EP2863063A2 - Vacuum pump - Google Patents

Abstract

The invention relates to a vacuum pump with a stator having a plurality of successive in the direction of a rotation axis stator discs, each having a pump-active structure, and with a relative to the stator rotatably mounted about the axis of rotation rotor having a rotor shaft and a plurality of rotor shaft arranged in the axial Direction of successive and arranged between the stator disks rotor disks, each having a pump-active structure, wherein at least one rotor disc defines a formed between the rotor disk and the stator radial sealing gap, and wherein at least one stator-side sealing portion is provided, which the sealing gap in the axial direction viewed against the conveying direction at least partially covers and with respect to the conveying direction before and / or next to the pump-active structure of the following in the conveying direction on the rotor disk stator disk is arranged.

Description

The present invention relates to a vacuum pump, in particular a turbomolecular pump.

Vacuum pumps, e.g. 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 rotational axis, each having a pump-active structure, and a rotatably mounted about the axis of rotation relative to the stator, the rotor shaft and a plurality of arranged on the rotor shaft, successively in the axial direction and between the Stator discs arranged rotor discs comprises, each having a pump-active structure.

Due to the design, such a vacuum pump has dynamic sealing areas, for example sealing gaps between the radial outer ends of the rotor disks and the stator or between the radial inner ends of the stator disks and the rotor, which due to their insufficient tightness allow undesired backflow of the gas counter to the conveying direction , which lowers the suction power and the compression of the vacuum pump. A reduction in the gap widths of existing sealing gaps to reduce the backflow is only partially possible because too small gap widths the risk of collision between the rotor and the stator in the operation of the vacuum pump and the cost of producing the vacuum pump due to the higher demands on the Tolerances of the components increases.

Out DE 20 2010 011 796 U1 a turbomolecular pump is known in which between at least one stator element and at least one adjacent rotor element for reducing the gas backflow, a diaphragm element is provided, which is integrally formed with the stator and is disposed between the stator and the following in the conveying direction on the stator rotor element. This is intended to reduce backflow through the radial sealing gap formed between the radially outer side of the upstream rotor element and the stator. The gas is to be deflected by the diaphragm element in the radial direction inwards, so that it can not pass through the radially outer sealing gap between the upstream rotor element and the stator.

Nevertheless, a return flow through this sealing gap takes place, since the back-flowing gas can flow on the way through the stator in the radial direction outward and thereby can reach into the region of the radial sealing gap of the upstream Rotortscheibe. In addition, the baffles increase the axial height of the vacuum pump and must be provided as additional elements and attached to the stator elements, whereby the cost of providing the vacuum pump is increased.

The object of the invention is therefore to provide a vacuum pump, which has an improved pump performance, in particular a high pumping speed and high compression, and can be provided with little effort.

The object is achieved by a vacuum pump with the features of claim 1.

The vacuum pump, which is in particular a turbomolecular pump, comprises a stator having a plurality of stator disks successive in the direction of a rotation axis, each having a pump-active structure, and a rotor rotatably mounted about the rotation axis relative to the stator, having one rotor shaft and a plurality of rotor shafts arranged on the rotor shaft , in the axial direction comprises successive and arranged between the stator disks rotor disks, each having a pump-active structure. At least one rotor disk defines a radial sealing gap formed between the rotor disk and the stator. At least one stator-side sealing section is provided which at least partially covers the sealing gap in the axial direction counter to the conveying direction and is arranged in front of and / or next to the pump-active structure of the stator disk following the conveying direction on the rotor disk.

The sealing section covers the sealing gap in the axial direction and thereby represents an obstacle to an axial backflow of the gas passing through the sealing gap. Since the sealing section is arranged in front of and / or next to the pump-active structure of the downstream stator disk, the sealing section prevents the sealing section in that, in the region of the pump-active structure of the stator disk, backflowing gas flows on its return path through the stator disk in the radial direction to the sealing gap of the upstream rotor disk and consequently can pass into the sealing gap after passing through the stator disk and can flow back further through the sealing gap. Instead, at most the gas can flow back through the stator disk in a region remote from the sealing gap and, therefore, after any backflow through the stator disk, is detected by the pump-active structure of the upstream rotor disk, which redirects the gas in the conveying direction. The sealing section thus reduces the backflow and increases the pump performance.

Advantageous embodiments of the invention are described in the subclaims, the description and the figures.

According to an advantageous embodiment, the sealing portion covers the sealing gap over its entire radial gap width away. As a result, a particularly effective sealing is achieved, which ensures a high pumping speed and high compression of the vacuum pump. The rotor disk can engage behind the sealing section in the radial direction, in particular in order to ensure that the sealing gap is covered by the sealing section over the entire gap width of the sealing gap.

