed relative to the drive shaft 2 between the aforementioned axial stop of the drive shaft 2 and the connecting piece 1a of the compressor wheel 1. The compressor wheel 1 can then be secured to the drive shaft 2 with axial pressing force in order to form the rotary connection with the drive shaft 2. Finally, the compressor housing 10 is joined to the bearing housing 20.

[0099] The compressor wheel 1 can be connected to the drive shaft 2 in a rotationally fixed manner based solely on axial compression force. Additionally or instead, the rotationally fixed coupling can also be established by another frictional connection and / or by a positive engagement. The connecting piece 1a projecting rearward from the compressor wheel 1 can be replaced by a positioning sleeve or spacer sleeve separate from the compressor wheel 1, which can also form the aforementioned axial stop for the shaft bearing structure 7. In another modification, in a preceding step, the compressor wheel 1 can be placed in the compressor chamber 10 and the rear wall 15 can be fastened to the compressor housing 10.

[0100] The main structure 21 has a central passage for the drive shaft 2 and widens in several stages on its end face facing the compressor wheel 1. It has an inner first end face which extends radially outwards from the passage and axially delimits the bearing chamber 23 on one side. The bearing foil 25 is arranged on this end face in a rotationally immobile manner. An inner circumference which surrounds the bearing chamber 23 adjoins the inner end face radially on the outside. At the front end of the inner circumference, the main structure 21 widens radially outwards via a further end face. The additional structure 22 rests axially against this further end face, the aforementioned joining surface. The additional structure 22 has, at least essentially, the shape of a flat, round disk. It is tightly enclosed around its outer circumference by a further inner circumference of the main structure 21, running endlessly around its outer circumference.At the front end of this further inner circumference, the main structure 21 widens again to a front inner circumference. With this front inner circumference, the main structure 21 extends continuously around the rear wall 15 and tightly encloses it over its outer circumference. The compressor housing 10, in turn, continuously surrounds a front axial section of the main structure 21 and tightly encloses this front axial section of the main structure 21. A sealing ring is arranged in the annular gap between the compressor housing 10 and the main structure 21, sealing the annular gap.

[0101] The distribution chamber 19 extends radially beyond the compressor wheel 1 and in particular the one or more sealing gaps between the compressor wheel 1 and the rear wall 15 and advantageously radially up to the height of the gas outlet 13 and more preferably even up to an overlap with the gas outlet 13. The distribution chamber 21 is largely sealed at its periphery in a contact that rotates endlessly around the axis of rotation R directly between the rear wall 15 and the additional structure 22. The distribution chamber 19 extends radially inward up to a stub-shaped extension of the rear wall 15, which as a whole is essentially disk-shaped and points axially away from the compressor wheel 1. In principle, the distribution chamber 19 can also extend radially inward up to the drive shaft 2.

[0102] Fig. Figure 2 shows a partial section of a gas compressor of a second exemplary embodiment in longitudinal section. Visible are a portion of the compressor housing 10, the compressor wheel 1 arranged therein, a portion of the drive shaft 2, the bearing housing 20, and the drive motor 3, as well as a front portion of the motor compartment 31. The drive shaft 2 extends through the bearing housing 20, the rear wall 15, and also the compressor wheel 1. The compressor wheel 1 is non-rotatably connected to the drive shaft 2. The rotating assembly of the compressor wheel 1 and the drive shaft 2, including the shaft bearing structure 7, corresponds to the first exemplary embodiment. The compressor and the supply module as a whole differ from the first exemplary embodiment only with respect to the venting system.

[0103] As in the first embodiment, the rear wall 15 is provided with a plurality of first vent lines 16 radially inward of the sealing gap between the compressor wheel 1 and the rear wall 15. The vent lines 16 can be formed as straight, preferably axial passages, for example as through-bores.

[0104] In the second exemplary embodiment, the distribution chamber 19 is again delimited by the rear wall 15 on its front end facing the compressor wheel 1. On the rear end, it is delimited in a radially inner, central region by the additional structure 22 and in a radially outer, annular region by the main structure 21. The distribution chamber 19 thus extends radially beyond the additional structure 22. As in the first exemplary embodiment, the additional structure 22 lies axially directly against an end face of the main structure 21 and is endlessly enclosed on its outer circumference by the main structure 21. According to the first exemplary embodiment, the main structure 21 and the additional structure 22 form the bearing space 23 in which the rotating assembly comprising the compressor wheel 1 and the drive shaft 2 is supported axially on both sides by a bearing foil.

[0105] In contrast to the first exemplary embodiment, the leakage gas entering the distribution chamber 19 from the rear side of the compressor wheel 1 via the one or more first vent lines 16 is discharged from the distribution chamber 19 directly into the engine compartment 31, bypassing the bearing chamber 23. One or more second vent lines 26a extend through the main structure 21, bypassing the bearing chamber 23. The respective second vent line 26a can be formed, in particular, as a straight passage, preferably as an axial passage.

