Side channel compressor and fuel cell system

Abstract

Side channel compressor (1) for a fuel cell system (2) for compressing a gaseous medium, comprising a housing with a first housing part (3) and a second housing part (4), wherein the first housing part (3) has a bearing journal (5) extending along an axis of rotation (R) with a journal root section (6) and a journal main section (7), wherein a bearing inner ring (8) of a bearing device (9) is arranged on the journal main section, wherein a compressor wheel assembly (10) with a compressor wheel (34) is rotatably arranged inside the housing on a bearing outer ring (11) of the bearing device (9) about the axis of rotation (R).According to the invention, the first housing part (3) is clamped at least indirectly to the bearing device (9) via a fastening element (28), wherein a spring element (18) is arranged on the pin root section (6) between a contact surface (40) of the inner bearing ring (8) facing away from the fastening element (28) and an inner wall (17) of the first housing (3) facing the fastening element (28), wherein a spring element cap (13) is arranged in the direction of the axis of rotation R between the spring element (18) and the inner bearing ring (8) and the spring element cap (13) is in contact with the spring element (18) and the inner bearing ring (8). The invention further relates to a fuel cell system (2) with a side channel compressor (1) according to the invention.

Description

[0001] The present invention relates to a side channel compressor for a fuel cell system for compressing a gaseous medium. Furthermore, the invention relates to a fuel cell system with a side channel compressor of this type. State of the art

[0002] Rising fuel prices and legal requirements to limit CO2 emissions are prompting automobile manufacturers to increasingly develop drive systems using renewable energy sources. Hydrogen technology offers a promising approach for several reasons, as hydrogen is virtually unlimited as an energy source and its combustion produces no harmful emissions.

[0003] While the direct combustion of hydrogen is a highly complex and currently almost impossible to control process, drive systems are gaining increasing importance in which hydrogen is first used to generate electrical energy, which can then be used to operate an electric motor to power the vehicle. These drive systems incorporate a fuel cell for this purpose.

[0004] By design, fuel cell systems have a hydrogen inlet through which hydrogen can be fed into the fuel cell. On the hydrogen inlet side, fuel cell systems have an anode. For supplying oxygen, fuel cell systems have an oxygen inlet. On the oxygen inlet side, fuel cell systems have a cathode. Finally, fuel cell systems have an exhaust outlet for discharging the fuel cell's exhaust gases. These gases primarily consist of water, a combustion product of the fuel cell, and unused air. Since not all of the hydrogen fed into the fuel cell is combustible during the reaction within the fuel cell, the exhaust gases also include unburned or unused hydrogen.

[0005] To reduce hydrogen consumption in fuel cells, it is now common practice to recirculate unused hydrogen. Recirculation blowers, sometimes featuring so-called "side-channel compressors," are used for this recirculation.

[0006] Side channel compressors come in various designs. Side channel compressors are a type of centrifugal compressor, which can be divided into "star wheel compressors" and "peripheral wheel compressors" based on the impeller used and the fluid flow.

[0007] The fluid to be pumped is fed into a working chamber of the side channel compressor via an inlet connection, which is fluidly coupled to the exhaust outlet of the fuel cell system. A compressor wheel assembly of the side channel compressor, designed as an impeller, is arranged in the working chamber. This compressor wheel assembly is driven by an electric motor and thus rotates. The compressor wheel assembly rotates to axially arranged, one-sided or two-sided lateral flow channels, which are also referred to as "side channels."

[0008] In this way, the rotating compressor wheel assembly transfers energy to a portion of the flow. The fluid circulates in the blades of the compressor wheel assembly and in the side channels, forming a circulation flow. From this circulation flow, the energy is transferred to the flow in a side channel through momentum exchange. This results in a conversion of velocity energy into pressure energy. The energy transfer occurs multiple times along the entire length of the side channel, allowing for a large energy transfer. This results in a pressure increase at an outlet nozzle of the side channel compressor compared to the inlet nozzle.

