COMPRESSOR HAVING A SEALING CHANNEL

Abstract

A compressor having a housing and a rotor, the rotor having a compressor impeller at least on one side; a compressor chamber being configured between the compressor impeller and the housing; the rotor being rotationally mounted; an annular sealing channel being configured between the rotor and the housing; the sealing channel being routed from the compressor chamber to a lower-pressure zone; at least two throttling sections being provided in the sealing channel; in each of the two throttling sections, in the direction of flow viewed from the compressor chamber to the lower-pressure zone, a first section having a reduction in the cross section of the sealing channel being first provided, and a second section having an enlargement of the cross section of the sealing channel being subsequently provided.

Claims

1-14. (canceled)

15. A compressor, comprising: a housing; a rotor having a compressor impeller at least on one side, the rotor being rotationally mounted; a compressor chamber configured between the compressor impeller and the housing; and an annular sealing channel configured between the rotor and the housing, the sealing channel being routed from the compressor chamber to a lower-pressure zone, at least two throttling sections being provided in the sealing channel, in each of the two throttling sections, in the direction of flow viewed from the compressor chamber to the lower-pressure zone, a first section having a reduction in the cross section of the sealing channel being first provided, and a second section having an enlarged cross section of the sealing channel being subsequently provided.

16. The compressor as recited in claim 15, wherein two contours are provided between the rotor and the housing in the sealing channel, wherein, viewed in a plane of an axis of rotation of the rotor, the contours having steps, the steps of the contours being formed in such a way that the two throttling sections are realized by the steps of the contours.

17. The compressor as recited in claim 16, wherein the contours are in the form of ascending and descending stairs.

18. The compressor as recited in claim 16, wherein the contours are in the form of at least a radial web and at least a radial recess, the web engaging into the recess.

19. The compressor as recited in claim 18, wherein the recess is bounded by side walls of different heights, as viewed axially, and wherein the web has side walls of different heights, as viewed radially.

20. The compressor as recited in claim 15, wherein the first portion of the throttling section is formed by a constriction that is disposed radially relative to an axis of rotation of the rotor and between the rotor and the housing, and the second portion of the throttling section is realized by an axial distance that, viewed in the axial direction, is disposed parallel to the axis of rotation of the rotor and between the rotor and the housing.

21. The compressor as recited in claim 15, wherein at least three or more throttling sections are provided in the sealing channel, as viewed in the flow direction.

22. The compressor as recited in claim 18, wherein the web, extending from the housing or the rotor, has a first section that merges into a second section, wherein viewed in a plane of an axis of rotation of the rotor, the first section has a smaller width than the second section.

23. The compressor as recited in claim 22, wherein the second section has an annular first surface that is disposed radially at the end face and that is associated with an annular second surface, which is disposed radially at the end face, of a recess in the form of a radial groove, wherein the first and second surface are oriented mutually in parallel.

24. The compressor as recited in claim 15, wherein the compressor impeller is configured on a first side of the rotor, a further compressor impeller is configured on a second side of the rotor opposite the first side, the further compressor impeller constituting a high pressure stage, and the compressor impeller constituting a low-pressure stage, the further compressor impeller being positioned in a further compressor chamber of the housing, and the sealing channel being formed between the compressor chamber and the further compressor chamber thereof.

25. The compressor as recited in claim 15, wherein the rotor is rotationally mounted on the housing via a contactless bearing, and the sealing channel is configured in the area of the bearing.

26. The compressor as recited in claim 15, wherein a sealing element is configured on at least one of the rotor and the housing, the sealing element being formed of a softer material than the rotor or the housing, and the sealing element constitutes at least one side of at least one throttling section.

27. The compressor as recited in claim 26, wherein the sealing element is configured on the housing, a radial recess is configured in the sealing element, and a radial web, which engages into the recess, is formed on the rotor.

