Compressor wheel assembly for fuel cell system side channel compressor, side channel compressor, fuel cell system, and method of assembling same

Abstract

The invention relates to a compressor wheel assembly for a side channel compressor of a fuel cell system for conveying and / or compressing a gaseous medium, in particular hydrogen. The compressor wheel assembly is rotatably supported about an axis of rotation and / or can be driven by a drive device. The compressor wheel assembly comprises a compressor wheel by means of which an air flow can be generated, in particular in a compressor chamber, a hub, a non-return ring and at least one bearing. The hub has a first shoulder and the compressor wheel has an annular continuation. According to the invention, a hub of the compressor wheel assembly has at least a first outer diameter region and a second outer diameter region. The hub has an external thread in a first outer diameter region and the compressor wheel has an internal thread at a first inner diameter region. And the hub and the compressor wheel are mutually screwed through the threads and form threaded connection. The invention also relates to a side channel compressor and / or a fuel cell system with a compressor wheel assembly according to the invention and / or a method for assembling a compressor wheel assembly.

Description

Technical Field

[0001] The present invention relates to a compressor wheel assembly for a side channel compressor of a fuel cell system, a side channel compressor and an assembly method of the compressor wheel assembly for the side channel compressor of a fuel cell system. In addition, the present invention also relates to a fuel cell system. Background Art

[0002] In addition to liquid fuels, gaseous fuels will also play an increasingly important role in the automotive sector of the future. In particular, in vehicles that use fuel cell drive, the flow of hydrogen must be controlled. The gas flow is no longer controlled discontinuously, as in the case of liquid fuel injection, but rather the gaseous medium is drawn from at least one high-pressure tank and fed to an injection device via an inflow line of a medium-pressure line system. The injection device feeds the gaseous medium to the fuel cell via a connecting line of a low-pressure line system. After flowing through the fuel cell, the gaseous medium is fed back to the injection device via a return line. A side channel compressor can be connected between the two to support the gas recirculation in terms of flow technology and efficiency. In addition, side channel compressors can be used to support the flow structure in the fuel cell drive, especially when the vehicle is (cold) started after a period of stationary operation. These side channel compressors are usually driven by an electric motor and are supplied with voltage from the vehicle battery during operation.

[0003] DE102022212235, which has not yet been published, discloses a side channel compressor for a fuel cell system, in which a gaseous medium, in particular hydrogen, is transported and / or compressed. The side channel compressor has a housing and a drive device, wherein the housing has an upper housing part and a lower housing part, the housing has a compressor chamber extending around the rotation axis, the compressor chamber has at least one surrounding side channel, and the housing has a compressor wheel, which is arranged to be rotatable around the rotation axis and driven by the drive device. The compressor wheel has blades arranged in the compressor chamber area on its circumference, and each blade has a gas inlet and a gas outlet formed on the housing, which are fluidically connected to each other through the compressor chamber, in particular at least one side channel, wherein the side channel compressor has at least one bearing. In addition, DE102022212235 also shows that the rotor assembly can be designed as a permanent magnet and is located on a drive flange corresponding to the hub.

[0004] The side channel compressor disclosed by DE102022212235 has certain disadvantages. The compressor wheel can be connected to the hub by a clearance fit. The clearance fit is produced between the second inner diameter region of the compressor wheel and the second outer diameter region of the hub (in particular the smaller outer diameter of the first shoulder region of the hub), between surfaces orthogonal to the axis of rotation. In an exemplary embodiment, the compressor wheel can be tightened to the hub by a plurality of bolt elements or screws, so that a first end face of the compressor wheel and a second end face of the hub form a force-fit connection, in particular orthogonal to the axis of rotation. The torque from the drive to the hub (for driving the side channel compressor) and from the hub to the compressor wheel is transmitted completely via the connection of the end faces. If a plurality of threaded connections are used, the preload force for supporting the compressor hub may not be large enough, in particular due to the surface pressure of the two end faces, which leads to displacement of the compressor hub. This may lead to a reduction or increase in the axial gap between the compressor wheel and the first and / or second housing part in the compressor chamber area, so that the compressor wheel collides with the housing parts, or the sealing of the side channels cannot be ensured, thereby reducing the conveying effect of the side channel compressor.