The sealing portion is preferably annular. The sealing portion may cover the sealing gap over at least approximately the entire circumference of the rotor disk.

According to an advantageous embodiment, the stator disk has a ring, in particular an outer ring, which carries the pump-active structure of the stator disk, wherein the sealing portion is formed by the ring of the stator disk. By forming the pump-active structure supporting ring of the stator as a sealing portion, an additional effort for the provision of the sealing portion and an additional space requirement for the sealing portion is largely avoided. For example, a stator disk with an outer ring can be used to form the sealing section, which has a relatively large radial width and covers the radial sealing gap of the preceding rotor disk.

A further embodiment provides that the sealing portion is formed by a spacer ring, which holds two axially successive stator disks at an axial distance from each other. Such spacers are already favorable, by a predetermined axial distance between the stator discs to be maintained, and can be easily modified so that they form a sealing portion for covering the radial sealing gap of the upstream rotor disk. The radial sealing gap can be limited by a portion of the spacer ring and the sealing portion may be formed by a portion of the spacer ring which protrudes in the radial direction relative to the portion of the spacer ring which limits the sealing gap and in particular forms a shoulder of the spacer ring.

The formation of the sealing portion by a spacer ring is particularly advantageous if the stator disc following in the conveying direction of the rotor disc no ring arranged in the region of the sealing gap, that is, for example, no outer ring has. For example, such a stator disk may be machined from a solid body by material removal, while a stator disk may be formed with an outer ring, e.g. may be formed as a laminated stator disc, i. as a stator, which is made by deformation of a base body formed by a metal sheet.

According to an advantageous embodiment of the sealing portion of the spacer ring defines a groove which extends in the radial direction in the spacer ring. The rotor disk can engage in the groove, preferably in the radial direction. The radial sealing gap can be limited by the rotor disk and by the groove bottom. The side walls of the groove preferably cover the sealing gap in each case in the axial direction. This embodiment has the advantage that the sealing gap with respect to the axial direction not only on one side, but on both sides, that is both in the downstream direction and in the upstream direction, is covered by a respective side wall of the groove. The side walls of the groove can each define one of two axial sealing gaps adjoining the radial sealing gap with the rotor disk. As a result, a particularly effective sealing of the radial sealing gap is achieved.

According to an advantageous embodiment, the spacer ring is divided in the radial direction such that the spacer ring and the rotor disk can be assembled in the axial direction. This is particularly advantageous if the spacer ring, as described above, has a radial groove into which the rotor disk engages radially. In this case, the spacer ring may be divided in the radial direction in the region of the groove in order to allow axial assembly. The possibility of axial assembly of the required for the production of the vacuum pump effort is significantly reduced.

According to a preferred embodiment, the rotor disk has at least one radial projection, which preferably protrudes in the radial direction from the pump-active structure of the rotor disk, wherein the radial sealing gap is limited at least in sections by the extension. Such an extension can be adapted to ensure a particularly good sealing of the sealing gap, so that a return flow is particularly reliably avoided. The extension is preferably formed gas-tight throughout to ensure the best possible seal. It is preferred if the rotor disk engages with the extension in a radial groove of a spacer ring as described above. For example, the extension may be annular and / or extend over at least approximately the entire circumference of the rotor disk. The pump-active structure can have a plurality of pump-active elements, in particular blades, wherein a radial extension extending in particular over the entire circumference of the rotor disk can be carried by a plurality of pump-active elements and / or a plurality of separate radial extensions of the type described can be provided stand out different pump active elements. However, the radial extension can also be designed as a radial extension of the blades in the region of the groove.

Preferably, the extension extends only over part of the axial extent of the pump-active structure of the rotor disk. As a result, the additional cost of materials and the additional weight of the rotor disc formed by the extension is kept small and yet a targeted and extremely effective sealing of the sealing gap can be achieved. If the sealing portion, as described above, is formed by a spacer ring with a groove, in which engages the extension, preferably also the groove extends only over part of the axial extent of the pump-active elements of the rotor disc. It can thereby be achieved that the groove walls closely surround the extension on all sides, so that the radial sealing gap is preferably accessible only via axial gaps, as a result of which the backflow is further reduced.

Another object of the invention is a vacuum pump with the features of claim 8.

The vacuum pump comprises a stator having a plurality of stator disks successive in the direction of a rotation axis, each having a pump-active structure, and a rotatably mounted about the rotation axis relative to the rotor, the rotor shaft and a plurality of rotor shaft arranged on the rotor shaft, successively in the axial direction and between The stator disks arranged rotor disks comprises, each having a pump-active structure. At least one stator disk and / or at least one rotor disk defines a radial sealing gap formed between the stator and the rotor. The sealing gap extends at least partially obliquely to the axis of rotation.