[0009] A conventional side channel compressor is known from document DE 10 2018 222 102 A1. The side channel compressor can have the disadvantage that the use of an axial fixation of the rolling bearings on a bearing journal of the housing lower section leads to severe tension and thus to an excessive bearing preload. In particular, due to a preload force of the fixing element, which is designed, for example, as a central screw. This can lead to damage to a bearing device due to a clamping force from the bearing rings, in particular a respective bearing inner ring and a bearing outer ring, whereby the rolling bearing bodies inside the bearing are damaged. This leads to a reduced bearing service life and thus an increased probability of failure of the side channel compressor. DE 10 2018 207 891 A1 also discloses a side channel compressor in which a spring element is located between a housing part and a bearing.This can lead to damage to the spring element if the inner and / or outer bearing rings rotate as intended, as the spring element also rotates. If the spring element is designed as a wave spring, the wave spring can twist open, causing severe damage and / or failure of the wave spring and thus the side channel compressor. Disclosure of the invention

[0010] The present invention relates to a side channel compressor for a fuel cell system for compressing a fluid, having the features of independent claim 1, and to a fuel cell system with a side channel compressor, having the features of independent claim 9. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the side channel compressor according to the invention naturally also apply in connection with the fuel cell system according to the invention, and vice versa, so that reciprocal reference is or can always be made to the individual aspects of the invention with regard to the disclosure.

[0011] According to a first aspect of the invention, a side channel compressor for a fuel cell system for compressing a gaseous medium is provided. The side channel compressor comprises a housing with a first housing part and a second housing part, wherein the first housing part has a bearing journal extending along a rotational axis R and having a journal root section and a journal main section. A bearing inner ring of a bearing device is arranged on the journal main section, wherein a compressor wheel assembly with a compressor wheel is arranged within the housing on a bearing outer ring of the bearing device so as to be rotatable about the rotational axis R.

[0012] The housing is formed by the first housing part and the second housing part. It can be provided according to the invention, but is not absolutely necessary, that the first housing part and / or the second housing part have further housing parts, which can in particular be designed as a housing cover, housing wall or the like. Preferably, the first housing part defines a pre-assembled assembly of the side channel compressor, which has the bearing device and the compressor wheel assembly. A working space for the compressor wheel assembly is formed by the housing, preferably through the interaction of the first housing part with the second housing part.

[0013] The working chamber is preferably fluid-tight, except for a working chamber inlet and a working chamber outlet. Within the scope of the invention, fluid-tight also means that the seal is maintained at a working pressure of the silk-channel compressor that is higher than the ambient pressure. To ensure the seal, sealing devices, such as sealing rings, in particular made of silicone or rubber, or the like, are preferably provided between the first housing part and the second housing part. The first housing part is preferably formed substantially or predominantly from aluminum. The second housing part is preferably formed substantially or predominantly from aluminum.

[0014] The bearing journal is formed as a partial region of the first housing part and extends from an inner wall of the first housing part. According to the invention, the bearing journal is formed monolithically with the first housing part. Alternatively, the bearing journal can also be arranged on the first housing part in a materially bonded manner, for example by welding, or in a force-fitting manner, for example by screwing or pressing. The bearing journal extends from the inner wall of the first housing part, from the journal root section, via the journal main section, to the journal end section. The journal end section has the journal clamping section. The journal end section is preferably designed as a journal clamping section.

[0015] The bearing device comprises the bearing inner ring and the bearing outer ring. Preferably, several rolling elements, such as balls, rollers, barrels, or the like, are arranged between the bearing inner ring and the bearing outer ring to support the bearing outer ring on the bearing inner ring with as little play as possible and to ensure relative rotation between the bearing inner ring and the bearing outer ring.

[0016] The bearing inner ring of the bearing device is arranged on the main journal section, preferably with a loose fit. Multiple bearing inner rings can also be arranged on the main journal section, preferably each with a loose fit. The loose fit is preferably designed in such a way that, when the clamping is released, easy movement of the bearing device on the bearing journal, for example, by hand, is ensured, and tilting of the bearing inner ring on the bearing journal is prevented.

[0017] The compressor wheel assembly is arranged on the outer bearing ring of the bearing device, preferably with a press fit. The press fit is preferably designed in such a way that displacement of the compressor wheel assembly on the bearing device is prevented by force-locking. Alternatively, the compressor wheel assembly can be arranged loosely on the outer bearing ring and secured by retaining means against axial slippage from the bearing device.