28. The compressor as recited in claim 15, wherein the compressor is a turbocompressor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows a first specific embodiment of a compressor having a rotor including a compressor impeller on one side.

[0024] FIG. 2 shows a second specific embodiment of a compressor having a rotor including two compressor impellers.

[0025] FIG. 3 shows a specific embodiment of a rotor that is supported on a shaft.

[0026] FIG. 4 shows a specific embodiment of a compressor; a sealing element being configured on the rotor.

[0027] FIG. 5 shows a specific embodiment of a compressor; a sealing element being configured on the housing.

[0028] FIG. 6 through 10 show various specific embodiments of contours between the housing and the rotor.

[0029] FIG. 11 through 14 show various specific embodiments of contours in the form of a web and a recess for realizing the sealing channel.

[0030] FIG. 15 shows another specific embodiment of a compressor.

[0031] FIG. 16 shows another specific embodiment of a compressor.

[0032] FIG. 17 shows an additional specific embodiment of a compressor.

[0033] FIG. 18 shows an enlarged representation of the sealing channel of the specific embodiment of FIG. 17.

[0034] FIG. 19 shows another specific embodiment of a compressor.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0035] FIG. 1 shows a schematic cross section through a part of a compressor 1 that has a housing 2 and a rotor 3. Rotor 3 is designed to be axially symmetric to an axis of rotation 4. On a first side, rotor 3 has a first compressor impeller 5 having rotor blades. A first compressor chamber 6 is configured between first compressor impeller 5 and housing 2. In the illustrated exemplary embodiment, first compressor chamber 6 has an annular first intake duct 7. In response to rotation of rotor 3 about axis of rotation 4, a medium is drawn in via first intake duct 7, compressed by first compressor impeller 5, and output via a first compression channel 8. A sealing channel 11, which allows first compressor chamber 6 to communicate with a zone having a lower pressure 12, is configured between a radial exterior 9 of rotor 3 and an associated interior 10 of housing 2.

[0036] Rotor 3 may be rotationally mounted in the region of sealing channel 11, for example, via a contactless bearing in housing 2. Depending on the specific embodiment selected, rotor 3 may also be connected to a shaft (not shown) that is located in axis of rotation 4 and is rotationally mounted on housing 2.

[0037] FIG. 2 shows a specific embodiment of a compressor 1 that is fabricated in accordance with the compressor of FIG. 1; on a second side, however, rotor 3 having a second compressor impeller 13 having second rotor blades. In addition, a second compressor chamber 14 is configured between second compressor impeller 13 and housing 2. Furthermore, second compressor chamber 14 has a second intake duct 15. In addition, a second compression channel 16 is provided in housing 2. Second compressor impeller 13 is designed to be axially symmetric to axis of rotation 4. Second compressor chamber 14 communicates via sealing channel 11 with first compressor chamber 6. In addition, second intake duct 15 may communicate with first compressor channel 8 via a line that is schematically indicated by an arrow. This makes it possible for two compressor stages to be realized in a compressor 1 with the aid of a rotor 3. First compressor impeller 5 pre-compresses the medium; a second, higher compression of the pre-compressed medium, that is subsequently output via second compression channel 16, being achieved by second compressor impeller 13.

[0038] In a schematic representation, FIG. 3 shows a specific embodiment of a compressor 1 in accordance with FIG. 2 having a rotor 3 having two compressor impellers 5, 13, that are located on opposite sides. In this specific embodiment, rotor 3 is rotationally mounted on housing 2 via a shaft 19. Analogously, the specific embodiment of FIG. 1 may also include a rotor 3 having only one first compressor impeller 5 that is mounted via a corresponding shaft 19 on housing 2.