Characterized in that the sealing gap extends at least in sections, and in particular over its entire length obliquely to the axis of rotation, the length of the sealing gap is increased and improves its tightness. As explained in detail below, such an oblique sealing gap can also be realized particularly easily, for example by the sealing gap is at least partially bounded by a foot portion or collar portion of the rotor disc, which runs obliquely to the axis of rotation. The oblique sealing gap or one or each oblique section of the sealing gap may have a straight or curved shape or may extend in a stepped manner in a direction oblique to the axis of rotation.

The sealing gap defining surfaces are opposite each other in the radial direction and are preferably at least approximately parallel to each other. The gap preferably has an at least approximately constant gap width.

Below, advantageous embodiments of the vacuum pump are described according to claim 8. This vacuum pump can be designed simultaneously as a vacuum pump according to claim 1. Accordingly, the advantages and advantageous embodiments described herein with respect to the vacuum pump according to claim 1 are also advantages and advantageous embodiments of the vacuum pump according to claim 8.

The vacuum pump is preferably a turbomolecular pump. The vacuum pump may also be a side channel pump.

According to an advantageous embodiment, a stator disk bounding the sealing gap and / or a rotor disk bounding the sealing gap has a ring, in particular an inner ring, which carries the pump-active structure of the respective disk, wherein at least a portion of the sealing gap extending obliquely to the axis of rotation is limited by the ring of the stator and / or limited by the ring of the rotor disk. As a result, a sealing gap with advantageous properties can be created without additional elements. The ring of the rotor disk is preferably arranged on the rotor shaft in order to connect the rotor disk to the rotor shaft.

According to one embodiment, a ring of the rotor disk bounding the sealing gap, in particular an inner ring, has a collar portion projecting in the axial direction, wherein at least a portion of the sealing gap extending obliquely to the axis of rotation is bounded by the collar portion. The collar portion is preferably connected to the rotor shaft and thus can simultaneously serve in the context of the invention for connecting the rotor disk to the rotor shaft and for providing the oblique to the axis of rotation sealing gap.

The collar portion may be formed integrally with either the shaft or executed as a separate part and connected to the shaft.

The collar portion may have a radially widening in the radial direction to the rotor shaft shape, whereby a mechanically particularly good connection of the rotor disk with the rotor shaft can be created. A surface of the collar section which is present in the area of the broadening can serve to limit at least one section of the sealing gap which is inclined to the axis of rotation. The oblique section of the sealing gap can extend in the axial direction from the rotor disk to the stator disk in the radial direction toward the rotor shaft. Characterized in that the gap between the widening collar portion and the stator is formed as an oblique sealing gap or sealing gap portion, a good sealing effect is achieved in this area and it avoids the problem that the widening shape of the collar portion an extended gap between the rotor and the stator, which allows excessive backflow.

According to an advantageous embodiment, a sealing gap defining ring, in particular the stator, a projecting in the radial direction extension, wherein at least a portion of the sealing gap, which extends obliquely to the axis of rotation, is limited by the extension. Preferably, an extension of the stator disc defines the oblique portion of the sealing gap together with a collar portion of the rotor disk as described above. As described above, the design of the gap between the collar portion and the stator as a sealing gap or sealing gap portion prevents high backflow in the region of the widening collar portion. The stator disc with the ring and the extension is preferably formed integrally by a single body.

According to an advantageous embodiment, the sealing gap has at least two sections which run obliquely to the axis of rotation and at an angle to each other, wherein preferably both sections are each bounded by a stator on the one hand and one of two adjacent to the stator disc rotor discs on the other. The two sections can form a V-shaped sealing gap. Both sections may be bounded by a radially projecting extension of the stator disk as described above on the one hand and a collar section of the respective rotor disk on the other hand. The two sections of the sealing gap can extend in the radial direction inward in the radial direction from the respective rotor disk to the stator disk, or the vertex of the V-shape of the sealing gap can point towards the rotor shaft.

Another object of the invention is a vacuum pump with the features of claim 13.

The vacuum pump comprises a stator having a plurality of stator disks successive in the direction of a rotation axis, each having a pump-active structure, and a rotatably mounted about the rotation axis relative to the rotor, the rotor shaft and a plurality of rotor shaft arranged on the rotor shaft, successively in the axial direction and between The stator disks arranged rotor disks comprises, each having a pump-active structure. The pump-active structures of the stator disks and rotor disks are designed to provide a pumping action oriented in a conveying direction for a gas present in a scooping area. There is a sealing area adjacent to the scoop area, which is bounded at least partially by a stator disk and a rotor disk adjacent to the stator disk. Opposite surfaces of the rotor and of the stator which delimit the sealing area form at least one pumping stage for providing a pumping action for the gas present in the sealing area, which counteracts a backflow of the gas through the sealing area.