[0106] The leakage gas is discharged from the engine compartment 31 via one or more third vent lines 27a. The respective third vent line 27a extends through the main structure 21. In Fig. 2 shows a further vent line 17, which connects to the third vent line 27a or one of several third vent lines 27a. The further vent line 17 can be connected to the environment or, advantageously, to the low-pressure region of the compressor chamber 11 in order to return the leakage gas to the low-pressure region of the compressor chamber 11, for example, directly upstream of the compressor wheel 1 or closer to the gas inlet 12. The respective third vent line 27a can, for example, open into the respective further vent line 17 in a region that lies axially at the level of the distribution chamber 19 at a radial distance from the periphery of the distribution chamber 19. The respective third vent line 27a can, in particular, be formed as a straight passage, for example with an inclination to the axis of rotation R.

[0107] The leakage gas can optionally be additionally discharged from the distribution chamber 19 into the storage space 23. For this purpose, one or more second vent lines 26 can be provided in accordance with the first embodiment. Furthermore, one or more additional third vent lines can be provided to discharge leakage gas from the storage space 23. For example, several third vent lines 27 (cf. Fig. 1) as in the first embodiment, in addition to the one or more third vent lines 27a.

[0108] Apart from the differences explained above, the gas compressor of the second embodiment can be identical to that of the first embodiment. The same applies to the integrated supply module as a whole.

[0109] Fig. 3 shows a gas compressor of a third embodiment in the same sub-area as Fig. 2. The gas compressor of the third embodiment differs from the gas compressor of the second embodiment only with respect to the discharge of the leakage gas from the distribution chamber 19. The bearing housing 20 and the distribution chamber 19 correspond in their structure and shape to the second embodiment.

[0110] In the third embodiment, the leakage gas is discharged from the distribution chamber 19, bypassing the bearing chamber 23 and also bypassing the motor compartment 31. As in the second embodiment, a further vent line 17 is provided in the compressor housing 10. In the third embodiment, the distribution chamber 19 is connected to a respective further vent line 17 via one or more second vent lines 26b. The respective second vent line 26b extends through the joint gap formed by the main structure 21 and the additional structure 22. The respective second vent line 26b can be formed as a straight, advantageously radial passage in the joint gap.The respective second vent line 26b opens into the distribution chamber 19 at an inner circumference delimiting the distribution chamber 19, which the main structure 21 and the additional structure 22 jointly form, and radially further outwards at an outer circumference, which the main structure 21 and the additional structure 22 also jointly form, into the continuing vent line 17.

[0111] Fig.4 shows an example of use in which the gas compressor, indicated by the schematically illustrated compressor wheel 1, serves to supply a fuel cell 8 with a reaction gas. The gas compressor 1 is, as explained in the first exemplary embodiment, an integrated component of a supply module which comprises, as further integrated components, the electric drive motor 3 and the expander with the expander wheel 6. The gas compressor 1 conveys an oxygen-containing reaction gas G, for example fresh air, to the fuel cell 8, in which the oxygen contained in the reaction gas G reacts with hydrogen to form water. A mixture of unreacted reaction gas and water escapes from the fuel cell 8 at a pressure above the ambient temperature and is expanded as exhaust gas E in the expander of the supply module, thereby driving the expander wheel 6, the torque of which is used to rotate the compressor wheel 1.

[0112] On the other side of the fuel cell membrane, hydrogen, for example from a reservoir 7, is fed to the fuel cell 8, where it releases electrons. The remaining protons pass through the fuel cell membrane and react with oxygen atoms on the other side of the membrane to form water, which, as already mentioned, is discharged in the exhaust gas E via the expander of the supply module. The energy of the chemical fuel cell reaction is converted into electrical energy and made available via a converter 9 at a connection of the fuel cell 8. Reference symbol: 1 compressor wheel 1a nozzle or positioning sleeve 2 drive shaft 3 electric motor 4 Stator 5 Rotor 6 turbines 7 Shaft bearing structure 8 fuel cell 9 converters 10 Compressor housing 11 Compressor room 12 Gas inlet 13 Gas leak 14 Sealing gap 15 Rear wall 16 first vent line 17 continuing vent line 18 - 19 Distribution room 20 bearing housings 21 Main structure 22 Additional structure 23 storage room 24 storage foil 25 storage foil 26 second vent line 26a second vent line 26b second vent line 27 third vent line 28 Positioning element 29 Joining element, screw element 30 engine housing 31 Engine compartment 40 expander housings 41 Partition wall 42 Gas inlet 43 Gas leak 44 Joining element E exhaust G Gas, reaction gas R axis of rotation QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 4 067 669 A1

[0003] EP 2 772 652 A2

[0004]