[0005] In addition, the position of the compressor wheel can change due to vibrations, causing the compressor wheel assembly to lose its balancing qualities (or balance quality). Large imbalances can also shorten the service life of the bearings and increase the probability of failure of the drive unit and, therefore, the entire side channel compressor. These effects are amplified by the clearance fit and the lack of support and / or guidance between the hub and the compressor wheel orthogonal to the axis of rotation. Summary of the invention

[0006] According to the present invention, a compressor wheel assembly for a side channel compressor of a fuel cell system is provided for conveying and / or compressing a gaseous medium, in particular hydrogen, and the compressor wheel assembly has the features of a preferred technical solution of the present invention. Here, the compressor wheel assembly is rotatably supported about a rotation axis and / or can be driven by a drive device, wherein the compressor wheel assembly has a compressor wheel (through which an air flow can be generated in a compressor chamber, in particular), a hub, a check ring, and at least one bearing. Here, the hub has a first shoulder and the compressor wheel has an annular continuation.

[0007] According to a preferred technical solution, the compressor wheel assembly includes a hub having at least a first outer diameter region and a second outer diameter region. The hub has an external thread in the first outer diameter region and the compressor wheel has an internal thread at the first inner diameter region. The hub and the compressor wheel are screwed together by threads and form a threaded connection. The advantage of this is that a preload, in particular a clamping force, can be achieved by screwing the compressor wheel directly onto the hub by means of internal and external threads and the threaded connection formed thereby. Compared with the use of multiple bolt elements (especially multiple bolt elements arranged around the axis of rotation), the threaded connection between the compressor wheel and the hub has a larger diameter, so that a greater preload can be obtained, thereby increasing the service life of the force-fit connection between the compressor wheel and the hub, wherein the first end face is strongly pressed against the second end face by the preload acting in the direction of the axis of rotation, thereby forming a reliable connection between the hub and the compressor wheel.

[0008] In addition, since the compressor wheel assembly of the present invention adopts a threaded connection design, it can prevent the compressor wheel from tilting or shifting on the hub, so that the compressor wheel will not shift on the hub. Therefore, the compressor wheel assembly designed according to the present invention can prevent the axial gap between the compressor wheel and the first and / or second shell parts in the compressor chamber area from becoming smaller or larger, so that the compressor wheel collides with the shell parts or the sealing of the side channels cannot be guaranteed. Therefore, the delivery effect of the side channel compressor can be maintained by using the compressor wheel assembly designed according to the present invention and the threaded connection designed according to the present invention. The service life of the compressor wheel assembly and the entire side channel compressor is also extended.

[0009] Furthermore, by means of a compressor wheel assembly designed according to the invention, the component complexity of the compressor wheel assembly can be reduced, since separate component screw connection elements, in particular a plurality of grub screws and corresponding clamping disks, can now be omitted and no additional components are required. This reduces component costs and / or assembly costs, thereby reducing the overall costs of the compressor wheel assembly and thus the costs of the entire side channel compressor.

[0010] The expansion scheme of the compressor wheel assembly and / or the side channel compressor given in the preferred technical solution can be realized through the measures listed in the optional technical solution.

[0011] According to an advantageous design, the hub of the compressor hub assembly has a second outer diameter region in the region of the second shoulder in addition to the first outer diameter region, wherein the compressor wheel has a second inner diameter region in addition to the first inner diameter region, wherein the hub with its second outer diameter region at least almost contacts the second inner diameter region orthogonally to the axis of rotation and / or forms a clearance fit orthogonal to the axis of rotation between the hub and the compressor wheel. In this way, the advantages of a compact design and space saving of the compressor wheel assembly can be achieved. As a result, the entire side channel compressor can also be designed to be more compact and space-saving. Another advantage is that, since the annular web of the compressor wheel can be centered on the second shoulder of the hub during assembly, the centering of the compressor wheel on the hub can be improved during assembly. This increases the ease of assembly, thereby reducing assembly costs and the probability of compressor wheel assembly failures due to assembly errors (e.g., unbalanced assembly of the compressor wheel due to uncentered assembly of the compressor wheel on the hub).

[0012] According to an advantageous development of the compressor wheel assembly, the threaded connection, in particular the internal thread and the external thread, is designed in a direction opposite to the rotation direction of the compressor wheel when the side channel compressor is in operation. This has the advantage that, since the threads of the hub and the compressor wheel are designed in a direction opposite to the rotation direction, loosening of the threaded connection can be prevented during operation of the side channel compressor. As a result, when the compressor wheel rotates during operation, the threaded connection is strengthened, thereby extending the service life of the compressor wheel assembly and / or the side channel compressor, and reducing the probability of failure of the compressor wheel assembly and / or the side channel compressor during operation due to loose threaded connections.

