Side-channel compressor for a fuel cell system for conveying and / or compressing a gaseous medium, and fuel cell system

Abstract

The invention relates to a side-channel compressor (1) for a fuel cell system (2) for compressing a gaseous medium, the side-channel compressor comprising a housing having a first housing part (3) and a second housing part (4), wherein the first housing part (3) has a bearing journal (5) which extends along a rotational axis (R) and has a journal root portion (6) and a journal main portion (7), wherein a bearing inner ring (8) of a bearing device (9) is arranged on the journal main portion (7), wherein the bearing device (9) has a first bearing (19) and a second bearing (20), wherein a compressor wheel assembly (10) is arranged on a bearing outer ring (11) of the bearing device (9) so as to be rotatable about the rotational axis (R). According to the invention, the compressor wheel assembly (10) has, on its end face facing the second housing part (4), in particular on a first end face (30), a further lid-shaped sealing element (13) which at least almost completely covers the bearings (19, 20) and / or the bearing device (9) orthogonally to the rotational axis (R), wherein the lid-shaped sealing element (13) is at least indirectly connected to the hub (16) such that it is possible to fluidically encapsulate the interior (27) of the hub (16) with respect to the surroundings (29) of the compressor wheel assembly (10). The invention also relates to a fuel cell system (2) comprising a side-channel compressor (1) according to the invention.

Description

[0001] Description

[0002] title

[0003] Side channel blower for a to

[0004] The present invention relates to a side channel compressor for a fuel cell system for conveying and / or compressing a gaseous medium, in particular hydrogen, which is intended in particular for use in vehicles with a fuel cell drive. Furthermore, the invention relates to a fuel cell system with a device according to the invention.

[0005] In the future, gaseous fuels will play an increasingly important role in the automotive sector alongside liquid fuels. Hydrogen gas flows must be controlled, particularly in fuel cell-powered vehicles. The gas flows are no longer controlled discontinuously, as with liquid fuel injection; instead, the gaseous medium is taken from at least one high-pressure tank and fed to an ejector unit via an inlet line of a medium-pressure line system. This ejector unit feeds the gaseous medium to a fuel cell via a connecting line of a low-pressure line system. After the gaseous medium has flowed through the fuel cell, it is fed back to the ejector unit via a return line. A side channel compressor can be interposed to assist the gas recirculation in terms of flow and efficiency.Side channel compressors are also used to support flow buildup in fuel cell propulsion, particularly during a (cold) start of the vehicle after a certain period of inactivity. These side channel compressors are typically powered by electric motors, which are supplied with power from the vehicle battery during operation in vehicles.

[0006] DE 10 2022 203 058 A1 discloses a side channel compressor for a fuel cell system, in which a gaseous medium, in particular hydrogen, is conveyed and / or compressed, comprising a housing and a drive, wherein the housing has an upper housing part and a lower housing part, with a compressor chamber running in the housing circumferentially about a rotational axis and having at least one circumferential side channel. Furthermore, the side channel compressor has a compressor wheel located in a housing, which is arranged so as to be rotatable about the rotational axis and is driven by the drive, wherein the compressor wheel has blades arranged on its circumference in the region of the compressor chamber and each having a gas inlet opening and a gas outlet opening formed on the housing, which are fluidically connected to one another via the compressor chamber, in particular the at least one side channel.The side channel compressor comprises at least one bearing. According to the invention, each bearing comprises at least one sealing disc, which has a plurality of flow wedges extending at least approximately orthogonally to the rotational axis on its end face, in particular the face facing away from the bearing interior. A flow opening is formed between each two flow wedges, which extends at least approximately orthogonally to the rotational axis.