[0018] With reference to claim 1, the side channel compressor is designed such that the first housing part is clamped at least indirectly to the bearing device via a fastening element, wherein a spring element is arranged on the journal root section between a contact surface of the bearing inner ring facing away from the fastening element and the inner wall of the first housing facing the fastening element, wherein a spring element cap is arranged in the direction of the rotation axis R between the spring element and the bearing inner ring, and the spring element cap is in contact with the spring element and the bearing inner ring. In this way, the advantage can be achieved that any excessive bearing preload can be compensated for via the spring element.The spring tension can compensate for excessive bearing preloads caused by adverse tolerance chains, particularly in the direction of the rotation axis R, of the fastening element and / or stop disc and / or bearing device and / or spacer disc components. This increases the service life of the bearing device, thereby reducing the probability of failure of the side channel compressor and thus of the fuel cell system. Furthermore, the use of the spring element cap, which is located between the bearing inner ring and the spring element in the direction of the rotation axis and in contact with them, prevents direct contact between the bearing inner ring and the spring element.In the event of any rotation of the bearing inner ring, there is no frictional contact with the spring element, which does not rotate. Instead, the bearing inner ring is in frictional contact with the spring element cap, which can in particular be made of a hardened and therefore less wear-susceptible material, particularly in the frictional contact area. The spring element cap is not rotating, and thus there is no frictional contact between the spring element and the spring element cap. In this way, wear on the spring element is prevented and, in particular, shifted to the spring element-cap component, whereby a spring element made of spring steel, in particular, can be susceptible to frictional wear. This can increase the service life of the spring element and thus of the entire side channel blower.

[0019] The measures listed in the subclaims enable advantageous developments of the conveying device specified in claim 1. The subclaims relate to preferred developments of the invention.

[0020] According to an advantageous embodiment of the side channel compressor, the spring element cap has a sleeve-shaped shoulder which runs in a sleeve-like manner around the rotation axis R, wherein the spring element cap at least partially encloses the spring element on its outer diameter facing away from the rotation axis R with the sleeve-shaped shoulder. In this way, the advantage can be achieved that a simplified assembly of the spring element with the spring element cap can be achieved, since both components can be installed as an assembly combination in the side channel compressor. This can reduce assembly costs. Furthermore, the spring element can be guided better in the direction of the rotation axis R by the sleeve-shaped shoulder, which at least partially encloses the spring element, wherein the spring element is guided orthogonally to the rotation axis R by the sleeve-shaped shoulder of the spring element cap.

[0021] In this way, the probability of damage to the spring element can be reduced, thereby reducing the probability of failure of the entire side channel compressor.

[0022] According to an advantageous development of the side channel compressor, the spring element cap has an annular shoulder which runs in a ring-shaped manner around the rotation axis R, wherein the spring element cap with its annular shoulder is in contact with the bearing inner ring and the spring element axially to the rotation axis R and / or is arranged between the bearing inner ring and the spring element. In this way, the advantage can be achieved that the spring element is not in direct contact and / or contact with the bearing inner ring, since the annular shoulder is located between the bearing inner ring and the spring element. This prevents the spring element from "rotating" with the bearing inner ring, which could rotate relative to the bearing journal in certain operating states of the side channel compressor, because this "rotation" is absorbed and thus compensated for by the spring element cap.Furthermore, a spatial separation of the bearing seal from the spring element can be achieved, thus preventing potential damage to the bearing seal, which rotates with the bearing outer ring, caused by a stationary spring element, particularly through frictional contact. This allows the service life of the spring element and / or the bearing seal and / or the bearing device to be extended, thereby reducing the probability of failure of the side channel compressor.

[0023] According to a particularly advantageous embodiment of the side channel compressor, it has a contact disk, wherein the contact disk is arranged in the direction of the axis of rotation R between the spring element and the inner wall of the first housing part and wherein the contact disk is in contact with the spring element and the inner wall. In this way, the advantage can be achieved that the spring element is not in direct contact, in particular frictional contact, with the first housing part, in particular the inner wall. The contact disk is located between the spring element and the first housing part. This can prevent wear, in particular frictional wear, at this contact point. In addition, the contact disk can be made of a specially hardened material, so that at least almost no material is removed.Without the support disc, the spring element would remove material, a process known as "digging in," on the first housing section. This would, on the one hand, result in the creation of chips that could damage the bearing assembly and other components of the side channel compressor. On the other hand, the spring element would elongate due to the digging in, so that the preload acting on the bearing assembly would decrease. Since the use of the support disc prevents the spring element from "digging in," the probability of failure of the spring element, the bearing assembly, and the entire side channel compressor is reduced.