[0013] According to a particularly advantageous design of the compressor wheel assembly, the compressor wheel contacts the second end face of the second boss of the hub with the first end face of the annular web. These end faces are subjected to a preload at least parallel to the axis of rotation, so that a force-fit connection is formed between these end faces. In this way, the balancing quality of the compressor wheel assembly can be improved, thereby reducing the probability of failure of the compressor wheel assembly and / or each bearing and / or the entire side channel compressor. By reducing the imbalance of the compressor wheel assembly, the stress on the bearings will be less when running at high speeds, thereby extending the service life of the bearings and thus extending the service life of the entire side channel compressor. Assembly costs and / or maintenance costs can be reduced, thereby reducing the manufacturing cost and / or operating cost of the compressor wheel assembly, thereby also reducing the manufacturing cost and / or operating cost of the side channel compressor. In addition, a compact design of the compressor wheel assembly can be achieved.

[0014] According to an advantageous design of the compressor wheel assembly, the compressor wheel and / or the hub have holes, in particular assembly holes, which are at least almost parallel to the axis of rotation, by means of which holes it is possible to ensure a simplified assembly, in particular tightening, of the compressor wheel on the hub. This has the advantage that the preload force can be increased when screwing the compressor wheel onto the hub, since the compressor wheel and hub components can be better accommodated and / or screwed together with a tool via the holes. Due to the increased preload force, the compressor wheel assembly is less susceptible to displacements of the compressor wheel on the hub, in particular displacements orthogonal to the axis of rotation, which could lead to an imbalance of the compressor wheel assembly. Therefore, the compressor wheel assembly with holes designed according to the invention has the advantage of reducing the probability of failure of the compressor wheel assembly, thereby reducing the probability of failure of the entire side channel compressor and / or the entire fuel cell system. In addition, the initial imbalance can be reduced, thereby extending the service life of the entire side channel compressor.

[0015] According to an advantageous development of the compressor wheel assembly, the hub has a chamfer on its end face facing the annular web of the compressor wheel, which extends annularly around the axis of rotation. This has the advantage that the assembly of the compressor wheel on the hub and / or the positioning of the compressor wheel on the hub can be improved before the two components are screwed together, during the process of "contacting (or abutting)" the compressor wheel with the hub. This avoids assembly errors and thus reduces the probability of failure of the compressor wheel assembly and thus of the entire side channel compressor. In addition, the initial imbalance can be reduced, thereby extending the service life of the entire side channel compressor.

[0016] Since preferred fields of application of the compressor wheel assembly according to the invention are side channel compressors and / or fuel cell systems, a side channel compressor and / or a fuel cell system with a compressor wheel assembly according to the invention is also proposed.

[0017] According to an advantageous embodiment, a method for assembling a side channel compressor is provided. In a first method step, a hub with an external thread in a first outer diameter region and a compressor wheel with an internal thread in a first inner diameter region are provided. Then, in a second method step, the compressor wheel is brought into contact with the hub, in particular by centering on the chamfer. In a third method step, the compressor wheel and the hub are screwed to each other, so that these components are screwed to each other via the thread, thus forming a threaded connection.

[0018] In a fourth method step, a predetermined and / or maximum tightening torque is applied to the compressor wheel and / or the hub, so that the compressor wheel and / or the hub are loaded with a preload and pressed against the respective other element and a force-fit connection is formed between the first end face of the compressor wheel and the second end face of the hub. In a fifth method step, the corresponding components of the compressor wheel assembly are magnetized.

[0019] According to a second aspect of the present invention, a fuel cell system is provided. The fuel cell system comprises a fuel cell, the fuel cell having an oxygen inlet, a hydrogen inlet, an exhaust gas outlet, an anode, a cathode and an electrolyte. According to the present invention, the fuel cell system comprises a side channel compressor designed according to the present invention, the side channel compressor being connected to the exhaust gas outlet in a fluid communication manner.