For the purposes of the present description, the scoop area generally refers to the area in which the pump-active structures of the stator disks and rotor disks provide a pumping action, oriented in a conveying direction, for the gas present there. A sealing region is understood to mean a region which adjoins the scooping region and through which, in principle, a return flow of the gas directed counter to the conveying direction can take place.

Characterized in that opposing and the sealing area limiting surfaces of the rotor and the stator form at least one pumping step for providing a pumping action for the gas present in the sealing area, which counteracts a backflow of the gas through the sealing area, the backflow is reduced and the pumping power of the vacuum pump improved.

In one possible development, it is provided that at least one of the surfaces forming the pumping stage runs obliquely to the axis of rotation.

Below, advantageous embodiments of the vacuum pump are described according to claim 13. This vacuum pump can be configured simultaneously as a vacuum pump according to claim 1 and / or as a vacuum pump according to claim 8. Accordingly, the advantages and advantageous embodiments described herein with respect to the vacuum pumps according to claim 1 and claim 8 are also advantages and advantageous embodiments of the vacuum pump according to claim 13.

The vacuum pump is preferably a turbomolecular pump. The vacuum pump may also be a side channel pump.

The surfaces forming the pumping stage are preferably formed by the stator disk and the adjacent rotor disk. The pumping stage can thus be realized simply by appropriate adaptation of the surfaces of the stator disk and the rotor disk.

According to an advantageous embodiment, the stator disc has a ring, in particular an inner ring, which carries the pump-active structure of the stator, and the rotor disk has a ring, in particular an inner ring, which carries the pump-active structure of the rotor disk, wherein the pumping stage forming Surfaces are formed by the rings of the stator and the rotor disk. These surfaces are particularly suitable for realizing a pumping stage that reduces backflow.

The surfaces forming the pumping stage preferably face each other in the axial direction. The surfaces may define an axial sealing gap, which is part of the sealing area.

The sealing region may comprise a radial sealing gap between the rotor and the stator and two axial sealing gaps adjoining the radial sealing gap on both sides. The axial sealing gaps are preferably delimited by the same stator or rotor disk and in each case by one of two rotor or stator disks adjacent to the stator or rotor disk or by rings of the stator and rotor disks which carry the pump-active structures of the stator and rotor disks. Preferably, two pumping stages are provided, each formed by the surfaces defining one of the axial sealing gaps and counteracting a backflow.

Preferably, the pumping stage is a Siegbahnpumpstufe. Such a pumping stage is easy to implement and effectively counteracts a backflow. For example, one of the surfaces forming the pumping stage may be smooth and the opposite surface may have at least one helical groove in which the pumped gas is passed. It is also possible to provide a plurality and in particular two Siegbahnpumpstufen, which are preferably, as described above, each associated with an axial sealing gap of the sealing area.

In the following, advantages and advantageous embodiments of all the vacuum pumps described in the present description will be described.

In all the pumps of the present description, the rotor disks and the stator disks are preferably alternately arranged in the axial direction.

The rotor may be formed in one piece or in several parts. In a multi-part rotor, the rotor shaft on the one hand and the rotor disks connected to the rotor shaft on the other hand may be formed as separate parts. The stator can also be designed in several parts. In particular, the stator may include a housing, a plurality of parts connected to the housing and separate from the housing having trained rotor disks and preferably a plurality of connected to the housing and formed as separate from the housing and the rotor disks parts spacer rings.

The stator disks, rotor disks and / or spacer rings can each have a substantially circular basic shape and / or be formed in one piece or in several parts. A multi-part stator or rotor disk or a multi-part spacer ring may, in particular, comprise several and in particular two part-circular parts which together form the respective disk or the spacer ring.

The vacuum pump can be designed as a turbomolecular pump. The stator disks and rotor disks can accordingly be designed as turbomolecular stator and rotor disks with a turbomolecular pump-active structure. The pump-active structures of the rotor disks and the stator disks preferably have a plurality of pump-active elements designed as blades, which are preferably carried by an outer ring and / or by an inner ring of the respective disk. The blades may have an oblique position relative to the axial direction, which serves to deflect the gas molecules coming into contact with the blades in the conveying direction, wherein the oblique position of the blades of the stator disks and the rotor disks is preferably mirror images of one another.

