EP3051140A1 - Stator disc for a vacuum pump - Google Patents

Abstract

A stator disk (24) for a vacuum pump (10), in particular for a turbomolecular pump, comprises an inner ring (66) and an outer ring (68) and stator blades (70) arranged between them, each with webs (72, 74) with the inner ring (66) and the outer ring (66) are connected. The stator disk (24) is designed as a laminated stator disk with restricted stator blades (70) and an outer ring (68) divided in the circumferential direction into a number of separate circular ring cutouts (76) corresponding in particular to the number of stator blades. A method for producing such a stator disk (24) is also disclosed.

Description

The present invention relates to a stator disk for a vacuum pump, in particular for a turbomolecular pump. It further relates to a method for producing such a stator disk and a vacuum pump, in particular turbomolecular pump.

Vacuum pumps such as turbomolecular pumps are used in various fields of technology to create a vacuum necessary for a particular process. Turbomolecular pumps comprise a stator having a plurality of stator disks successive in the direction of a rotor axis, and a rotor mounted rotatably relative to the stator about the rotor axis and comprising a rotor shaft and a plurality of rotor disks arranged successively in the axial direction and arranged between the stator disks on the rotor shaft Stator discs and the rotor discs each have a pump-active structure.

The larger the rotor diameter of vacuum pumps or turbomolecular pumps, the greater will be the pressure forces acting on the rotor and stator disks in the event of sudden gas collapse. However, even in such a case, they must not bend so far that contact between the rotor and the stator occurs. Therefore, it is necessary to select a sheet metal plate made of sheet metal a correspondingly large sheet thickness in order to obtain the necessary rigidity. In the context of this disclosure, "laminated" stator disks are, in particular, those stator disks which have been punched out of a metal sheet and, in particular, have not been obtained by sawing out of a metal sheet.

Due to the corresponding larger sheet thickness, the previously customary measures for stiffening the stator disks, for example a respective flange, can no longer be realized. If, however, a stator disc is distorted when the stator blades are required to be interlaced, the usual methods for straightening the blades following the cabinets are no longer applicable.

However, since stresses occur in the stator disk during the setting process, a subsequent straightening process is required. The stresses that occur when the stator blades are locked are attributable to the fact that the individual stator blades only deform elastically during the torsion, and the blades therefore endeavor to return to their original shape after the shredding process. The inner ring of a respective stator disk is thereby rotated in such a way that the stator disk can no longer be used due to the overall unevenness occurring. Even a repressing or increasing the pressure during Schränkvorgang lead to no better result.

The undesirable deformation or unevenness of the stator disc is mainly due to the fact that the stator blades by the Schränkvorgang an internal stress is impressed by torsion, which leads with simultaneous rigid connection of the stator blades via webs to an inner and outer ring to deform these rings.

The invention has for its object to provide a stator for a vacuum pump, in particular for a turbomolecular pump, and to provide a method for producing such a stator, with which the aforementioned problems are eliminated. In particular, the stator disk should remain at least substantially free of internal stresses, even if it is manufactured as a laminated stator disk from a thicker metal sheet.

The object is achieved by a stator with the features of claim 1 and a method having the features of claim 6. Preferred embodiments of the stator according to the invention as well as preferred embodiments of the method according to the invention will become apparent from the dependent claims, the present description and the drawings.

The stator disk according to the invention for a vacuum pump, in particular for a turbomolecular pump, comprises an inner ring and an outer ring and stator vanes arranged between them, which are each connected via webs to the inner ring and the outer ring. Here, the stator is designed as a laminated stator with staged stator blades and a circumferentially divided into a number of separate circular ring cutouts outer ring. The number of the circular ring cutouts corresponds in particular to the number of stator blades, i. For each stator blade, a circular ring cutout is provided. This is not mandatory. A subdivision of the outer ring can in principle also only e.g. take place on every second stator blade.

The term "circular segment" is to be understood broadly and generally in the sense of "segment", i. the segments forming the outer ring do not have to be parts of a circular ring in a geometrically strict sense.