[0020] According to the present invention, the fuel cell can also be designed as a fuel cell stack composed of a plurality of fuel cells. In this case, the fuel cell stack preferably has an exhaust gas outlet, and the side channel compressor of the present invention is connected to the exhaust gas outlet in a fluid-connected manner. The working chamber inlet of the side channel compressor is connected to the exhaust gas outlet in a fluid-connected manner so that the exhaust gas at the exhaust gas outlet can be sent into the working chamber of the side channel compressor. The fuel cell system preferably has a water separator, which is preferably arranged upstream of the flow direction of the side channel compressor. The working chamber outlet of the side channel compressor is preferably connected to the hydrogen inlet in a fluid-connected manner so as to transport the hydrogen in the side channel compressor to the fuel cell or the fuel cell of the fuel cell stack.

[0021] The fuel cell system of the present invention has all the advantages described for the compressor wheel assembly and / or the side channel compressor of the first aspect of the present invention. Therefore, compared with the conventional fuel cell system, the fuel cell system of the present invention has the advantage that an improved compressor wheel assembly with a lower probability of failure can be produced in an economical and effective manner by a simple method. In addition, the fuel cell system of the present invention is particularly easy to assemble and disassemble the compressor wheel assembly and / or the side channel compressor, so the assembly cost is low and maintenance is very easy. In addition, the fuel cell system according to the present invention has particularly low operating noise.

[0022] The present invention is not limited to the embodiments described herein and the aspects emphasized therein. On the contrary, numerous modifications are possible within the scope indicated by the claims, and these modifications are all within the scope of the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in more detail below with reference to the accompanying drawings.

[0024] In the attached figure:

[0025] Figure 1 A schematic cross-sectional view of a side channel compressor according to the prior art is shown;

[0026] Figure 2 A schematic cross-sectional view of a compressor wheel assembly according to the prior art is shown, which has a compressor wheel, a hub and a bearing;

[0027] Figure 3 A schematic cross-sectional view of a compressor wheel assembly according to the present invention is shown, which has a compressor wheel, a hub and a bearing;

[0028] Figure 4 A simplified flow chart for illustrating the method of the present invention is shown;

[0029] exist Figures 1 to 4 In the drawings, elements having the same function and mode of action are marked with the same reference numerals. DETAILED DESCRIPTION

[0030] exist Figure 1 , a side channel compressor 1 according to the prior art is schematically shown in the form of a sectional view. The side channel compressor 1 has a housing having a first housing part 3 and a second housing part 4. The first housing part 3 has a bearing journal 5 extending in the direction of the second housing part 4 and a bearing arrangement 9 arranged on the bearing journal 5, which has two rolling bearings 19, 20. In this case, the first bearing 19 and the second bearing 20 of the bearing arrangement 9 are arranged adjacent to each other in the direction of the rotation axis 46. In addition, a spacer disk 15 is arranged between the rolling bearings 19, 20, wherein in particular the bearing outer rings 11a, b are in axial contact with the spacer disk 15 relative to the rotation axis 46. The bearing inner ring 8 of each bearing 19, 20 is arranged on the bearing journal 5. A compressor wheel assembly 10 with a compressor wheel 34 is arranged on the bearing outer rings 11a, b of each bearing 19 and 20. In addition, the side channel compressor 1 has a compressor chamber 36 extending around the rotation axis 46, which has at least one surrounding side channel 35. In this case, the compressor wheel 34 is driven by a drive device 37.

[0031] like Figure 1 As shown, the side channel compressor has a blind hole in the bearing journal 5, in which a fastening element 28, in particular a clamping bolt 28, is arranged. The bearings 19, 20 are at least indirectly clamped on the first housing part 3 via the clamping bolt 28 and the spring element 18, wherein the first housing part 3 is at least indirectly clamped to the bearing arrangement 9 via the fastening element 28. In this case, by tightening the clamping bolt 28, a bearing preload acting parallel to the axis of rotation 46 is applied to the bearing arrangement 9. In addition, four axial gaps 33a, b, c, d are shown, which are distributed in the direction of the axis of rotation 46 in the region between the compressor wheel assembly 10, in particular the compressor wheel 34, and the respective housing part 3, 4, wherein the axial gaps 33a, b, c, d surround the compressor chamber 36.

[0032] In addition, if Figure 1As shown, the drive device 37 is designed as an axial magnetic field motor 37, which has a stator 37, wherein a magnetic field is formed by energizing the stator 37, and the magnetic field acts on the segmented magnets 42 of the compressor wheel assembly 10, thereby causing the compressor wheel assembly to be in a rotational motion. In an exemplary embodiment, the hub 7 may have an annular groove 45 extending around the rotation axis 46 (such as Figure 2 ), wherein the component check ring 40 and at least two segmented magnets 42 (preferably four segmented magnets 42) are at least almost completely located in the groove 45.