In the case of a side-channel pump, the rotor disks as pump-active structure preferably have rotor blades in the region of their radial outer side, which rotate in a side channel formed by the stator disks, which is widened in relation to the rotor blades. The pump-active structures of the stator disks are formed by the side channel delimiting sections of the stator disks. A side channel can be followed by two consecutive in the axial direction Statorscheiben be limited, between which a rotor disk is arranged with rotor blades.

In the context of the present description, a gap or sealing gap is understood to mean a gap which is narrow in a predetermined direction and has a greater extent in the other directions. A gap or sealing gap can, in principle, have an at least approximately constant gap width in the context of the invention.

Fig. 1

eine Vakuumpumpe gemäß einer Ausführungsform der Erfindung in einer geschnittenen Darstellung,

Fig. 2

den Bereich A der in Fig. 1 gezeigten Vakuumpumpe,

Fig. 3

eine Statorscheibe der in Fig. 1 gezeigten Vakuumpumpe in Draufsicht in einem unfertigen Herstellungszustand,

Fig. 4

einen Ausschnitt der in Fig. 3 gezeigten Statorscheibe,

Fig. 5

die in Fig. 3 und 4 gezeigte Statorscheibe im fertigen Zustand in perspektivischer Darstellung,

Fig. 6

den Bereich B der in Fig. 1 gezeigten Vakuumpumpe,

Fig. 7

den Bereich C der in Fig. 1 gezeigten Vakuumpumpe,

Fig. 8

einen Ausschnitt einer Vakuumpumpe gemäß einer weiteren Ausführungsform der Erfindung in einer geschnittenen Darstellung, und

Fig. 9

den Bereich D der in Fig. 7 gezeigten Vakuumpumpe.

The invention will be described by way of example with reference to advantageous embodiments with reference to the accompanying figures. Show it:

Fig. 1

a vacuum pump according to an embodiment of the invention in a sectional view,

Fig. 2

the area A of in Fig. 1 shown vacuum pump,

Fig. 3

a stator disk of in Fig. 1 shown vacuum pump in plan view in an unfinished state of manufacture,

Fig. 4

a section of in Fig. 3 shown stator disc,

Fig. 5

in the Fig. 3 and 4 shown stator in the finished state in perspective view,

Fig. 6

the area B of in Fig. 1 shown vacuum pump,

Fig. 7

the area C of in Fig. 1 shown vacuum pump,

Fig. 8

a section of a vacuum pump according to another embodiment of the invention in a sectional view, and

Fig. 9

the area D of in Fig. 7 shown vacuum pump.

In the Fig. 1 The vacuum pump shown comprises a pump inlet 70 surrounded by an inlet flange 68 as well as a plurality of pumping stages for conveying the gas present at the pump inlet 70 to a pump inlet 70 Fig. 1 not shown pump outlet. The vacuum pump comprises a stator with a static housing 72 and a rotor arranged in the housing 72 with a rotor shaft 12 rotatably mounted about a rotation axis 14.

The vacuum pump is embodied as a turbomolecular pump and comprises a plurality of turbomolecular pump stages which are pump-connected in series with a plurality of turbomolecular rotor disks 16 connected to the rotor shaft 12 and a plurality of turbomolecular stator disks 26 arranged in the axial direction between the rotor disks 16 and fixed in the housing 72 are held at a desired axial distance from each other. The rotor disks 16 and stator disks 26 provide in the scoop region 50 an axial pumping action directed in the direction of the arrow 58.

The vacuum pump also comprises three radially arranged pumping stages in series with one another, connected in series with each other. The rotor-side part of the Holweck pump stages comprises a rotor hub 74 connected to the rotor shaft 12 and two cylinder shell-shaped Holweck rotor sleeves 76, 78 fastened to and supported by the rotor hub 74, which are oriented coaxially with the axis of rotation 14 and are nested one inside the other in the radial direction. Furthermore, two cylindrical shell-shaped Holweck stator sleeves 80, 82 are provided, which are also oriented coaxially to the axis of rotation 14 and in radial Direction are nested in each other. The pump-active surfaces of the Holweck pump stages are each formed by the radial lateral surfaces opposite each other, forming a narrow radial Holweck gap, of a Holweck rotor sleeve 76, 78 and a Holweck stator sleeve 80, 82. In this case, one of the pump-active surfaces is in each case formed smoothly-in the present case that of the Holweck rotor sleeve 76 or 78 -and the opposite pump-active surface of the Holweck stator sleeve 80, 82 has a structuring with helically around the rotation axis 14 in the axial direction extending grooves, in which is driven by the rotation of the rotor, the gas and thereby pumped.