[0007] The side channel compressor known from DE 10 2022 203 058 A1 can have certain disadvantages. The side channel compressor known from DE 10 2022 203 058 A1 has sealing discs located between a bearing inner ring and a bearing outer ring in order to encapsulate the bearing interior. The sealing discs can, for example, have a plastic sealing lip on the bearing inner ring or on the bearing outer ring, which at least partially encapsulates the bearing interior by means of a sliding contact. This exemplary embodiment of the side channel compressor shown in the prior art has the disadvantage that the frictional contact leads to an increased temperature development in the area of ​​the sliding contact, which damages the at least one bearing and / or other components of the side channel compressor.In addition, especially at high speeds of the side channel compressor, material breakouts on the sealing lip and / or the respective bearing ring can occur, which can damage the side channel compressor and / or other components of the fuel cell system, such as a stack.

[0008] Furthermore, this exemplary embodiment of the side channel compressor shown in DE 10 2022 203 058 A1 has the disadvantage that the encapsulating effect diminishes over the service life of the side channel compressor due to material wear, meaning the bearing interior is no longer sealed from the environment. This can lead to the leakage of bearing grease, which increases wear on the respective bearing and thus the probability of failure. Furthermore, if the encapsulation of the bearing interior fails, water and / or hydrogen from the compressor chamber and / or from the fuel gas-carrying components of the fuel cell can penetrate through the sealing discs into the respective bearing and damage the metallic components.In addition, water penetration can cause the bearing grease inside the bearing to mix with the water, reducing lubrication performance and increasing the probability of failure of the bearing and the entire side channel compressor due to increased (frictional) wear. Hydrogen penetration can lead to hydrogen embrittlement, particularly of the rolling element, which reduces the service life of the bearing and the side channel compressor. Furthermore, the probability of failure of the bearing and the side channel compressor is increased, and the service life of the bearing and the side channel compressor is reduced.

[0009] 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 10. 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 with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[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 with a journal root section and a journal main section. A bearing inner ring of a bearing device is arranged on the journal main section. The bearing device comprises a first bearing and a second bearing, each bearing having two sealing disks that fluidically encapsulate the bearing interior. 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.wherein the first housing part is clamped at least indirectly to the bearing device via a fastening element. Furthermore, a spring element is arranged in the region of the pin root section in the direction of the rotation axis R at least indirectly between the bearing device and the first housing part,

[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 has further housing parts, which can be designed in particular 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 by the interaction of the first housing part with the second housing part.

[0013] The working chamber is preferably designed to be fluid-tight, apart from a working chamber inlet and a working chamber outlet. In the context of the invention, fluid-tight is also understood to mean that the tightness is maintained at a working pressure of the silk channel compressor that is higher than an ambient pressure. To ensure tightness, 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. The bearing journal is designed as a partial region of the first housing part and extends away 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] With reference to claim 1, the side channel compressor is designed such that the compressor wheel assembly has, on its end face facing the second housing part, in particular a first end face, a further cover-shaped sealing element which at least almost completely covers the bearings and / or the bearing device orthogonal to the axis of rotation R, so that the cover-shaped sealing element is at least indirectly connected to a hub in such a way that a fluidic encapsulation of the interior of the hub with respect to an environment of the compressor wheel assembly can be achieved.In this way, the advantage can be achieved that, on the one hand, the respective bearing and its bearing interior are additionally encapsulated against elements from the environment of the compressor wheel assembly by the cover-shaped sealing element, even if the respective sealing disc of the respective bearing fails over its service life due to frictional wear, in particular due to frictional wear of a sealing lip and / or sealing edge, and the bearing interior can therefore no longer be effectively encapsulated from the environment by means of the respective sealing disc. Due to the cover-shaped sealing element, an additional encapsulating barrier is present, which prevents water and / or hydrogen from penetrating the area of ​​a respective inner diameter of the hub and thus the bearing interior of the respective bearing and causing damage.Such damage would, for example, result from the bearing grease in the bearing interior mixing with the penetrating water, which would reduce the lubricating performance and increase the probability of failure of the respective bearing and the entire side channel compressor due to increased (frictional) wear. Such damage would, for example, result from hydrogen penetrating the bearing interior, leading to hydrogen embrittlement, in particular of the rolling element and / or the running surfaces of the bearing inner ring and / or the bearing outer ring, which would lead to failure of the respective bearing and to a reduced service life of the side channel compressor. Furthermore, the probability of failure of the respective bearing and the side channel compressor is increased and the service life of the respective bearing and the side channel compressor is reduced.Thus, by means of the inventive design of the side channel compressor according to claim 1, the probability of failure of the bearings can be prevented, whereby the service life of the entire side channel compressor can be increased.