[0033] exist Figure 2 , a schematic cross-sectional view of a compressor wheel assembly 10 with a compressor wheel 34, a hub 7 and at least one bearing 19, 20 according to the prior art is shown. The compressor wheel assembly 10 shown in the figure is a component of a side channel compressor 1 for a fuel cell system 2, for conveying and / or compressing a gaseous medium, in particular hydrogen. The compressor wheel assembly 10 is rotatably supported about an axis of rotation 46 and can be driven by a drive device 37. The compressor wheel assembly 10 has a compressor wheel 34, through which an air flow can be generated in particular in a compressor chamber 36. In addition, the compressor wheel assembly 10 also has a hub 7, a check ring 40 and at least one bearing 19, 20. The compressor wheel assembly 10 is suitable for a side channel compressor 1. The side channel compressor 1 is suitable for a fuel cell system 2 for conveying and / or compressing a gaseous medium, in particular hydrogen. The compressor wheel assembly 10 is rotatably supported about an axis of rotation 46 and / or can be driven by a drive device 37, wherein the compressor wheel assembly 10 has a compressor wheel 34 (through which an air flow can be generated, in particular in a compressor chamber 36), a hub 7, a check ring 40 and at least one bearing 19, 20, wherein the hub 7 has a first shoulder 16 and a second shoulder 22, and the compressor wheel 34 has an annular extension 44.

[0034] The hub 7 has the first shoulder 16 and the compressor wheel 34 has the annular continuation 44, wherein the hub 7 and the compressor wheel 34 are screwed together by at least two screws 39, in particular two grub screws 39. The clamping disk 30 can be located between the head of each screw 39 and the hub 7 and / or the compressor wheel 34. During assembly, the compressor wheel 34 is pushed onto the hub 7 in the direction of the rotation axis 46 until the first end face 41 (e.g. Figure 3 ) and the second end face 43 (as shown) of the first boss 16 of the hub 7 Figure 3The two components are then screwed together by at least two screws 39 and the compressor wheel assembly 10 is formed. The compressor wheel assembly 10 according to the prior art has a clearance fit 38, wherein the clearance fit 38 is orthogonal to the rotation axis 46 between the second outer diameter region 23 of the first shoulder 16 of the hub 7 and the second inner diameter region 29 of the annular continuation 44 of the compressor wheel 34. This clearance fit 38 is necessary because the materials used for the compressor wheel 34 and the hub 7 are different, for example, the compressor wheel 34 has aluminum and the hub 7 has stainless steel. Due to the different thermal expansion coefficients, this leads to different thermal expansion during the operation of the side channel compressor 1. If the two components 7, 34 are in contact with their respective inner and outer diameters 23, 29 and no clearance fit 38 is formed, then movement of the components will occur when passing through a wide temperature range, for example, from 0°C to 80°C, and this movement may eventually lead to failure of the threaded connection, thereby causing damage and failure of the compressor wheel assembly 10. In addition, as Figure 2 As shown, the hub 7 has a groove 45 which extends annularly around the axis of rotation 46 , wherein the components of the check ring 40 and at least two segmented magnets 42 , preferably four segmented magnets 42 , are located at least almost completely in the groove 45 .

[0035] In addition, if Figure 2 As shown, the bearing stop disk 12 can be located between the fastening element 28 (especially the enlarged screw head) and the bearing journal 5 and / or the respective bearing inner ring 8 in the direction of the rotation axis 46. In addition, the bearing stop disk 12 is in contact with the surface of the bearing journal 5 at least indirectly via the spacer sleeve 14 in the direction of the rotation axis 46. Before the assembly is completed, by machining the spacer sleeve 14, the bearing preload of the respective bearing 19, 20 can now be achieved, which is achieved in particular by a bearing preload force.