[0039] In a schematic representation, FIG. 4 shows the variant of the compressor of FIG. 2; an annular sealing element 17, which engages into an annular recess 18 of housing 2, being provided on rotor 3 in the area of sealing channel 11. Sealing element 17 is made of a different material than rotor 3, for example. In particular, a softer material may be used to manufacture sealing element 17 in order to enhance the desired sealing function. Sealing element 17 may be made of a plastic material, for example. In the case of a compressor 1, sealing element 17 may also be provided with a rotor 3 having only one first compressor impeller 5 in accordance with the specific embodiment of FIG. 1.

[0040] FIG. 5 shows another specific embodiment of the compressor of FIG. 2, an annular sealing element 17 being configured on an inner side 10 of housing 2. Sealing element 17 engages into an annular second recess 18 of outer side 9 of rotor 3. Compressor 1 of FIG. 1 having a rotor 3 having only a first compressor impeller 5 may likewise feature a sealing element 17 and a recess 18 in accordance with FIG. 5.

[0041] FIG. 6 through 10 show various graduated contours 21, 22 of inner side 10 of housing 2 and of outer side 9 of rotor 3 that are associated with one another. Depending on the specific embodiment selected, every contour 21, 22 may be realized by rotor 3 or by housing 2. In addition, every contour 21, 22 maybe at least partially or completely realized by a sealing element 17 or have a sealing element 17 that is joined to housing 2, respectively to rotor 3.

[0042] FIG. 6 shows an enlarged, schematically illustrated detail view of sealing channel 11 that is configured between a first and a second contour 21, 22. FIG. 6 shows a cross section through a plane of axis of rotation 4. Both the first and the second contour are designed to be axially symmetric relative to axis of rotation 4. Axis of rotation 4 may be located below second contour 22, for example. In this specific embodiment, second contour 22 is constituted of rotor 3 or of a sealing element thereof. First contour 21 is constituted of inner side of housing 2 or at least partially of a sealing element thereof. Depending on the specific embodiment selected, axis of rotation 4 may also be located above first contour 21. Accordingly, first contour 21 is constituted of rotor 3 or at least partially of a sealing element thereof. Accordingly, second contour 22 is constituted of an inner side of housing 2 or at least partially of a sealing element of housing 2. These variants also hold for the following FIG. 7 through 10.

[0043] In cross section, first contour 21 features an annular web 24 in a flow direction 23 from a higher-pressure zone toward a lower-pressure zone. The higher-pressure zone may be constituted of first compressor chamber 6 in the case of a rotor 3 having only one first compressor impeller 5 or of second compressor chamber 14 in the case of a rotor 3 having a first and a second compressor impeller 5, 13. Web 24 has the same radial height on both sides. Second contour 22 has a radial recess in the form of a groove 28. Groove 28 is designed to be wider than web 24 in the axial direction, i.e., parallel to axis of rotation 4. Moreover, web 24 projects radially into groove 28.

[0044] In flow direction 23, viewed axially, first contour 21 has a first annular surface 31, a second annular surface 32, and a third annular surface 33. First and third annular surface 31, 33 are configured at the same radial distance to axis of rotation 4. Second annular surface 32 bounds web 24; second annular surface 32 having a greater or smaller distance to axis of rotation 4 than first or third annular surface 31, 33, depending on the location of axis of rotation 4.

[0045] In flow direction 23, viewed axially, second contour 22 has another first, second and third annular surface 41, 42, 43. First and second further annular surface 41, 42 are configured at the same radial distance to axis of rotation 4. Second further annular surface 42 bounds groove 28; second further annular surface 42 having a greater or smaller distance to axis of rotation 4 than further first or third annular surface 41, 43, depending on the location of axis of rotation 4.

[0046] Web 24 has a first axial annular surface 35 and an opposite, second axial annular surface 36; relative to flow direction 23, first, axial annular surface 35 being configured upstream from second, axial annular surface 36. Groove 28 is bounded by a first and a second axial annular surface 45, 46. Relative to flow direction 23, first, axial annular surface 45 is configured upstream from second, axial annular surface 46.