[0024] In a particularly preferred embodiment of the invention, the spring element in a side channel compressor can be designed as a wave spring. A wave spring is inexpensively available and has a characteristic curve that is advantageous for this application. This has the advantage that a reliable and constant provision of the clamping force and / or bearing preload is ensured by the wave spring using simple means and in a cost-effective manner.

[0025] According to a particularly advantageous embodiment of the side channel compressor, the sleeve-shaped shoulder has a height h running in the direction of the axis of rotation R, wherein the height h runs in the direction of the axis of rotation R and wherein the height h covers at least two turns of the wave spring. In this way, the advantage can be achieved that an expansion of the wave spring in diameter, in particular of individual turns of the wave spring, is prevented by the sleeve-shaped shoulder enclosing the wave spring from the outside and thus stabilizing it. Expansion of the wave spring is thus prevented because the solid spring comes into contact with the sleeve-shaped shoulder at an early stage during expansion, thus guiding the component and preventing further expansion. This can prevent damage to the wave spring, which would ultimately lead to failure of the bearing device and the side channel compressor.

[0026] According to a particularly advantageous development of the side channel compressor, a distance L between the first end face of the stop disk and the inner wall of the first housing part can be adjusted by using the contact disk with a respective adjustable width dimension bn, wherein the contact disk is located between the fastening element and the bearing device in the direction of the rotation axis R. In this way, the advantage can be achieved that an alignment of the compressor wheel assembly and an adjustment of a respective axial gap dimension and / or an axial stop of the bearing device is possible through the use of the contact disk with different width dimensions bn. By varying the respective width dimension bn, existing tolerance fluctuations of the bearing device and / or spring element cap and / or spring element and / or housing can be compensated.This also has the advantage that preload can be easily adjusted or limited by selecting a suitable thickness bn of the bearing disc using simple and cost-effective means. This allows manufacturing tolerances to be compensated for and excessive preload to be avoided. This also offers the advantage of achieving optimal bearing preload through appropriate pairing of the bearing disc and spring element components. This increases the service life of the bearing device and the entire side channel blower.

[0027] According to the invention, it is preferred that the bearing device comprises two rolling bearings arranged side by side along the rotational axis R. Inner spacer rings are preferably arranged between adjacent bearing inner rings. Outer spacer rings are preferably arranged between adjacent bearing outer rings. This has the advantage that pivoting of the compressor wheel assembly relative to the rotational axis R is better prevented using simple means and in a cost-effective manner. Wear on the bearing device can thus be reduced and its service life can be increased. Furthermore, the smooth running of the side channel compressor can be improved in this way.

[0028] According to a second aspect of the invention, a fuel cell system is provided. The fuel cell system comprises a fuel cell with an oxygen inlet, a hydrogen inlet, an exhaust gas outlet, an anode, a cathode, and an electrolyte. According to the invention, the fuel cell system comprises a side-channel compressor according to the invention that is fluidly coupled to the exhaust gas outlet.

[0029] According to the invention, the fuel cell can also be designed as a fuel cell stack comprising a plurality of fuel cells. In this case, it is preferred that the fuel cell stack has the exhaust outlet to which the side channel compressor according to the invention is fluidly coupled. The working chamber inlet of the side channel compressor is fluidly coupled to the exhaust outlet, so that exhaust gas from the exhaust outlet can be fed to the working chamber of the side channel compressor. The fuel cell system preferably has a water separator, which is preferably arranged upstream of the side channel compressor in the flow direction. The working chamber outlet of the side channel compressor is preferably fluidly coupled to the hydrogen inlet, so that hydrogen from the side channel compressor can be fed to the fuel cell or the fuel cells of the fuel cell stack.

[0030] The fuel cell system according to the invention provides all of the advantages already described for a side channel compressor according to the first aspect of the invention. Accordingly, the fuel cell system according to the invention has the advantage over conventional fuel cell systems that an improved arrangement of the bearing device on the bearing journal of the side channel compressor is ensured using simple means and in a cost-effective manner. By arranging the journal clamping section next to the bearing device, widening of the bearing journal during clamping or operation of the side channel compressor due to different thermal expansion coefficients of these components can be avoided or at least significantly reduced. Thus, stress on the bearing device can be reduced, and the service life of the bearing device can be significantly extended compared to conventional side channel compressors.Furthermore, the fuel cell system according to the invention features particularly simple assembly and disassembly of the side channel compressor, making it cost-effective to install and very easy to maintain. Furthermore, the fuel cell system according to the invention exhibits particularly low operating noise.