The rotatable mounting of the rotor shaft 12 is effected by a rolling bearing 84 in the region of the pump outlet and a permanent magnet bearing 86 in the region of the pump inlet 70.

The permanent magnet bearing 86 comprises a rotor-side bearing half 88 and a stator bearing half 90, each comprising a ring stack of a plurality of stacked in the axial direction of permanent magnetic rings 92, 94, wherein the magnetic rings 92, 94 opposite to form a radial bearing gap 96.

Within the magnetic bearing 86, an emergency or catch bearing 98 is provided, which is designed as an unlubricated roller bearing and runs empty in normal operation of the vacuum pump without touching and only with an excessive radial deflection of the rotor relative to the stator engages to a radial stop form for the rotor, which prevents a collision of the rotor-side structures with the stator-side structures.

In the area of the roller bearing 84, a conical spray nut 100 with an outer diameter increasing toward the rolling bearing 84 is provided on the rotor shaft 12, which is in sliding contact with at least one scraper of an accumulator containing a plurality of equipment, such as a lubricant, impregnated with absorbent pads 102. In operation, the resource is transferred by capillary action of the resource storage on the scraper on the rotating spray nut 100 and promoted due to the centrifugal force along the spray nut 100 in the direction of increasing outer diameter of the spray nut 100 to the rolling bearing 84 back, where there is, for example, a lubricating Function fulfilled.

The vacuum pump includes a drive motor 104 for rotationally driving the rotor whose rotor is formed by the rotor shaft 12. A control unit 106 controls the motor 104.

The turbomolecular pumping stages provide a pumping action in the direction of the arrow 58 in the scooping region 50. The following are based on the Fig. 2 to 7 in the vacuum pump of Fig. 1 implemented measures to prevent backflow of the gas against the conveying direction described. Corresponding components are in principle designated in all figures with the same reference numerals.

Fig. 2 shows the in Fig. 1 with the reference numeral A designated area with a rotor disk 16 and two adjacent stator disks 26 in detail.

Each rotor disk 16 has a plurality of blades 22 which are separated from one in Fig. 2 Not shown inner ring of the rotor disk 16 are supported. Between the outer radial ends of the blades 22 and the radially opposite spacer rings 36, a respective radial sealing gap 42 is formed.

The stator 26 has a plurality of blades 32, which of an outer ring 30 and a in Fig. 2 not shown inner ring are worn. The outer ring 30 of the stator 26 extends in the radial direction so far inward that it covers the sealing gap 42 of the preceding relative to the conveying direction rotor disk 16 in the axial direction and thus prevents backflow through the sealing gap 42. The region of the outer ring 30 which covers the sealing gap 42 thus forms a sealing section 34 for the sealing gap 42. The sealing section 34 is arranged next to the pump-active structure of the stator disk 26 formed by the blades 32, and thus prevents that in the region of the pump-active structure existing gas in the radial direction outwardly flows to the preceding in the conveying direction sealing gap 42 and further flows back through the sealing gap 42 against the conveying direction.

Instead, the gas is deflected inward in the radial direction by the sealing section 34, so that it encounters the pump-active structure formed by the blades 22 of the upstream rotor disk 16 after a possible return flow through the stator disk 26 and is pumped by these again in the conveying direction.

Fig. 3 to 5 show the in Fig. 2 shown stator 26 in detail. The stator 26 consists in the present embodiment of two semicircular parts 26 a, 26 b.

It is a nacelle, that is to say a stator disk 26 produced or to be produced from a sheet-like base body by deformation of the base body. Between the inner ring 28 and the outer ring 30 of the stator disk 26, the blades 32 of the stator disk are formed by punching and slitting the sheet-like base body 26 emerged. Fig. 3 and 4 show the stator 26 so far in an unfinished state, when the stator 26 is still in its undeformed planar state and the blades 32 are not yet brought by bending the body in its inclined position.

Fig. 5 shows the finished stator disk 26 after the spools 32 have been moved to their inclined position.

The outer ring 30 of the stator disc 26 with the sealing portion 34 forms a continuous closed annular surface, which covers the sealing gap 42 of the preceding in the conveying direction rotor disk 16 over preferably the entire circumference of the rotor disk 16 away.

Fig. 6 shows the in Fig. 1 designated by the reference B region of in Fig. 1 shown vacuum pump in detail. The rotor disk 16 has an extension 20 arranged at the outer radial ends of its blades 22 and projecting in the radial direction, which extends into a radial groove 38 of the spacer ring 36 adjacent to the rotor disk 16 in the radial direction and consisting of the two parts 36a, 36b extends into it.