Due to the construction according to the invention, a respective stator disk can now also be produced from a thicker sheet metal. Thus, even if the stator disk is made as a laminated stator disk from a thicker metal sheet, it remains at least substantially free of internal stresses. Since the outer ring of the stator disk is subdivided, preferably (but not necessarily), into a number of separate circular cut-outs or segments corresponding to the number of stator blades, the stresses introduced into the blades by the stator blade cabinets can subsequently be applied be dismantled again. As a result, the stator blades can each turn back to their original shape. The angles between the inner ring and the inner blade edges and the angle between the outer ring and the outer blade edges and thus the torsion of the webs, which connect the blades to the inner and outer ring, remain at least substantially constant at the desired value. The straightening process following the setting process can be limited to the torsion of the blades. The torsion of the bars remains untouched. In particular, thicker laminated stator disks can thus be realized. Even with vacuum pumps or turbomolecular pumps with a larger rotor diameter can thus be minimized by the use of thicker and correspondingly stiffer blazed stator discs manufacturing costs. Since the elastic deformations can be reduced again immediately after the straightening process, it is impossible for such stresses to dissipate during operation due to heat in the pump and lead to unwanted deformations of the stator disk. Another cost saving results from the fact that only a single straightening tool is needed.

The thickness or sheet thickness of the stator disk is preferably more than 0.5 mm and in particular more than 1.0 mm. Preferably, the thickness is about 1.5mm. In principle, however, the invention also applies to stator disks made of thinner metal sheets. In addition, stator disks according to the invention can also have thicknesses which are more than 1.5 mm.

Preferably, the separate circular ring cutouts of the outer ring are each connected via at least one web to a stator blade.

It is particularly advantageous if the separate circular ring cutouts of the outer ring are each aligned radially with a stator blade.

The circumferentially successive circular ring cutouts of the outer ring are preferably separated from each other by radial slots.

With the usual storage of the stator in a spacer ring of the vacuum pump or turbomolecular pump despite the subdivision of the stator in circular cutouts still a surface connection of the outer rings and thus ensures optimal thermal connection of the stator to the stator.

By fixing a respective stator by spacers on the outer ring arise despite the subdivided in circular ring cutouts outer ring at least substantially no losses in terms of rigidity.

The inventive method for producing a stator for a vacuum pump, in particular for a turbomolecular pump, is characterized in that the stator is made of a formed by a sheet body as a laminated stator with an inner ring, an outer ring and arranged between these stator blades, respectively are connected by webs with the inner ring and the outer ring, wherein the outer ring of the stator in the circumferential direction into a, in particular the number of stator blades corresponding, number of separate circular ring sections is divided, the stator blades are set and the stator blades are then directed to the desired Set Schränkwinkel the stator blades and the separated circular ring sections of the outer ring in their initial position due, in which they at least substantially parallel to each other again in a common Lie flat.

In particular, the blade height can also be adjusted to a particular desired value by the setting of the stator blades.

By eliminating the rigid connection of the stator vanes to the outer ring, the twisted stator vanes can relax after cupping, thus achieving the desired flatness of the stator disk. The individual circular ring sections of the outer ring can turn back to their original shape. The angle between the inner ring and the inner blade edge and the angle between the outer ring and the outer blade edge and thus the torsion of the webs, which connect the stator blades to the inner and outer ring, remain at least substantially constant at the desired value. The subsequent straightening process can be limited to the torsion of the stator blades, whereby the respective desired angles are obtained. The stator disks can thus also be made of relatively thick sheets having a thickness of e.g. 1 mm or 1.5 mm, so that the manufacturing costs are minimized by the use of blazed stator discs even with vacuum pumps or turbomolecular pumps with larger rotor diameters. Since all elastic deformations can break down immediately after the straightening process, the stator disks are finally free of tension. This eliminates the risk that stresses in the pump can dissipate during operation due to heat and lead to unwanted deformations of the stator disk. In addition, only a straightening tool is needed, which contributes to further minimization of costs.

With the repealed rigid connection of the stator blades to the outer ring and the concomitant relaxation of the twisted stator blades, the desired flatness of the stator disk is created after the straightening process. With the usual fixation of a respective stator by spacer rings on the outer ring results in spite of the subdivided outer ring still a surface connection of the outer ring in each spacer ring of the vacuum pump or turbomolecular pump, which in particular an optimal thermal connection is guaranteed.

The outer ring of the stator can be divided both before and after the cabinets of the stator blades in the separate circular ring cutouts.

The straightening of the stator blades is advantageously carried out while maintaining the twisting of the stator blades caused torsion of the webs.