[0031] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, numerous modifications are possible within the scope of the claims, which are within the scope of one skilled in the art. Short description of the drawing

[0032] The invention is described in more detail below with reference to the drawing.

[0033] It shows: Fig. 1 shows a sectional view of a side channel compressor according to the prior art, Fig. 2 in a sectional view a Fig. 1 section of the side channel compressor marked II with at least one bearing and one spring element according to the state of the art, Fig. 3 in a sectional view a Fig. 1 section of the side channel compressor according to the invention, designated II, with at least the bearing, the spring element, a spring element cap and a contact disc, Fig. 4 shows a plan view of a fuel cell system according to a preferred embodiment of the invention.

[0034] Elements with the same function and mode of action are listed in the Fig. 1 to 4 are each provided with the same reference numerals.

[0035] In Fig. 1 shows a schematic sectional view of a side channel compressor 1 according to the prior art. The side channel compressor 1 has a housing with 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 device 9 with two rolling bearings 20 arranged on the bearing journal 5. The first bearing 20a and the second bearing 20b of the bearing device 9 are arranged next to one another in the direction of a rotation axis R. In addition, a spacer disk 15 is located between the rolling bearings 20a, b, wherein in particular the bearing outer rings 11a, b bear against the spacer disk 15 axially to the rotation axis R.

[0036] Bearing inner rings 8 of the bearing device 9 are arranged on the bearing journal 5. A compressor wheel assembly 10 with a compressor wheel 34 is arranged on bearing outer rings 11 of the bearing device 9. In addition, the side channel compressor 1 has a compressor chamber 36 extending circumferentially around the rotation axis R, which has at least one circumferential side channel 35.

[0037] As in Fig. 1, the bearing journal 5 has a blind hole in which a fastening element 28, in particular a clamping bolt 28, is arranged. The bearings 20 are clamped at least indirectly to the first housing part 3 via the clamping bolt 28 and a spring element 18, wherein the first housing part 3 is clamped at least indirectly to the bearing device 9 via the fastening element 28. A stop disk 19 can be arranged in the direction of the rotation axis R between the fastening element 28, in particular an enlarged screw head, and the bearing journal 5 and / or the respective bearing inner ring 8.

[0038] By screwing in the clamping bolt 28, a preload force 39 acting parallel to the rotation axis R is applied to the bearing device 9. Furthermore, it is shown that in the direction of the rotation axis R, four axial gaps 33a, b, c, d are located in the area between the compressor wheel assembly 10 and a respective housing part 3, 4, wherein the axial gaps 33a, b, c, d encapsulate the compressor chamber 30. The bearing journal 5 has an inner wall 17 (shown in Fig. 2) of the first housing part 3, and a journal main section 7 directly adjacent to the journal root section 6. Two bearing inner rings 8 of two rolling bearings 20 are arranged on the journal main section 7.

[0039] Fig. 2 shows a sectional view of a Fig. 1 shows a section of the side channel compressor 1, designated II, with at least one bearing and a spring element according to the prior art. It is shown that the second bearing 20b has the bearing outer ring 11b and the bearing inner ring 8b. The bearing outer ring 11b is in contact with the spacer disk 15 in the direction of the rotation axis R. At least one bearing seal 42 is located between the bearing inner ring 8b and the bearing outer ring 11b in order to encapsulate the interior of the bearing, wherein in particular a lubricant is prevented from escaping from the interior of the bearing, but also contamination of the interior of the bearing by particles from outside the respective bearing is prevented. The bearing inner ring 8b is in contact at least indirectly with a spring element 18 in the direction of the rotation axis R.The spring element 18 is supported on one side on a contact surface 40 of the bearing inner ring 8b and on the other side on the inner wall 17 of the first housing part 3. The spring element 18 acts with a spring force acting at least almost in the direction of the axis of rotation R in the area of ​​the contact points of the spring element 18 with the contact surface 40 and / or the inner wall 17. In this case, a respective wear area 41 can form in which the spring element 18, which consists of a harder material than the friction partners, damages the friction partners 8b, 3 and can lead to material removal, in particular in the respective wear area 41. Increased wear can occur if the bearing inner ring 8b, which should not rotate on the bearing journal 5 during normal operation, does rotate at certain operating points of the side channel compressor 1. This rotation can lead to considerable wear on the bearing inner ring 8b and / or the spring element 18.Furthermore, the spring element 18, which in one exemplary embodiment is designed as a wave spring 18, can unwind due to the rotation of the bearing inner ring 8b. This unwound coil could damage the bearing seal 42.