[0047] Contours 21, 22 may be subdivided axially into five sections 51, 52, 53, 54, 55. First section 51 extends in flow direction 23 to further first axial annular surface 45. Second section 52 extends axially from axial annular surface 45 to first axial annular surface 35. Third section 53 extends from first, axial annular surface 35 to second, axial annular surface 36. Fourth section 54 extends from second, axial annular surface 36 to further, second axial annular surface 46. Fifth section 55 extends from further, second axial annular surface 46 to the end of first and second contour 21, 22.

[0048] In first, third and fifth sections 51, 53, 55, radial distances 71, 72, 73 between the contours are crucial to influencing the flow in sealing channel 11. In second and fourth section 52, 54, axial distances 81, 82 between the side surfaces of the contours are important for influencing the flow.

[0049] The radial distances between contours 21, 22 in first, third and fifth section 51, 53, 55, and the axial distances between contours 21, 22 in second and in fourth section 52, 52 may be appropriately selected as a function of the selected specific embodiment, in order to provide at least two, preferably three throttling sections. For example, radial distances 71, 72, 73 of first, third and fifth section between contours 21, 22 may be selected to be smaller than axial distances 81, 82 between contours 21, 22 in second and fourth section 52, 54. Depending on the specific embodiment selected, axial and radial distances 71, 72, 73, 81, 82 between contours 21, 22 may be variably defined in order to realize the desired throttling sections. Tests have shown that a cost effective manufacturing of at least the same quality is achieved for the sealing of the sealing channel when radial distances 71, 72, 73 in first, third and fifth section 51, 53, 55 between the surfaces of contours 21, 22 are selected to be smaller than axial distances 81, 82 in second and fourth section 52, 54 between contours 21, 22.

[0050] Axial and/or radial distances 71, 72, 73, 81, 82 may be within the range of between 10 and 500 μm or more. Moreover, the length of sealing channel 11 may be within the range of between 1 and 15 mm or more. In addition, the sections in FIG. 6 may be partitioned to allow web 24 to take up approximately one third of the length of the sealing channel, and the regions to the sides of web 24 each one third of sealing channel 11.

[0051] Tests have shown that effective results are obtained at a ratio of radial distance 71, 72, 73 in first, third and fifth section 51, 53, 55 to an axial distance 81, 82 in second and fourth section 52, 54 within the range of between 1:3 or more. For example, effective results are obtained at an axial distance 81, 82 in second and fourth section 52, 54 of 100 to 200 μm, and at a radial distance 71, 72, 73 in first, third and fifth section 51, 53, 55 of between 10 and 30 μm. The axial and radial distances in the sections may be selected to be different or of equal value. Tests have shown that effective results are obtained at radial and/or axial distances of equal value, respectively.

[0052] FIG. 7 shows another specific embodiment of sealing channel 11; viewed in flow direction 23, first contour 21 having a stepped contour having a decreasing thickness, and second contour 22 having a stepped contour having an increasing thickness. First and second contour 21, 22 are designed to be axially symmetric to axis of rotation 4. In flow direction 23, viewed axially, first contour 21 has a first annular surface 31, a second annular surface 32, and a third annular surface 33. First radial annular surface 31 merges via a first axial annular surface 35 into second radial annular surface 32. Second radial annular surface 32 merges via a second axial annular surface 36 into third radial annular surface 33. In the selected variant, axis of rotation 4 is located in the middle of second contour 22. Annular surfaces 31, 32, 33 are oriented parallel to axis of rotation 4. First annular surface 31 features a smaller distance to axis of rotation 4 than second annular surface 32. Third annular surface 33 features a larger distance to axis of rotation 4 than second annular surface 32. If axis of rotation 4 is located in the middle of first contour 21, the radial distance between the annular surfaces and axis of rotation 4 decreases by steps in flow direction 23.