By the extension 20 and the spacer ring 36, a radial sealing gap 44 is limited, to which on both sides in each case a limited by the extension 20 and the spacer ring 36 axial sealing gap 45 connects. The lower part 36b of the spacer ring 36 forms a sealing portion 40 which covers the radial sealing gap 44 and reduces a directed through the sealing gap 42 backflow. The extension 20 is formed in the present embodiment as over the entire circumference of the rotor disk 16 encircling and supported by the blades 22 of the rotor disk 16 closed ring. The radial division of the spacer ring 36 into the two parts 36a, 36b makes it possible to assemble the rotor disk 26 and the spacer ring 36 in spite of the axial undercut formed by the engagement of the extension 20 in the groove 38 in the axial direction.

Fig. 7 shows the in Fig. 1 designated by the reference numeral C range of in Fig. 1 shown vacuum pump in detail. The blades 22 of the rotor disks 16 and the blades 32 of the stator disks 16 arranged between the rotor disks 26 provide a pumping action for a gas present in the scooping region 50 in the direction of the arrow 58, while the inner ring 28 of the stator disk 26 with the inner rings 18 of the rotor disks 16 defines a sealing region comprising a radial sealing gap 46 and two axial sealing gaps 48.

Those opposing surfaces of the inner rings 18 of the rotor discs 16 and the inner ring 28 of the stator 26, each defining one of the axial sealing gaps 48, each form a Siegbahnpumpstufe, which provides a pumping action, which counteracts a backflow of the gas through the sealing area. For this purpose, the surfaces of the inner ring 28 of the stator disk 26 each have a structuring with a groove 52 running in the radial direction in the radial direction, in which the propelled gas is guided. The opposite surfaces of the inner rings 18 of the rotor disks 16 are smooth. By a backflow through the radial sealing gap 46 and the axial sealing gaps 48 opposite pumping action of the Siegbahnpumpstufen prevents the gas flows back past the blades 32 of the stator 26 through the sealing area, so that the pumping power of the vacuum pump is improved.

Fig. 8 shows a detail of a vacuum pump according to another embodiment of the invention in a sectional view. Fig. 9 shows the in Fig. 8 designated by the reference numeral D area in detail. In the 8 and 9 Apart from the specific features described in detail below, the vacuum pump shown in FIG Fig. 1 described vacuum pump.

The rotor disks 16 of in 8 and 9 Vacuum pump shown each comprise an inner ring 18 with a in the radial direction to the rotor shaft 12 towards widening collar portion 24 through which the rotor disks 16 are connected to the rotor shaft 12. The stator 26 has an inner ring 28 which has a radially projecting extension 35. Together, the inner ring 28 of the stator disc 26 and the inner rings 18 of the rotor discs 16 define two axial sealing gaps 49. The extension 35 of the inner ring 28 of the stator disc 26 and the collar portions 24 further define a radial sealing gap 47 connecting the axial sealing gaps 49, the V-shaped is formed and comprises two to the rotation axis 14 inclined portions 47a, 47b. Compared to a configuration which has no radial extension 35 and no radial sealing gap 46 extending obliquely to the axis of rotation 14 from the extension 35, but instead has an extended gap between the collar sections 24 and the inner ring 28, the backflow at the in 8 and 9 considerably reduced and the achievable pump power increased.

LIST OF REFERENCE NUMBERS

12

rotor shaft

14

axis of rotation

16

rotor disc

18

inner ring

20

extension

22

shovel

24

collar portion

26

stator

26a, 26b

Part of a stator disk

28

inner ring

30

outer ring

32

shovel

34

sealing portion

35

extension

36

spacer

36a, 36b

Part of a spacer

38

groove

40

sealing portion

42, 44, 46, 47

radial sealing gap

46a, 46b

Section sealing gap

45, 48, 49

axial sealing gap

50

adding area

52

groove

58

arrow

68

inlet flange

70

pump inlet

72

casing

74

rotor hub

76, 78

Holweck rotor sleeve

80, 82

Holweck stator

84

roller bearing

86

Permanent magnetic bearings

88

Rotor-side bearing half

90

stator side half

92, 94

permanent magnetic ring

96

radial bearing gap

98

safety bearing

100

spray mother

102

absorbent disc

104

drive motor

106

control unit

Claims (15)