[0040] Fig. 3 shows a sectional view of a Fig. 1 shows a section, designated II, of the side channel compressor 1 according to the invention with the at least one bearing 20, the spring element 18, a spring element cap 13 and a contact disk 38. It is shown that the spring element cap 13 is arranged in the direction of the axis of rotation R between the spring element 18 and the bearing inner ring 8 and that the spring element cap 13 is in contact with the spring element 18 and the bearing inner ring 8. The spring element cap 13 has a sleeve-shaped shoulder 14 which runs in a sleeve-shaped manner around the axis of rotation R, the spring element cap 13 at least partially enclosing the spring element 18 with the sleeve-shaped shoulder 14 on its outer diameter facing away from the axis of rotation R.In this way, the spring element 18 can be protected against expansion, which is particularly advantageous in a design as a wave spring 18, since the spring element 18 is limited and / or guided outwardly from the rotation axis R by the sleeve-shaped shoulder 14. In the event of expansion, the spring element 18 abuts against the sleeve-shaped shoulder 14 and would be prevented from expanding further.

[0041] Furthermore, in Fig. 3 shows that the spring element cap 13 has an annular projection 16 which runs in a ring-shaped manner around the axis of rotation R, the spring element cap 13 with its annular projection 16 being in contact with the bearing inner ring 8 and the spring element 18 axially to the axis of rotation R and / or being arranged between the bearing inner ring 8 and the spring element 18. The side channel compressor 1 can have a contact disk 38, the contact disk 38 being arranged in the direction of the axis of rotation R between the spring element 18 and the inner wall 17 of the first housing part 3 and the contact disk 38 being in contact with the spring element 18 and the inner wall 17. In an exemplary embodiment, the spring element 18 can be designed as a corrugated spring 18.Furthermore, the sleeve-shaped shoulder 14 can have a height h running in the direction of the rotation axis R, wherein the height h runs in the direction of the rotation axis R and wherein the height h covers at least two turns of the corrugated spring 18.

[0042] In addition, Fig. 3 shows that by using the contact disc 38 with a respective adjustable width dimension bn, a distance L between a first end face 37 of the stop disc 19 and the inner wall 17 of the first housing part 3 can be adjusted, wherein the contact disc 38 is located in the direction of the rotation axis R between the fastening element 28 and the bearing device 9, in particular a first roller bearing 20a. In this case, the spring element 18 presses the compressor wheel assembly 10 against the contact disc 38. In this case, the compressor wheel 34 (shown in Fig. 1) to the first housing part 3 and to the second housing part 4 and stator housing such that the respective axial gaps 33 a, b, c, d (shown in Fig. 1) have at least approximately the same dimensions and lie within the tolerances to avoid collision between the compressor wheel 34 and the respective housing part 3, 4, while the gap is not so large that encapsulation of the compressor chamber 36 can be ensured due to excessive gap dimensions. The respective bearing inner ring 8 of the respective rolling bearing 20 should not rotate, as this could lead to wear between the spring element 18, in particular the wave spring 18, and the respective bearing inner ring 8, as well as the first housing part 3. This rotation led to considerable wear on the spring element 18.

[0043] In Fig.Figure 4 shows a schematic plan view of a fuel cell system 2 according to a preferred embodiment of the invention. The fuel cell system 2 comprises a fuel cell 21 with an anode 25 and a cathode 26, which are surrounded by an electrolyte 27. A membrane 29 is arranged between the anode 25 and the cathode 26.

[0044] Adjacent to the anode 25, the fuel cell 21 has a hydrogen inlet 23 for supplying hydrogen. Adjacent to the cathode 26, the fuel cell 21 has an oxygen inlet 22 for supplying oxygen or an oxygen-containing gas mixture, such as filtered air, as well as an exhaust gas outlet 24 for discharging exhaust gases from the fuel cell 21. A water separator 30 for separating water from the exhaust gas and the side channel compressor 1 according to the invention are arranged at the exhaust gas outlet 24.