[0018] The measures listed in the subclaims enable advantageous refinements of the side channel compressor specified in claim 1. The subclaims relate to preferred refinements of the invention. According to an advantageous embodiment of the side channel compressor, the hub has at least one bearing device region and a cover receiving region in the direction of the rotation axis R in the region of a first inner diameter, wherein the cover-shaped sealing element is arranged in the cover receiving region of the hub. This provides the advantage of simplified assembly of the cover-shaped sealing element in the hub. Thus, assembly costs can be reduced.Furthermore, the cover-shaped sealing element can be arranged in and / or on the hub in a space-saving manner, resulting in a compact design of the compressor wheel assembly, thereby reducing the size of the entire side channel compressor. This, in turn, can reduce the required installation space for the side channel compressor in the overall vehicle. Furthermore, efficient encapsulation of the bearing interior and the internal area in the hub can be achieved, as these areas can also be encapsulated to prevent water from entering the hub on the side of the compressor wheel assembly facing the drive. In this way, the likelihood of damage to the cover-shaped sealing element during assembly can be reduced, thereby reducing the probability of failure of the entire side channel compressor.

[0019] According to an advantageous development of the side channel compressor, the hub has a cover-disk receiving area in the direction of the rotation axis in the region of a second diameter, wherein a cover disc is arranged in the cover-disk receiving area, wherein the cover disc enables fluidic encapsulation of the interior of the hub from the surroundings of the compressor wheel assembly. This provides the advantage of encapsulating the respective bearing interior and / or the internal area in the hub, since these areas can also be encapsulated from the water penetration path on the side of the compressor wheel assembly opposite the drive.This prevents water from penetrating the bearing interior via the penetration path on the side opposite the drive, which could, for example, lead to mixing of the bearing grease in the bearing interior with the penetrating water. This would reduce lubricating performance and increase the probability of failure of the respective bearing and the entire side channel compressor due to increased (frictional) wear. Such damage would, for example, lead to hydrogen embrittlement, particularly of the rolling element and / or the running surfaces of the bearing inner ring and / or the bearing outer ring, which would cause the respective bearing to fail and reduce the service life of the side channel compressor.Thus, by means of the inventive design of the side channel compressor, in particular with the cover disc arranged in the cover disc receiving area, the probability of failure of the bearings can be prevented, whereby the service life of the entire side channel compressor can be increased.

[0020] According to a particularly advantageous embodiment of the side channel compressor, an O-ring is arranged orthogonally to the axis of rotation R between the cover-shaped sealing element and the first inner diameter of the hub, wherein the O-ring runs annularly around the axis of rotation R. Furthermore, the cover-shaped sealing element can be connected to the first diameter region of the hub, in particular in the cover-receiving region of the hub, by means of an interference fit and / or pressed into it, and the inner diameter of the hub is possible. In this way, the advantage of improved and efficient encapsulation of the bearing interior and the inner region in the hub can be achieved, since these regions can also be better encapsulated against the water penetration path on the side of the compressor wheel assembly facing the drive.The O-ring prevents water from penetrating between the outer diameter of the cover-shaped sealing element and the first inner diameter of the hub to the bearing and / or the bearing interior by enabling improved encapsulation. Due to its elasticity, the O-ring can adhere better to the surfaces of the hub and the cover-shaped sealing element, thus increasing the encapsulation effect. This can reduce the probability of failure of the respective bearing and thus of the entire side channel compressor.