[0036] Figure 3A schematic cross-sectional view of a compressor wheel assembly 10 according to the invention is shown, with a compressor wheel 34, a hub 7 and bearings 19, 20. As shown, the hub 7 of the compressor wheel assembly 10 has at least a first outer diameter region 21 and a second outer diameter region 23, wherein the hub 7 has an outer thread 26 in the first outer diameter region 21 and the compressor wheel 34 has an inner thread 32 at the first inner diameter region 27. The hub 7 and the compressor wheel 34 are screwed together by the threads 26, 32 and form a threaded connection 24. The compressor wheel 34 has an annular web 44, which extends annularly around the axis of rotation 46. Furthermore, the hub 7 has a second outer diameter region 23 in the region of the second shoulder 22 in addition to the first outer diameter region 21, wherein the compressor wheel 34 has a second inner diameter region 29 in addition to the first inner diameter region 27. In this case, the hub 7 is in contact with the second inner diameter region 29 at least almost perpendicular to the rotation axis 46 with its second outer diameter region 23, and / or a clearance fit 38 perpendicular to the rotation axis 46 is formed between the hub 7 and the compressor wheel 34. In addition, the hub 7 also has a third outer diameter region 25, wherein among the three outer diameter regions 21, 23, 25, the third outer diameter region 25 has the smallest diameter and the first outer diameter region 21 has the largest diameter.

[0037] In addition, if Figure 3 As shown, the threaded connection 24, in particular the internal thread 32 and the external thread 26, is designed in a direction opposite to the rotation direction of the compressor wheel 34 during operation of the side channel compressor 1. Therefore, the threaded connection 24 can be prevented from loosening during operation, because during operation of the side channel compressor, the compressor wheel rotates in the direction of rotation, and the compressor wheel assembly 10 designed according to the invention has a self-locking effect. In addition, as shown in the figure, the compressor wheel 34 is in contact with the second end face 43 of the second shoulder 16 of the hub 7 with the first end face 41 of its annular web 44, wherein the end faces 41, 43 are loaded by a preload 31 acting at least parallel to the rotation axis 46, so that a force-fit connection is formed between these end faces 41, 43. When the preload 31 is applied when the components 7, 34 are screwed together, the annular web 44 can be at least partially deformed, especially because the web 44 is elastic and / or has an elastic material, so that the clamping effect can be achieved over a wide temperature range. Thus, displacement of the compressor wheel 34 on the hub 7 (particularly orthogonal to the axis of rotation 46) can be prevented, in particular during magnetization of the compressor wheel assembly 10 during operation or during production of the side channel compressor 1. In addition, the compressor wheel assembly 10 designed according to the invention can also improve its balancing quality.

[0038] In addition, if Figure 3As shown, the compressor wheel assembly 10 is designed in an advantageous exemplary embodiment such that the compressor wheel 34 and / or the hub 7 have holes 6a, b, in particular assembly holes 6a, b, extending at least approximately parallel to the rotation axis 46, by means of which holes 6a, b a simplified assembly, in particular screwing, of the compressor wheel 34 on the hub 7 can be ensured. Here, an assembly tool can be inserted into at least one hole 6a of the compressor wheel 34 and at least one hole 6b of the hub 7, so that the two components 7, 34 are screwed together by means of corresponding threads 26, 32. In an exemplary embodiment of the compressor wheel assembly 10, the hub 7 can have a chamfer 47 on its second end face 43 facing the annular web 44 of the compressor wheel 34, wherein the chamfer 47 extends annularly around the rotation axis 46. By means of the chamfer 47, the installation and / or centering of the compressor wheel 34 and the hub 7 can be simplified. According to the design of the compressor wheel assembly 10 of the present invention, the threaded connection 24 is arranged in the hub 7, in particular in the first outer diameter region 21 of the hub 7, as far away from the bearings 19, 20 as possible, orthogonally to the rotation axis 46, so that the bearing hole will not be deformed. In this way, since the possibility of deformation of the bearing seat is low, the wear of the bearings 19, 20 is minimized, thereby extending the service life of the bearings 19, 20.

[0039] Figure 4 A simplified flow chart for illustrating the method of the present invention is shown. The method is used for assembling a compressor wheel assembly 10 of a side channel compressor 1 and / or a fuel cell system 2 and may include the following steps, in particular the assembly step:

[0040] - providing 101 a hub 7 with an external thread 26 in a first outer diameter region 21 and a compressor wheel 34 with an internal thread 32 in a first inner diameter region 27;

[0041] - bringing the compressor wheel 34 into contact with the hub 7 102 , in particular by centering on the chamfer 47 ;

[0042] - screwing 103 the compressor wheel 34 to the hub 7 so that these parts 7 , 34 are screwed together via the threads 26 , 32 so that the threads 26 , 32 form the threaded connection 24 ;

[0043] - applying 104 a predetermined and / or maximum tightening torque to the compressor wheel 34 and / or the hub 7, so that the compressor wheel 34 and / or the hub 7 are subjected to a preload force 31 and are pressed against the respective other element 7, 34, so that a force-fit connection is formed between the first end face 41 of the compressor wheel 34 and the second end face 43 of the hub 7;

[0044] - Magnetizing 105 the respective components 40 , 42 of the compressor wheel assembly 10 .