According to a preferred practical embodiment of the method according to the invention for directing the stator blades adjacent to the inner ring edges of the stator blades are each fixed by two particular point-shaped elements of a straightening tool and positioned on the outer ring adjacent edges of the stator blades in particular two punctiform elements of the straightening tool, through which axial pressure the required torsion of the stator blades is brought about.

In this case, to adjust the desired Schränkwinkels the stator blades and for returning the separate circular ring sections of the outer ring in its initial position, the stator blades are preferably slightly overrun when straightening.

The stator can be divided in particular by punching, cutting, lasering, milling or sawing in the separate circular ring cutouts.

Preferably, the outer ring of the stator is divided by forming slot-like radial recesses in the circumferentially successive circular cutouts.

With the usual fixation of a respective stator by spacers resulting from the subdivision of the outer ring virtually no losses in terms of rigidity of the stator against bending. To stabilize the stator, however, the circumferentially successive circular sections of the stator can be treated or edited after straightening the stator blades, for example by riveting, welding, overmolding with plastic or the like. The segments can also be connected to each other again, but such a reunion is not mandatory.

The vacuum pump according to the invention, in particular turbomolecular pump, comprises a stator with a plurality of stator disks successive in the direction of a rotor axis and a rotor rotatably mounted about the rotor axis relative to the rotor, comprising a rotor shaft and a plurality of arranged on the rotor shaft, in the axial direction and successive arranged between stator disks rotor disks , Wherein the stator disks and the rotor disks each have a pump-active structure and stator disks according to the invention are provided as stator disks.

The stator disks may each consist in particular of part-circular parts, wherein they preferably each consist of two semicircular parts.

With the solution according to the invention can now be easily made of thicker sheet metal stator discs are used, which can take into account the fact that with increasing diameter of the stator of vacuum pumps and turbomolecular pumps in particular at the same pressure, the pressure forces acting on the stator increases sharply, resulting in the result has that for larger pumps thicker material must be used, as was previously the case with smaller pumps. Due to the solution according to the invention unlike previously no relatively expensive stator more need to be used. These can now by laminated stator discs be replaced, whereby the costs are significantly minimized. The laminated stator discs can now have a corresponding thickness, for example, a thickness in the range of 1.5 mm, which can withstand the higher pressure forces in case of unforeseen flooding events.

The laminated stator disks are made by first stamping the profile and then setting the individual blades. While in the previous stator disks with a continuous outer ring when cabinet so large residual stresses occurred by elastic deformation in the blades that these were only partially deformed elastically, so that the discs could not be used afterwards, is created by the inventive cutting of the outer ring remedy , By cutting the outer ring between each blade according to the invention, the stresses can be reduced. Although the individual outer ring elements or circular ring cutouts are initially skewed after the setting process, they can subsequently be directed. By the straightening process in question, the desired torsion can be achieved by means of plastic deformation by slightly overbending, which was previously not possible in view of the continuous outer ring. With the severing of the outer ring, the stability of the stator is at most slightly influenced. In the usual fixation of the stator by spacer rings on the outer ring, however, there is virtually no higher risk of sagging of the stator. Nevertheless, in principle it is also conceivable, for further stabilization of the stator disks, to reconnect the initially separate circular ring cutouts of the outer ring after the straightening process, for example by riveting, welding or encapsulating with plastic.

By cutting the outer ring of the stator disks according to the invention, even thicker sheets can be processed to form stator disks, since they can be oriented by cutting them through. This allows the best possible To find a compromise between deflection and pumping speed, even with larger Statorscheibendurchmessern. This means that even with larger vacuum pumps or larger turbomolecular pumps, the cost advantage of flat stator disks can be used.

Fig. 1

eine schematische Darstellung einer beispielhaften Ausführungsform einer Vakuumpumpe, bei der erfindungsgemäße Statorscheiben einsetzbar sind,

Fig. 2

eine schematische Draufsicht eines halbkreisförmigen Teils einer aus zwei solchen halbkreisförmigen Teilen bestehenden beispielhaften Ausführungsform einer erfindungsgemäßen Statorscheibe, und

Fig. 3

eine schematische Ansicht des halbkreisförmigen Statorscheibenteils gemäß Fig. 2 in Richtung des Pfeils A der Fig. 2.