[0021] In a particularly preferred embodiment of the invention, the cover-shaped sealing element is in contact with the bearing outer ring, in particular the first end face of the first bearing, at least in a partial area, in particular in the direction of the axis of rotation R. In this way, the advantage can be achieved that an improved and efficient encapsulation of the bearing interior and the inner area in the hub can be achieved, since these areas can also be better encapsulated compared to the water penetration path on the side of the compressor wheel assembly facing the drive. The O-ring prevents water from penetrating between the outer diameter of the cover-shaped sealing element and the first inner diameter of the hub to the bearing and / or bearing interior by enabling improved encapsulation.Due to its elasticity, the O-ring can adhere more effectively to the surfaces of the hub and the cover-shaped sealing element, thus increasing the encapsulation effect. This reduces the probability of failure of the respective bearing and thus of the entire side channel compressor.

[0022] According to a particularly advantageous embodiment of the side channel compressor, the lid-shaped sealing element comprises an elastic plastic, in particular PEEK (polyetheretherketone), and / or a stainless steel, and / or has at least partial elasticity. This provides the advantage of faster and more cost-effective assembly of the lid-shaped sealing element, since, due to the at least partial elastic deformability of the lid-shaped sealing element, it can be compressed and / or compressed prior to assembly in such a way that it is easy to move the lid-shaped sealing element in the direction of the rotational axis R into the hub, in particular the first inner diameter.The cover-shaped sealing element elastically returns to its previous shape in the final assembly position, thus achieving efficient encapsulation of the bearing interior and the inner area of ​​the hub. Due to its elasticity, the cover-shaped sealing element presses against the hub with a contact force, thus achieving an improved sealing and / or encapsulating effect. Due to the elasticity, an enlarged contact area is formed between the cover-shaped sealing element and the hub, thereby achieving improved encapsulation. This prevents damage to the bearing due to water and / or hydrogen penetrating the bearing interior.whereby the probability of bearing failure can be reduced and the service life of the entire side channel compressor can be increased. According to a particularly advantageous development of the side channel compressor, the cover disc runs in a ring-shaped manner around the rotational axis R, wherein the cover disc is in contact with a second end face of the bearing inner ring axially to the rotational axis R, and a third end face is in contact with the spring element and / or is arranged between the bearing inner ring and the spring element. In this way, the advantage of efficient encapsulation of the bearing interior can be achieved, since an additional fluidic barrier is created by the cover disc being in contact with the bearing inner ring. Furthermore, the use of the cover disc can be achieved in this way,which is located between the bearing inner ring and the spring element in the direction of the rotation axis R and is in contact with them, a direct contact point between the bearing inner ring and the spring element is prevented. In the event of a possible rotation of the bearing inner ring, there is no frictional contact with the spring element, which does not rotate. The cover plate is not rotating, and therefore there is no frictional contact between the spring element and the cover plate. This prevents wear on the spring element, although 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 compressor.

[0023] According to an advantageous development of the side channel compressor, the spring element is 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.

[0024] 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 the service life of the bearing device can be increased. Furthermore, the smooth running of the side channel compressor can be improved in this way.

[0025] The fuel cell system according to the invention provides all 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 side channel compressor in an overall vehicle in this way, in which the axis of rotation R of the compressor wheel assembly runs at an angle α to a reference axis, wherein the angle α lies in a range of 10° to 20°, in particular 15°, the advantage can be achieved that, by means of the cover-shaped sealing element and its corresponding positioning, water and / or hydrogen can be better drained away from the environment and / or a compressor chamber, so that the encapsulating effect of the bearing interiors can be achieved by means of the cover-shaped sealing element and / or the cover plate. Thus, by means of this inventive design of the fuel cell system, the service life of the side channel compressor and thus of the entire fuel cell system can be increased.

[0026] 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.