Claims

[1] Gas compressor comprising: 1.1 a compressor housing (10) with a compressor chamber (11), a gas inlet (12) and a gas outlet (13), 1.2 a compressor wheel (1) which is arranged in the compressor chamber (11) so as to be rotatable about an axis of rotation (R) in order to convey a gas from the gas inlet (12) to the gas outlet (13), 1.3 a rear wall (15) which faces axially towards a rear side of the compressor wheel (1) and axially delimits the compressor chamber (11), 1.4 a drive shaft (2) for the compressor wheel (1), 1.5 a bearing housing (20) which is non-rotatably joined to the compressor housing (10) and / or the rear wall (15) for supporting the drive shaft (2), 1.6 wherein the bearing housing (20) comprises a main structure (21) and an additional structure (22) arranged axially between the rear wall (15) and the main structure (21), 1.7 a distribution chamber (19) which is bounded on one end face by the rear wall (15) and on an axially opposite end face by the additional structure (22), 1.8 a first vent line (16) extending in the region of the rear wall (15), preferably through the rear wall (15), and opening into the distribution chamber (19), through which leakage gas can be discharged from the rear side of the compressor wheel (1) into the distribution chamber (19), and 1.9 a second vent line (26; 26a: 26b), which also opens into the distribution chamber (19) in order to discharge the leakage gas from the distribution chamber (19), 1.10 wherein the additional structure (22) is formed separately from the compressor housing (10), the rear wall (15) and the main structure (21) and is joined in a rotationally immovable manner to at least one of the main structure (21), the compressor housing (10) and the rear wall (15). [2] Gas compressor according to claim 1, comprising a shaft bearing structure (7) which is axially immovably connected to the drive shaft (2), wherein a bearing space (23) remains axially between the main structure (21) and the additional structure (22), into which bearing space the shaft bearing structure (7) projects radially outwards in order to form an axial bearing (7, 24, 25), preferably an axial gas foil bearing (7, 24, 25), for the drive shaft (2) in the bearing space (23). [3] Gas compressor according to the preceding claim, wherein the second vent line (27) extends into the storage space (23). [4] Gas compressor according to one of the preceding claims, wherein the second vent line (26; 26a; 26b) extends through the bearing housing (20) or at a circumference of the bearing housing (20) into the distribution chamber (19). [5] Gas compressor according to one of the preceding claims, wherein the second vent line (26) extends through the additional structure (22) or at a periphery of the additional structure (22) into the distribution chamber (19). [6] Gas compressor according to one of the preceding claims, comprising an electric drive motor (3) and a motor housing (30) which is non-rotatably connected to the bearing housing (20) and / or the compressor housing (10) and surrounds a motor compartment (31) in which the drive motor (3) is arranged, wherein the distribution chamber (19) is connected directly or indirectly to the motor compartment (31) and / or the gas inlet (12) via the second vent line (26; 26a; 26b). [7] Gas compressor according to one of the preceding claims, in each case in combination with claim 2, comprising a third vent line (27) extending into the storage space (23) through which leakage gas can be discharged from the storage space (23), wherein the distribution chamber (19) is preferably connected to the engine compartment (31) via the third vent line (27). [8] Gas compressor according to the preceding claim, wherein the second vent line (26) and the third vent line (27) open into the bearing chamber (23) radially peripherally of the axial bearing (7, 24, 25). [9] Gas compressor according to one of claims 1 to 6, each in combination with claim 2, wherein the second vent line (26a; 26b) extends through the bearing housing (20) or at a periphery of the bearing housing (20), preferably through the main structure (21) or at a periphery of the main structure (21), into the distribution chamber (19) to discharge the leakage gas from the distribution chamber (19), and wherein the second vent line (26a; 26b) bypasses the bearing space (23). [10] Gas compressor according to one of the preceding claims, wherein the distribution chamber (19) extends radially outward further than the compressor wheel (1). [11] Gas compressor according to one of the preceding claims in combination with claim 2, wherein the distribution chamber (19) extends radially outwards further than the storage space (23). [12] Gas compressor according to one of the preceding claims, each in combination with claim 2, wherein the main structure (21) and the additional structure (22) form the bearing housing (20) in the form of a pre-assembled assembly unit in which the shaft bearing structure (7) is rotatably received axially between the main structure (21) and the additional structure (22), and wherein the drive shaft (2) can be inserted axially into the assembly unit and can thereby be coupled to the shaft bearing structure (7) in a rotationally immovable manner, or wherein the drive shaft (2) is already inserted axially into the assembly unit and is coupled to the shaft bearing structure (7) in a rotationally immovable manner. [13] Gas compressor according to one of the preceding claims, each in combination with claim 2, wherein the main structure (21) has an axial recess on an end face axially facing the rear wall (15) and the additional structure (22) delimits the recess on the end face, preferably closes it off, and thereby forms the storage space (23) with the main structure (21). [14] Fuel cell system with a gas compressor according to one of the preceding claims and a fuel cell which is connected to the gas outlet (13) so that the gas delivered by the gas compressor can be supplied to the fuel cell as a reaction gas. [15] Supply module comprising: 15.1 a gas compressor according to one of the preceding claims, 15.2 an electric drive motor (3) with a stator (4) and a rotor (5), and 15.3 a motor housing (30), wherein 15.4 the stator (4) is non-rotatably connected to the motor housing (30) and the rotor (5) is non-rotatably connected to the drive shaft (2), and 15.5 the compressor housing (10), the rear wall (15), the bearing housing (20) and the motor housing (30) are separately formed housing structures of a joined module housing. [16] Supply module according to the preceding claim, comprising an expander wheel (6) which is non-rotatably connected to the drive shaft (2), and as a further component of the module housing an expander housing (40, 41) for the expander wheel (6).

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