[0053] In flow direction 23, viewed axially, second contour 22 has another first, second and third annular surface 41, 42, 43. Further first radial annular surface 41 merges via a further first axial annular surface 45 into further second radial annular surface 42. Further second radial annular surface 42 merges via a further second axial annular surface 46 into further third radial annular surface 43. Further first, second and third annular surfaces 41, 42, 43 each features an increasing radial distance from axis of rotation 4. If axis of rotation 4 is located in the middle of first contour 21, then the radial distance between the annular surfaces and axis of rotation 4 decreases by steps in flow direction 23.

[0054] In the illustrated specific embodiment, first axial annular surface 35 and further first radial annular surface 45 overlap radially in each particular case. Thus, an axial sealing gap having a first axial distance 81 is formed. Moreover, second, axial annular surface 36 and further, second radial annular surface 46 overlap radially. Thus, a second axial sealing gap having a second axial distance 82 is formed.

[0055] Contours 21, 22 may be subdivided axially into five sections 51, 52, 53, 54, 55. First section 51 extends in flow direction 23 to further first axial annular surface 45. Second section 52 extends axially from axial annular surface 45 to first axial annular surface 35. Third section 53 extends from first axial annular surface 35 to second axial annular surface 36. Fourth section 54 extends from second axial annular surface 36 to further, second axial annular surface 46. Fifth section 55 extends from further, second axial annular surface 46 to the end of first and second contours 21, 22. In first, third and fifth sections 51, 53, 55, radial distances 71, 72, 73 between the contours are crucial to the influencing of the flow. In second and fourth sections 52, 54, axial distances 81, 82 between the side surfaces of the contours are important for influencing the flow.

[0056] Radial distances 71, 72, 73 between contours 21, 22 in first, third and fifth sections 51, 53, 55, and axial distances 81, 82 between contours 21, 22 in second and fourth sections 52, 54 may be appropriately selected as a function of the selected specific embodiment, in order to provide at least two, preferably three throttling sections. For example, radial distances 71, 72, 73 of first, third and fifth sections between contours 21, 22 may be selected to be smaller than axial distances 81, 82 between contours 21, 22 in second and fourth sections 52, 54. Depending on the specific embodiment selected, axial and radial distances 71, 72, 73, 81, 82 between contours 21, 22 may be variably defined in order to realize the desired throttling sections.

[0057] FIG. 8 shows a specific embodiment of a compressor 1 that essentially corresponds to FIG. 6; however, first contour 21 being formed on rotor 3 and second contour 22 on housing 2. Axis of rotation 4 is located in the middle of second contour 22.

[0058] FIG. 9 shows another specific embodiment of a compressor 1 that is disposed mirror-symmetrically to the specific embodiment of FIG. 7 relative to flow direction 23.

[0059] FIG. 10 shows another specific embodiment that essentially corresponds to the specific embodiment of FIG. 5; however, first and third annular surfaces 31, 33 having different radial distances to axis of rotation 4. Analogously, further first annular surface 41 and further third annular surface 43 have different radial heights. In the illustrated specific embodiment, first axial annular surface 35 and further, first radial annular surface 45 overlap radially in each particular case. Thus, an axial sealing gap having a first axial distance 81 is formed. Moreover, second axial annular surface 36 and further second, radial annular surface 46 overlap radially. Thus, a second axial sealing gap having a second axial distance 82 is formed. Viewed radially, first axial sealing gap is longer than second axial sealing gap. Depending on the variant selected, the second axial sealing gap may also be configured to be longer. FIG. 11 through 14 show different specific embodiments of FIG. 5; the specific embodiments differing in the height of web 24, respectively in the depth of groove 28. In FIG. 11 through 13, radial distances 71, 72, 73 between first, second and third annular surface 31, 32, 33 and the associated further first, further second, and further third annular surface 41, 42, 43 are each equal. First axial annular surface 35 and further, first radial annular surface 45 overlap axially. Thus, an axial sealing gap having a first axial distance 81 is formed. Moreover, second axial annular surface 36 and further, second radial annular surface 46 overlap radially. Thus, a second, axial sealing gap having a second, axial distance 82 is formed.