[0027] Short description of the drawing

[0028] The invention is described in more detail below with reference to the drawing.

[0029] It shows: Figure 1 in a sectional view a side channel compressor according to the state of the art,

[0030] Figure 2 shows a sectional view of a section of the side channel compressor designated II in Fig. 1 with a compressor wheel assembly according to the prior art,

[0031] Figure 3 shows a sectional view of a section of the side channel compressor according to the invention, designated II in Figure 1, with the compressor wheel assembly, which has a cover-shaped sealing element,

[0032] Figure 4 shows a plan view of a sectional view of the side channel compressor according to the invention according to its installation position in the vehicle.

[0033] Elements with the same function and mode of operation are provided with the same reference numerals in Figures 1 to 4.

[0034] 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, with in particular a respective bearing outer ring 11a, b being in contact with the spacer disk 15 axially to the rotation axis R. Bearing inner rings 8 of the bearing device 9 are arranged on the bearing journal 5. A hub 16 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 which runs circumferentially around the rotation axis R and has at least one circumferential side channel 35. As shown 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 12 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.

[0035] 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 four axial gaps 33a, b, c, d are located in the direction of the rotation axis R in the area between the compressor wheel assembly 10 and the respective housing part 3, 4, wherein the axial gaps 33a, b, c, d encapsulate the compressor chamber 36. The bearing journal 5 has a journal root section 6 directly adjacent to 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. The compressed gaseous medium can be conveyed from the compressor chamber 36 of the side channel compressor 1 to a fuel cell 26 of a fuel cell system 2.

[0036] In addition, Fig. 1 shows that a drive 37 is designed as an axial-field electric motor 37 having a stator 37, wherein by energizing the stator 37, a magnetic field is generated which acts on a segment magnet 44 (shown in Fig. 2) of the compressor wheel assembly 10 such that the compressor wheel assembly 10 is set in rotation. In an exemplary embodiment, the hub 16 can have a recess running annularly around the axis of rotation R, wherein the components return ring 46 and at least two segment magnets 44, ideally four segment magnets 44, are located at least almost entirely in the recess. In addition, a spacer sleeve 14 is shown, which is located in the direction of the axis of rotation R between the fastening element 28 and the bearing journal 5 and / or the respective bearing 19, 20.

[0037] Fig. 2 shows a sectional view of a section of the side channel compressor 1, designated II in Fig. 1, with at least one bearing 19, 20 and the spring element 18 according to the prior art. It is shown that the first bearing 19 has the bearing outer ring 11a and the bearing inner ring 8a, wherein the second bearing 20 has the bearing outer ring 11b and the bearing inner ring 8b. At least one respective sealing disk 21 is located between the respective bearing inner ring 8a, b and the respective bearing outer ring 11a, b in order to encapsulate a bearing interior 27, wherein in particular escape of a lubricant from the bearing interior 27 is prevented, but also contamination of the bearing interior 27 by particles from outside the respective bearing is prevented. The bearing inner ring 8b is at least indirectly in contact with the spring element 18 in the direction of the rotation axis R.The spring element 18 is supported at least indirectly on one side on an end face 40 (shown in Fig. 3) of the bearing inner ring 8b and on the other side on the inner wall 17 (shown in Fig. 3) 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, at least indirectly in the region 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 region 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 region. Increased wear may 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.