[0045] A working chamber inlet 31 of the side channel compressor 1 is fluidly coupled to the exhaust gas outlet 24, so that exhaust gas from the exhaust gas outlet 24 can be fed to a working chamber of the side channel compressor 1 for compression via the working chamber inlet 31. A working chamber outlet 32 ​​of the side channel compressor 1 is fluidly coupled to the hydrogen inlet 23, so that hydrogen from the working chamber can be fed back to the fuel cell 21 via the working chamber outlet 32 ​​and the hydrogen inlet 23. 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] DE 10 2018 222 102 A1

[0009] DE 10 2018 207 891 A1

[0009]

Claims

[1] Side channel compressor (1) for a fuel cell system (2) for compressing a gaseous medium, comprising a housing with a first housing part (3) and a second housing part (4), wherein the first housing part (3) has a bearing journal (5) extending along a rotational axis (R) with a journal root section (6) and a journal main section (7), wherein a bearing inner ring (8) of a bearing device (9) is arranged on the journal main section (7), wherein a compressor wheel assembly (10) with a compressor wheel (34) is arranged within the housing on a bearing outer ring (11) of the bearing device (9) so as to be rotatable about the rotational axis (R), characterized byin that the first housing part (3) is clamped at least indirectly to the bearing device (9) via a fastening element (28), a spring element (18) being arranged on the journal root section (6) between a contact surface (40) of the bearing inner ring (8) facing away from the fastening element (28) and an inner wall (17) of the first housing part (3) facing the fastening element (28), a spring element cap (13) being arranged in the direction of the axis of rotation R between the spring element (18) and the bearing inner ring (8), and the spring element cap (13) being in contact with the spring element (18) and the bearing inner ring (8). [2] Side channel compressor (1) according to claim 1, characterized bythat the spring element cap (13) has a sleeve-shaped shoulder (14) which runs in a sleeve-shaped manner around the rotation axis R, wherein the spring element cap (13) at least partially encloses the spring element (18) on its outer diameter facing away from the rotation axis R with the sleeve-shaped shoulder (14). [3] Side channel compressor (1) according to claim 1 or 2, characterized by that the spring element cap (13) has an annular projection (16) which runs in a ring-shaped manner around the rotation axis R, wherein the spring element cap (13) with its annular projection (16) is in contact with the bearing inner ring (8) and the spring element (18) axially to the rotation axis R and / or is arranged between the bearing inner ring (8) and the spring element (18). [4] Side channel compressor (1) according to claim 1 or 2, characterized bythat the side channel compressor (1) has a contact disc (38), wherein the contact disc (38) is arranged in the direction of the rotation axis R between the spring element (18) and the inner wall (17) of the first housing part (3) and wherein the contact disc (38) is in contact with the spring element (18) and the inner wall (17). [5] Side channel compressor (1) according to one of the preceding claims, characterized by that the spring element (18) is designed as a corrugated spring (18). [6] Side channel compressor (1) according to claim 5, characterized by that the sleeve-shaped shoulder (14) has a height h running in the direction of the rotation axis R, wherein the height h runs in the direction of the rotation axis R and wherein the height h covers at least two turns of the corrugated spring (18). [7] Side channel compressor (1) according to claim 4, characterized bythat by means of the use of the contact disc (38) with a respective adjustable width dimension bn, a distance L between a first end face (37) of a stop disc (19) and the inner wall (17) of the first housing part (3) can be adjusted, wherein the stop disc (19) is located in the direction of the rotation axis R between the fastening element (28) and the bearing device (9), in particular a first rolling bearing (20a). [8] Side channel compressor (1) according to one of the preceding claims, characterized by that the bearing device (9) has two rolling bearings (20a, b) arranged next to one another along the rotation axis (R), wherein a spacer disc (15) is located between the rolling bearings (20a, b), wherein in particular the bearing outer rings (11a, b) are in contact with the spacer disc (15) axially to the rotation axis R. [9] Fuel cell system (2), comprising a fuel cell (21) with an oxygen inlet (22), a hydrogen inlet (23), an exhaust gas outlet (24), an anode (25), a cathode (26) and an electrolyte (27), characterized by that the fuel cell system (2) has a side channel compressor (1) according to one of the preceding claims, which is fluidly coupled to the exhaust gas outlet (24).

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