[0060] Viewed radially, axial sealing gaps 91, 92 are longer relative to the axis of rotation in FIG. 11 than in FIG. 12. Viewed radially, axial sealing gaps are longer relative to the axis of rotation 4 in FIG. 12 than in FIG. 13; viewed radially, the sealing gaps in FIG. 13 being longer than in FIG. 11.

[0061] In FIG. 14, radial distances 71, 72, 73 between first, second and third annular surfaces 31, 32, 33 and the associated further first, further second, and further third annular surfaces 41, 42, 43 are smaller than in FIG. 11 through 13. Axial distances 81, 82 between the side walls of groove 28 and the side walls of web 24 may vary within the range of between 50 and 250 μm, for example. Radial distances 71, 72, 73 may vary within the range of between 10 and 100 μm, for example.

[0062] As a function of the selected specific embodiment, in FIG. 11 through 14, first contour 21 may be configured on the housing and second contour 22 on the rotor, or first contour 21 on the rotor and second contour 22 on the housing.

[0063] Moreover, depending on the specific embodiment selected, at least one portion of first or second contour 21, 22, i.e., one section of a contour, in particular web 24 may be configured in the form of a sealing element 17. Moreover, entire first and/or second contour 21, 22 may also be formed on a sealing element 17.

[0064] In a schematic part sectional view, FIG. 15 shows a portion of a compressor 1; housing 2 having a sealing element 17 that extends between compressor impellers 5, 13. On a front side, sealing element 17 has a circumferentially extending groove 28 and thus the form of second contour 22. Configured on rotor 3 is first contour 21 having web 24 that extends into groove 28 of second contour 22. Formed in this specific embodiment are further axial distances 83, 84 between compressor impellers 5, 13 and sealing element 17 within the range of between 50 and 250 μm, for example. Furthermore, radial distances 71, 72, 73 between first and second contour 21, 22 are configured in the region of first, third, and fifth section 51, 53, 55 within the range of between 10 and 30 μm. Moreover, axial distances 81, 82 are configured between first and second contour 21, 22 in the region of second and fourth section 52, 54 within the range of between 50 and 250 μm.

[0065] Moreover, viewed radially, the depth of groove 28 may be within the range of between 0.5 and 3 mm or more. Accordingly, the length of web 24 is adapted for attaining desired, second radial distance 72 in third section 53. Depending on the specific embodiment selected, first contour 21 may likewise be configured in the form of a sealing element or at least of a different material than the rotor and compressor impellers 5, 13 thereof. For example, first contour 21 may be fabricated of a separate component that is secured to rotor 3.

[0066] FIG. 16 shows another specific embodiment that essentially corresponds to the specific embodiment of FIG. 15; however, the depth of the recess being smaller on the inner side of sealing element 17. The axial and radial distances are retained. In particular, the depth of the recess may be within the range of 1 mm. Moreover, first contour 21 may be machined from the material of rotor 3, as shown in the illustrated example.

[0067] In a schematic representation, FIG. 17 shows a portion of a compressor 1 having a design similar to that of FIG. 15; however, first contour 21 being formed on housing 2 and second contour 22 on rotor 3. Moreover, first contour 21 has the distinctive feature that web 24 has a first web portion 61 that merges radially inwardly toward axis of rotation 4 into a second web portion 62. In the axial direction, the diameter of first web portion 61 is smaller than that of second web portion 62. Viewed in the axial direction of axis of rotation 4, the diameter of first web portion 61 may be half of that of second web portion 62, for example. Moreover, viewed in the axial direction of the axis of rotation, second web portion 62 has a smaller width than sealing element 17 that projects into the clearance space between compressor impellers 5, 13. Moreover, viewed in flow direction 23, sealing element 17 may have an annular recess 63 in fifth section 55 that provides for a one-sided flattening of sealing element 17. In place of sealing element 17, housing 2 may also feature first contour 21. Moreover, second contour 22 may also be at least partially realized by a sealing element 17.