[0038] Furthermore, Fig. 2 shows that the hub 16 has at least one segment magnet 44 and at least one return ring 46 in the region of a recess running circumferentially around the rotation axis R. In addition, the compressor wheel 34 is mounted and fastened to the hub 16, for example by means of a screw connection. The bearing device 9 is screwed to the first housing part 3 by means of the fastening element 28, in particular a clamping bolt 28, by screwing the fastening element 28 into the journal 5. In addition, a contact disk 12 can be located 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. Furthermore, the contact disc 12 is in contact at least indirectly via a spacer sleeve 14 with a flat surface of the bearing journal 5 in the direction of the rotation axis R.By machining the spacer sleeve 14 prior to assembly, a bearing preload of the respective bearing 19, 20 can now be achieved, in particular by means of a bearing preload force 39. In this side channel compressor 1 according to the prior art, the bearing device 9 has a width B1 which runs in particular at least almost in the direction of the rotation axis R, wherein the width B1 corresponds at least almost to the width b31 of a first inner diameter 31 of the hub 16. The hub 16 also has a region of a second diameter 38 which has the width B3 in the direction of the rotation axis R. The total width of the hub 16 in the direction of the rotation axis R results from the width B1 and the width B3.

[0039] Fig. 2 further shows that, in an exemplary embodiment, the first bearing 19 and the second bearing 20 each have two sealing disks 21 which encapsulate the respective bearing 19, 20 with its bearing interior 27 against elements from an environment 29 and / or from the compressor chamber 36 of the side channel compressor 1. However, a respective sealing disk 21 of the respective bearing 19, 20 can fail over its service life due to frictional wear, in particular due to frictional wear of a sealing lip and / or sealing edge, and the bearing interior 27 is thus no longer effectively encapsulated against the environment 29 and / or the compressor chamber 36, so that water and / or hydrogen can penetrate into the respective bearing 19, 20 via an ingress path 43 and can damage the respective bearing 19, 20.

[0040] Fig. 3 shows a sectional view of a section of the side channel compressor 1 according to the invention, designated II in Fig. 1, with the compressor wheel assembly 10, which has a cover-shaped sealing element 13. The compressor wheel assembly 10 has the bearing device 9, which is arranged in the hub 16. The bearing device 9 has at least the first bearing 19, the second bearing 20 and the spacer disk 15, wherein the spacer disk 15 is arranged between the bearing outer rings 11 a, b in the direction of the rotation axis R and / or is in contact. The hub 16 has the region of the first inner diameter 31 and the second inner diameter 38, wherein the second inner diameter 38 lies in the region of a shoulder of the hub 16, wherein the shoulder serves as a stop, in particular an assembly stop, of the respective bearing outer ring 11 a, b.Furthermore, it is shown that the cover-shaped sealing element 13 runs at least almost rotationally symmetrically around the axis of rotation R and encloses the head of the fastening element 28, in particular of the clamping bolt 28, with a pot-shaped recess. With its annular end face facing away from the axis of rotation R and encircling the axis of rotation R, the cover-shaped sealing element 13 bears against the hub 16. Furthermore, the hub 16 has, in the region of the first inner diameter 31, at least one bearing device region 22 and a cover receiving region 24, which run at least almost in the direction of the axis of rotation R, wherein the cover receiving region 24 runs in the region of the first inner diameter 31 of the hub 16 on the side of the hub 16 facing the second housing part 4. The cover-shaped sealing element 13 is arranged in the cover receiving region 24 of the hub 16.

[0041] In this case, the cover-shaped sealing element 13 bears against the compressor wheel assembly 10 and / or the first bearing 19 on its end face facing the second housing part 4, in particular a first end face 30, in the direction of the rotational axis R. Furthermore, the cover-shaped sealing element 13 at least almost completely covers the bearings 19, 20 and / or the bearing device 9 orthogonally to the rotational axis R, so that the cover-shaped sealing element 13 is at least indirectly connected to the hub 16 in such a way that fluidic encapsulation of the interior 27 of the bearings 19, 20 and an interior of the hub 16 from the surroundings 29 of the compressor wheel assembly 10 can be achieved.