The invention will be explained in more detail below with reference to an embodiment with reference to the drawing; in this show:

Fig. 1

a schematic representation of an exemplary embodiment of a vacuum pump can be used in the stator according to the invention,

Fig. 2

a schematic plan view of a semi-circular portion of an existing of two such semi-circular parts exemplary embodiment of a stator according to the invention, and

Fig. 3

a schematic view of the semicircular Statorscheibenteils according to Fig. 2 in the direction of arrow A the Fig. 2 ,

In the Fig. 1 The vacuum pump 10 shown includes a pump inlet 14 surrounded by an inlet flange 12, and a plurality of pumping stages for delivering the gas present at the pump inlet 14 to an in Fig. 1 not shown pump outlet. The vacuum pump 10 comprises a stator with a static housing 16 and a rotor arranged in the housing 16 with a rotor shaft 20 rotatably mounted about a rotation axis 18.

The vacuum pump 10 is designed as a turbomolecular pump and comprises a plurality of pump-effectively connected in series with each other in turbomolecular pumping stages with a plurality of turbomolecular rotor disks 22 connected to the rotor shaft 20 and a plurality of turbomolecular stator disks 24 arranged in the axial direction between the rotor disks 22 and fixed in the housing 16, which are held at a desired axial distance from one another by spacer rings 26. The rotor disks 22 and stator disks 24 provide in a scooping region 28 an axial pumping action directed in the direction of the arrow 30.

The vacuum pump 10 also comprises three Holweck pumping stages which are arranged one inside the other in the radial direction and which are pumpingly connected to one another in series. The rotor-side part of the Holweck pump stages comprises a rotor hub 32 connected to the rotor shaft 20 and two cylinder shell-shaped Holweck rotor sleeves 34, 36 fastened to and supported by the rotor hub 32, which are oriented coaxially with the rotor axis 18 and are nested in the radial direction. Furthermore, two cylindrical jacket-shaped Holweck stator sleeves 38, 40 are provided, which are also oriented coaxially to the axis of rotation 18 and are nested in the radial direction. The pump-active surfaces of the Holweck pump stages are each formed by the radial lateral surfaces of a Holweck rotor sleeve 34, 36 and a Holweck stator sleeve 38, 40 opposite each other, forming a narrow radial Holweck gap. In each case, one of the pump-active surfaces is smooth, in the present case, the Holweck rotor sleeve 34 and 36, and the opposite pump-active surface of the Holweck stator 38, 40 has a structuring with helically around the rotation axis 18 in the axial direction extending grooves on, in which by the rotation of the rotor, the gas is driven and thereby pumped.

The rotatable mounting of the rotor shaft 20 is effected by a roller bearing 42 in the region of the pump outlet and a permanent magnet bearing 44 in the region of the pump inlet 14.

The permanent magnet bearing 44 comprises a rotor-side bearing half 46 and a stator bearing half 48, each comprising a ring stack of a plurality of stacked in the axial direction of permanent magnetic rings 50, 52, wherein the magnetic rings 50, 52 opposite to form a radial position gap 54.

Within the permanent magnet bearing 44, an emergency or fishing camp 56 is provided, which is designed as an unlubricated rolling and idle in normal operation of the vacuum pump without touching and passes only at an excessive radial deflection of the rotor relative to the stator into engagement to a radial stop for to form the rotor, which prevents a collision of the rotor-side structures with the stator-side structures.

In the area of the rolling bearing 42, a conical injection nut 58 with an outer diameter increasing towards the roller bearing 42 is provided on the rotor shaft 20, which is in sliding contact with a wiper of a plurality of operating medium, such as a lubricant, impregnated absorbent disks 60 containing operating fluid storage stands. In operation, the resource is transferred by capillary action of the resource storage on the scraper on the rotating injection nut 58 and due to the centrifugal force along the injection nut 58 in the direction of increasing outer diameter of the sprayer 58 to the roller bearing 42 out promoted, where there is, for example, a lubricating Function fulfilled.

The vacuum pump includes a drive motor 62 for rotatably driving the rotor whose rotor is formed by the rotor shaft 20. A control unit 64 controls the drive motor 62.

The turbomolecular pumping stages provide a pumping action in the direction of the arrow 30 in the scooping region 28.

Fig. 2 shows a schematic plan view of a semicircular part of an existing of two such semi-circular parts exemplary embodiment of a stator 24 according to the invention for a vacuum pump. Such a stator disk 24 can be used for example in a vacuum pump 10 or turbomolecular pump, as in connection with the Fig. 1 has been described. In Fig. 3 is the semicircular Statorscheibenteil according to Fig. 2 shown again in a schematic view in the direction of arrow A.