Claims

1. A compressor wheel assembly (10) for a side channel compressor (1) of a fuel cell system (2) for conveying and / or compressing a gaseous medium, in particular hydrogen, wherein the compressor wheel assembly (10) is rotatably supported about an axis of rotation (46) and / or can be driven by a drive device (37), wherein the compressor wheel assembly (10) comprises a compressor wheel (34), a hub (7), a check ring (40) and at least one bearing (19, 20), through which an air flow can be generated, in particular in a compressor chamber (36), wherein the hub (7) has a first shoulder (16) and the compressor wheel (34) has an annular continuation (44), characterized in that The hub (7) of the compressor wheel assembly (10) has at least a first outer diameter region (21) and a second outer diameter region (23), wherein the hub (7) has an outer thread (26) in the first outer diameter region (21) and the compressor wheel (34) has an inner thread (32) at the first inner diameter region (27), wherein the hub (7) and the compressor wheel (34) are screwed together via the threads (26, 32) and form a threaded connection (24).

2. The compressor wheel assembly (10) according to claim 1, characterized in that The hub (7) has, in addition to the first outer diameter region (21), a second outer diameter region (23) in the region of the first shoulder (16), wherein the compressor wheel (34) has, in addition to the first inner diameter region (27), a second inner diameter region (29), wherein the hub (7) with its second outer diameter region (23) at least almost contacts the second inner diameter region (29) orthogonally to the rotation axis (46), and / or a clearance fit (38) orthogonally to the rotation axis (46) is formed between the hub (7) and the compressor wheel (34).

3. The compressor wheel assembly (10) according to claim 1 or 2, characterized in that The threaded connection (24), in particular the internal thread (32) and the external thread (26), are designed to be opposite to the direction of rotation of the compressor wheel (34) during operation of the side channel compressor (1).

4. The compressor wheel assembly (10) according to any one of the preceding claims, characterized in that The compressor wheel (34) contacts the second end face (43) of the second shoulder (16) of the hub (7) with a first end face (41) of the annular web (44), wherein the end faces (41, 43) are loaded by a preload force (31) acting at least parallel to the rotation axis (46), thereby forming a force-fitting connection between the end faces (41, 43).

5. The compressor wheel assembly (10) according to any one of the preceding claims, characterized in that The compressor wheel (34) and / or the hub (7) have holes (6a, b), in particular assembly holes (6a, b), which extend at least approximately parallel to the rotation axis (46), and by means of which holes (6a, b) a simplified assembly, in particular screwing, of the compressor wheel (34) on the hub (7) can be ensured.

6. The compressor wheel assembly (10) according to any one of the preceding claims, characterized in that The hub (7) has a chamfer (47) on its end face facing the annular web (44) of the compressor wheel (34), wherein the chamfer (47) extends annularly around the axis of rotation (46).

7. A side channel compressor (1) comprising a compressor wheel assembly (10) according to any one of claims 1 to 6.

8. A fuel cell system (2) comprising a side channel compressor (1) according to claim 7, wherein the side channel compressor (1) is arranged in an anode circuit of the fuel cell system (2).

9. A method for assembling a compressor wheel assembly (10) for a side channel compressor (1) and / or a fuel cell system (2) according to one of the preceding claims, comprising the following steps: - providing (101) a hub (7) with an external thread (26) in a first outer diameter region (21) and a compressor wheel (34) with an internal thread (32) in a first inner diameter region (27); - bringing the compressor wheel (34) into contact (102) with the hub (7), in particular by centering on the chamfer (47); - screwing (103) the compressor wheel (34) to the hub (7) so that the components (7, 34) are screwed to one another via the threads (26, 32) so that the threads (26, 32) form a threaded connection (24); - applying (104) a predetermined and / or maximum tightening torque to the compressor wheel (34) and / or the hub (7), so that the compressor wheel (34) is subjected to a preload force (31) and is pressed against the hub (7), thereby forming a force-fit connection between a first end face (41) of the compressor wheel (34) and a second end face (43) of the hub (7); - magnetizing (105) the corresponding components (40, 42) of the compressor wheel assembly (10).

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