[0042] Furthermore, Fig. 3 shows that the hub 16 of the side channel compressor 1 according to the invention has a cover disk receiving area 25 in the direction of the rotation axis R in the region of the second diameter 38. A cover disk 23 is arranged in the cover disk receiving area 25, wherein by means of the cover disk 23, a fluidic encapsulation of the interior 27 of the bearings 19, 20 and the interior of the hub 16 from the surroundings 29 of the compressor wheel assembly 10 can be achieved. In an exemplary embodiment of the side channel compressor 1 and / or the compressor wheel assembly 10, an O-ring 41 can be arranged orthogonal to the rotation axis R between the cover-shaped sealing element 13 and the first inner diameter 31 of the hub 16, wherein the O-ring 41 runs annularly circumferentially around the rotation axis R.Furthermore, it is shown that the cover-shaped sealing element 13 is in contact with the bearing outer ring 11a, in particular the first end face 30 of the first bearing 19, at least in a partial area, in particular in the direction of the rotation axis R. By means of the inserted O-ring 41 and the contact of the sealing element 13 with the respective bearing outer ring 11a, b, a better encapsulation of the compressor wheel assembly 10 and / or the bearings 19, 20 and / or the respective bearing interior 27 can be achieved. The hub 16 thus has, on the one hand, in the area of ​​the first inner diameter 31, the cover receiving area 24 with the width B2 and the bearing device area 22 with the width B1. On the other hand, the hub 16 has, in the area of ​​the second inner diameter 38, the cover disk receiving area 25 with the width B3. The widths B1, B2 and B3 together form the total width of the hub 16 in the direction of the rotation axis R.

[0043] The cover-shaped sealing element 13 shown in Fig. 3 can, in an exemplary embodiment of the side channel compressor 1, comprise an elastic plastic, in particular PEEK (polyetheretherketone). Thus, the sealing element has a certain elasticity, which leads to simplified assembly and improved encapsulating properties. This reduces the probability of failure of the respective bearings 19, 20, in particular due to water and / or hydrogen penetrating from the environment 29 into the bearing interior 27. For further improved encapsulation of the respective bearing interiors, the cover disk 23 extends in a ring-shaped manner around the rotation axis R. The cover disk 23, axially relative to the rotation axis R, firstly bears against a second end face 32 of the bearing inner ring 8, and secondly bears against the spring element 18 with a third end face 40 and / or is arranged between the bearing inner ring 8 and the spring element 18.The spring element 18 can be designed as a wave spring 18. Furthermore, Fig. 3 shows that the side channel compressor 1, in an exemplary embodiment, with its bearing device 9, has two rolling bearings 19, 20 arranged next to one another along the axis of rotation R, wherein the spacer disk 15 is located between the rolling bearings 19, 20, wherein in particular the bearing outer rings 11 a, b are in contact with the spacer disk 15 axially to the axis of rotation R. Furthermore, Fig. 3 shows that by using the contact disk 12 with a respective adjustable width dimension, the preload force 39 of the bearings 19, 20 can be adjusted, wherein the contact disk 12 is located in the direction of the axis of rotation R between the fastening element 28 and the bearing device 9, in particular a first rolling bearing 19, 20. The spring element 18 presses the compressor wheel assembly 10 up to the contact disc 12.In this case, the compressor wheel 34 is adjusted to the first housing part 3 and to the second housing part 4 and stator housing in such a way that the respective axial gaps 33 a, b, c, d (shown in Fig. 1) have at least approximately the same size and are within the tolerances so that a collision between the compressor wheel 34 and the respective housing part 3, 4 is avoided and the gap size is not so large that encapsulation of the compressor chamber 36 can be ensured due to excessively large gap sizes.

[0044] Fig. 4 shows a fuel cell system 2 in a top view sectional view of a side channel compressor 1 according to its installation position in the vehicle according to the invention. A horizontal reference axis 45, a direction of action 47 of gravity, and the axis of rotation R of the side channel compressor 1 are shown. As shown, the side channel compressor 1 is installed in an overall vehicle such that the axis of rotation R of the compressor wheel assembly 10 runs at an angle α to the horizontal reference axis 45, wherein the angle α lies in a range of 10° to 20°, in particular 15°. The direction of action 47 of gravity runs at an at least almost right angle, in particular 90°, to the horizontal reference axis 45. This installation position makes it possible to achieve improved encapsulation of the bearing interior 27 by allowing the water to drain away more effectively and be better encapsulated by the cover-shaped sealing element 13.