The stator disk 24 comprises an inner ring 66 and an outer ring 68 and stator blades 70 arranged between them, which are each connected via inner webs 72 and outer webs 74 to the inner ring 66 and the outer ring 68.

In this case, the stator disk 24 is made of a basic body formed by a metal sheet as a laminated stator disk with restricted stator blades 70 and an outer ring 68 divided in the circumferential direction into one of the number of stator blades 70 corresponding to a number of separate circular ring cutouts 76.

As based on the Fig. 2 can be seen, the separate annular recesses 76 of the outer ring 68 are each connected via a single outer web 74 with a respective stator blade 70. The separate annular recesses 76 of the outer ring 68 are each radially aligned with the respective stator blade 70.

In the present case, the circumferentially successive circular cutouts 76 of the outer ring 68 are separated from each other by radial slots 78.

The separate annular recesses 76 of the outer ring 68 of the finished stator disc 24 are arranged parallel to each other in a common plane

To produce a corresponding stator disk 24, the stator disk 24 is made of a base body formed by a sheet as a laminated stator with an inner ring 66, an outer ring 68 and between these arranged stator blades 70, respectively via inner webs 72 and outer webs 74 are connected to the inner ring 66 and the outer ring 68, respectively.

The outer ring 68 of the stator disk 24 is divided in the circumferential direction into a number of separate annular cutouts 76 corresponding to the number of stator blades 70. Stator vanes 70 are constrained and then straightened to set the desired taper angle of stator vanes 70 and return the separated annular recesses 76 of outer race 68 to their initial position where they are at least substantially parallel to each other again in a common plane.

In this case, the outer ring 68 of the stator disc 24 before or after the cabinets of the stator blades 70 in a number of stator blades 70 corresponding number of separate circular cutouts 76 are divided.

The straightening of the stator blades 70 takes place while maintaining the torsion of the webs 72, 74 effected with the cabinets of the stator blades 70.

To this end, for directing the stator blades 70, the edges 80 of the stator blades 70 adjacent to the inner ring 66 can each be fixed in particular by two punctiform elements of a straightening tool (not shown) and in particular two point-shaped elements of the straightening tool are positioned on the edges 62 of the stator blades 70 adjacent to the outer ring 68 are, over which by axial pressure, the required torsion of the stator blades 70 is brought about.

To set the desired Schränkwinkels the stator blades 70 and for returning the separated circular ring cutouts 76 of the outer ring 68 in its initial position, the stator blades 70 can be easily over-tightened in straightening.

In particular, the stator disk 24 can be subdivided into a number of separate circular ring cutouts 76 corresponding to the number of stator blades 70 by punching, cutting, lasering or milling. In this case, the subdivision of the outer ring 68 of the stator disc 24 in the circumferentially successive circular cutouts 76 in particular by slotted radial recesses or radial slots 78 take place.

However, the gaps or interruptions between the segments of the outer ring need not be slit-like. Also, no or at least no continuous radial extent of these spaces or interruptions is mandatory. Design and form of the spaces or interruptions are basically arbitrary and in particular to choose depending on the thickness of the sheet used and the dimensions of the stator.

In a conventional fixation of the stator 24 by spacers on the outer ring 68 results in virtually no significant losses in terms of rigidity of the stator 24 and, accordingly, virtually no increase in risk a bending of the stator. To increase the stability of the stator 24, however, is also conceivable that the circumferentially successive circular cutouts 76 of the stator 24 after machining the stator blades 70, for example, by riveting, welding, molding with plastic or the like processed and / or also connected to each other again.