[0068] In a schematic representation, FIG. 18 shows an enlarged representation of FIG. 17; in first section 51, there being a first small radial distance 71 between first and second contour 21, 22. The cross section subsequently widens in the area of second section 52 which is additionally enlarged by the thinner formation of first web portion 61. In third section 53, there is again a small, radial second distance 72 between contours 21, 22. An enlarged cross section is subsequently again provided by the small width of first web portion 61 in fourth section 54. In fifth section 55, the overlapping of the first and second contour is shortened axially in comparison to first section 51. This is accomplished, for example, in that sealing element 17 in this area has an annular recess 63 in the form of a chamfer. Thus, in a sixth section 56, a relatively large space for expanding the medium is provided in the area of chamfer 63. In spite of the small installation space, this specific embodiment achieves more space for expanding the medium downstream of the radial sealing gaps realized by radial distances 71, 72, 73.

[0069] The radial gap seals used are insensitive to axial deformations or forces. The specific embodiment of FIGS. 17 and 18 provides a substantial acceleration three times through sections 51, 53 and 55 and a corresponding subsequent deceleration of the leakage medium in sections 52, 53 and 56. The acceleration is achieved in radial sealing gaps that are located on the smallest possible radii. The subsequent deceleration is achieved by a deceleration of the flow cross section following the acceleration. The leakage medium is considerably accelerated in first section 51; a deceleration being achieved in second section 52. The leakage medium is accelerated, in turn, in third section 53, and is again decelerated in fourth section 54. Correspondingly, an acceleration takes place in fifth section 55, and, again, a deceleration in sixth section 56.

[0070] FIG. 19 shows another specific embodiment of a compressor 1 that essentially corresponds to the specific embodiment of FIG. 17; in contrast to FIG. 17, however, the compressor only having a first compressor impeller 5.

[0071] The shapes illustrated in the figures for the surfaces that bound sealing channel 11 are shown as contours that have an angular cross section. The angular contours may also be formed as rounded contours. In particular, convex and/or concave contours may, therefore, oppose one another to form sealing channel 11. In particular, groove 28 and/or web 24 may have rounded edges in cross section, so that a concave and a convex shape oppose one another in order to form sealing channel 11. In addition, recess 18 and/or sealing element 17 may have rounded edges in cross section, so that a concave and a convex shape oppose one another in order to form sealing channel 11. Similarly, the stepped structures of FIGS. 7 and 8 may likewise have rounded corners in cross section. Here as well then, concave and convex surfaces, which bound sealing channel 11, oppose one another.

[0072] Moreover, the surfaces in the figures that bound sealing channel 11 in the radial direction and are illustrated parallel to axis of rotation 4, i.e., first and/or second and/or third annular surface 31, 32, 33 may also be oriented to not be parallel to axis of rotation 4. In particular, first and/or second and/or third annular surface 31, 32, 33 may be oriented obliquely to axis of rotation 4 at different angles. Moreover, further first and/or further second and/or further third annular surface 41, 42, 43, which are shown parallel to the axis of rotation in the figures, may also be oriented to not be parallel to axis of rotation 4. In particular, further first and/or further second and/or further third annular surface 41, 42, 43 may be oriented at different rotational angles to axis of rotation 4.

[0073] Furthermore, the surfaces of the figures that bound sealing channel 11 in the axial direction and are shown in the figures orthogonally to the axis of rotation, may also be configured to not be orthogonal to axis of rotation 4. For example, the surfaces may be oriented at different angles to axis of rotation 4. In particular, first and/or second axial annular surface 35, 36 may be oriented at angles not equal to 90° to axis of rotation 4. Further first and/or further second axial annular surface 45, 46 may also be oriented at angles not equal to 90° to axis of rotation 4.