Claims

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 the bearing device (9) has a first bearing (19) and a second bearing (20), wherein each bearing (19, 20) has two sealing disks (21) which encapsulate the bearing channel space (27), 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) and is driven by a drive (37). can be driven,wherein 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 in the journal root section (6) in the direction of the rotational axis (R) at least indirectly between the bearing device (9) and the first housing part (3), characterized in that the compressor wheel assembly (10) has, on its end face facing the second housing part (4), in particular a first end face (30), a cover-shaped sealing element (13) which at least almost completely covers the bearings (19, 20) and / or the bearing device (9) orthogonal to the rotational axis (R), wherein the cover-shaped sealing element (13) is at least indirectly connected to the hub (16) in such a way that a fluidic encapsulation of the interior (27) of the hub (16) with respect to an environment (29) of the compressor wheel assembly (10) can be achieved.

2. Side channel compressor (1) according to claim 1, characterized in that the hub (16) in the direction of the rotation axis (R) in the region of a first inner diameter (31) has at least one bearing device region (22) and a cover receiving region (24), wherein the cover-shaped sealing element (13) is arranged in the cover receiving region (24) of the hub (16).

3. Side channel compressor (1) according to claim 1 or 2, characterized in that the hub (16) has a cover disc receiving area (25) in the direction of the axis of rotation (R) in the region of a second diameter (38), wherein a cover disc (23) is arranged in the cover disc receiving area (25), wherein by means of the cover disc (23) a fluidic encapsulation of the interior (27) of the hub (16) with respect to the surroundings (29) of the compressor wheel assembly (10) can be achieved.

4. Side channel compressor (1) according to one of the preceding claims, characterized in that an O-ring (41) is arranged orthogonally to the axis of rotation R between the cover-shaped sealing element (13) and the first inner diameter (31) of the hub (16), wherein the O-ring (41) runs annularly around the axis of rotation (R).

5. Side channel compressor (1) according to one of the preceding claims, characterized in that the cover-shaped sealing element (13) is in contact with the bearing outer ring (11 a), in particular the first end face (30) of the first bearing (19), at least in a partial area, in particular in the direction of the axis of rotation (R).

6. Side channel compressor (1) according to one of the preceding claims, characterized in that the cover-shaped sealing element (13) comprises an elastic plastic, in particular PEEK (polyetheretherketone), and / or a stainless steel and / or has at least partially existing elasticity.

7. Side channel compressor (1) according to claim 3, characterized in that the cover disc (23) runs in a ring-shaped manner around the rotational axis R, wherein the cover disc (23) axially to the rotational axis R on the one hand with a second end face (32) of the bearing inner ring (8) in contact and on the other hand, with a third end face (40) is in contact with the spring element (18) and / or is arranged between the bearing inner ring (8) and the spring element (18).

8. Side channel compressor (1) according to one of the preceding claims, characterized in that the spring element (18) is designed as a corrugated spring (18) 9. Side channel compressor (1) according to one of the preceding claims, characterized in that the bearing device (9) has two rolling bearings (19, 20) arranged next to one another along the axis of rotation (R), a spacer disk (15) being located between the rolling bearings (19, 20), the bearing outer rings (11 a, b) in particular being in contact with the spacer disk (15) axially to the axis of rotation R.

10. Fuel cell system (2), comprising a fuel cell (26) and / or a side channel compressor (1), characterized in that the side channel compressor (1) is installed in an overall vehicle in such a way that the axis of rotation (R) of the compressor wheel assembly (10) runs at an angle (α) to a reference axis (45), wherein the angle (α) is in a range of 10° to 20°, in particular 15°.

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