LIST OF REFERENCE NUMBERS

10

vacuum pump

12

inlet flange

14

pump inlet

16

casing

18

axis of rotation

20

rotor shaft

22

rotor disc

24

stator

26

spacer

28

adding area

30

arrow

32

rotor hub

34

Holweck rotor sleeve

36

Holweck rotor sleeve

38

Holweck stator

40

Holweck stator

42

roller bearing

44

Permanent magnetic bearings

46

Rotor-side bearing half

48

stator side half

50

permanent magnetic ring

52

permanent magnetic ring

54

radial bearing gap

56

Emergency or fishing camp

58

conical spray nut

60

absorbent disc

62

drive motor

64

control unit

66

inner ring

68

outer ring

70

stator

72

inner jetty

74

outer bridge

76

Circular ring section

78

radial slot, radial recess

80

inner edge

82

outer edge

Claims (15)

Stator disc (24) for a vacuum pump (10), in particular for a turbomolecular pump, with an inner ring (66) and an outer ring (68) and between these arranged stator blades (70), each via webs (72, 74) with the inner ring ( 66) and the outer ring (68) are connected, wherein the stator disc (24) as a laminated stator with staged stator blades (70) and in the circumferential direction in one, in particular the number of stator blades (70) corresponding, number of separate circular ring cutouts (76 ) divided outer ring (68) is executed. Stator disc according to claim 1,
characterized in that the separate annular recesses (76) of the outer ring (68) are each connected via at least one web (74) with a stator blade (70). Stator disk according to claim 1 or 2,
characterized in that the separate annular recesses (76) of the outer ring (68) are each radially aligned with a stator blade (70). Stator disk according to at least one of the preceding claims,
characterized in that in circumferential direction consecutive annular cut-outs (76) of the outer ring (68) (78) are separated from one another by radial slots. Stator disk according to at least one of the preceding claims,
characterized in that the separate circular ring cutouts (76) of the outer ring (68) are arranged parallel to each other in a common plane. Method for producing a stator disk (24) for a vacuum pump, in particular for a turbomolecular pump, in which the stator disk (24) consists of a base body formed by a sheet metal as a laminated stator disk with an inner ring (66), an outer ring (68) and between them Stator blades (70) is produced, which in each case via webs (72, 74) with the inner ring (66) and the outer ring (68) are connected, wherein the outer ring (68) of the stator disc (24) in the circumferential direction in one, in particular the number the stator blades (70) are separated, the stator blades (70) are constrained, and the stator blades (70) are then directed to set the desired taper angle of the stator blades (70) and the spaced apart annulus sections (76) of the outer ring (68) due to their initial position in which they at least substantially again lie parallel to each other in a common plane. Method according to claim 6,
characterized in that the outer ring (68) of the stator disc (24) before the cabinets of the stator blades (70) is divided into the separate circular ring cutouts (76). Method according to claim 6,
characterized in that the outer ring (68) of the stator disc (24) after the cabinets of the stator blades (70) is divided into the separate circular ring cutouts (76). Method according to one of claims 6 to 8,
characterized in that the straightening of the stator blades (70) while maintaining the torsion of the stator blades (70) caused torsion of the webs (72, 74) takes place. Method according to one of claims 6 to 9,
characterized in that for straightening the stator blades (70) the edges (80) of the stator blades (70) adjacent to the inner ring (66) are respectively fixed by two punctiform elements of a straightening tool and to the edges (82) of the outer ring (68) Stator blades (70) are each positioned in particular two punctiform elements of the straightening tool over which by axial pressure, the required torsion of the stator blades (70) is brought about. Method according to claim 10,
characterized in that for adjusting the desired Schränkwinkels the stator blades (70) and for returning the separate circular ring sections (76) of the outer ring (68) in their initial position, the stator blades (70) are slightly over-turned during straightening. Method according to one of claims 6 to 11,
characterized in that the stator disc (24) by punching, cutting, laser cutting or milling in the separate circular ring cutouts (76) is divided. Method according to one of claims 6 to 12,
characterized in that the outer ring (68) of the stator disc (24) is subdivided into the circumferentially successive circular cutouts (76) by forming slot-like radial recesses (78). Method according to one of claims 6 to 13,
characterized in that the circumferentially successive circular ring cutouts (76) of the stator disc (24) after straightening the stator blades (70) by riveting, welding, encapsulation with plastic or the like stabilized and / or reconnected. Vacuum pump (10), in particular turbomolecular pump, comprising a stator which comprises a plurality of stator disks (24) arranged successively in the direction of a rotor axis (18) and a rotor which is rotatably mounted relative to the stator about the rotor axis (18) and which has a rotor shaft (20) and several on the Rotor rotor (20) arranged in succession in the axial direction and between the stator (24) arranged rotor disks (22), wherein the stator disks (24) and the rotor disks (22) each having a pump-active structure and the stator disks (24) according to one of Claims 1 to 5 executed and / or produced by a method according to any one of claims 6 to 13.

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