Vacuum pump, in particular turbomolecular pump, - With a stator having a plurality of in the direction of a rotation axis (14) successive stator discs (26), each having a pump-active structure (32), and - With a relative to the stator about the rotation axis (14) rotatably mounted rotor comprising a rotor shaft (12) and a plurality on the rotor shaft (12) arranged in succession in the axial direction and between the stator disks (26) arranged rotor disks (16) each having a pump active structure (22), wherein at least one rotor disk (16) defines a radial sealing gap (42, 44) formed between the rotor disk (16) and the stator, and
wherein at least one stator-side sealing portion (34, 40) is provided which at least partially covers the sealing gap (42, 44) in the axial direction counter to the conveying direction and related to the conveying direction before and / or next to the pump-active structure (32) in the conveying direction on the rotor disc (16) following stator disc (26) is arranged. Vacuum pump according to claim 1,
characterized in that
the sealing section (34, 40) covers the sealing gap (42, 44) over its entire radial gap width. Vacuum pump according to claim 1 or 2,
characterized in that the stator disc (26) has a ring, in particular an outer ring (30), which carries the pump-active structure (32) of the stator disc (26), wherein the sealing portion (34) through the ring (30) of the stator disc (30). 26) is formed. Vacuum pump according to claim 1 or 2,
characterized in that the sealing portion (40) is formed by a spacer ring (36) holding two axially successive stator discs (26) at an axial distance from each other,
wherein in particular the sealing portion (40) defines a groove (38) which extends in the radial direction in the spacer ring (36), wherein the rotor disc (16) preferably engages in the groove (38). Vacuum pump according to claim 4,
characterized in that the spacer ring (36) is divided in such a radial direction, that the spacer ring (36) and the rotor disc (16) are assembled in the axial direction. Vacuum pump according to one of the preceding claims,
characterized in that the rotor disk (16) has at least one radial projection (20) which preferably protrudes radially from the pump-active structure (22) of the rotor disk (16), wherein the radial sealing gap (42, 44) at least in sections through the Extension (20) is limited. Vacuum pump, in particular turbomolecular pump, preferably according to one of the preceding claims, - With a stator having a plurality of in the direction of a rotation axis (14) successive stator discs (26), each having a pump-active structure (32), and - With a relative to the stator about the rotation axis (14) rotatably mounted rotor comprising a rotor shaft (12) and a plurality on the rotor shaft (12) arranged in succession in the axial direction and between the stator disks (26) arranged rotor disks (16) each having a pump active structure (22), wherein at least one stator disk (26) and / or at least one rotor disk (16) delimits a radial sealing gap (47) formed between the stator and the rotor, and
wherein the sealing gap (47) at least partially extends obliquely to the rotation axis (14). Vacuum pump according to claim 7,
characterized in that
a stator disk (26) delimiting the sealing gap (47) and / or a rotor disk (16) delimiting the sealing gap (47) has a ring, in particular an inner ring (18, 28), which has the pump-active structure (22, 32) of the respective one Washer (16, 26) carries, wherein at least a portion (47a, 47b) of the sealing gap (47), which extends obliquely to the axis of rotation (14) through the ring (28) of the stator (26) is limited and / or by the ring (18) of the rotor disc (16) is limited. Vacuum pump according to claim 8,
characterized in that a sealing gap (47) limiting ring, in particular an inner ring (18), the rotor disc (16) has an axially projecting collar portion (24), which is preferably connected to the rotor shaft (12), wherein at least one Section (47a, 47b) of the sealing gap (47) extending obliquely to the axis of rotation (14) is bounded by the collar portion (24). Vacuum pump according to claim 8 or 9,
characterized in that a sealing gap (47) delimiting ring (28), in particular the stator disc (26), a projecting in the radial direction extension (35), wherein at least a portion (47a, 47b) of the sealing gap (47) extends obliquely to the axis of rotation (14) is limited by the extension (35). Vacuum pump according to one of claims 7 to 10,
characterized in that the sealing gap (47) has at least two sections (47a, 47b) which run obliquely to the rotation axis (14) and at an angle to each other, preferably both sections (47a, 47b) each by a stator disc (26). on the one hand and one of two adjacent to the stator (26) rotor disks (16) on the other hand are limited. Vacuum pump, in particular turbomolecular pump, preferably according to one of the preceding claims, - With a stator having a plurality of in the direction of a rotation axis (14) successive stator discs (26), each having a pump-active structure (32), and - With a relative to the stator about the rotation axis (14) rotatably mounted rotor comprising a rotor shaft (12) and a plurality on the rotor shaft (12) arranged in succession in the axial direction and between the stator disks (26) arranged rotor disks (16) each having a pump active structure (22), the pump-active structures (32, 22) of the stator disks (26) and rotor disks (16) being designed to provide a pumping action oriented in a conveying direction for a gas present in a scooping region (50),
wherein a sealing region (46, 48) adjacent to the scooping region (50) is defined, which is at least partially bounded by a stator disk (26) and a rotor disk (16) adjacent to the stator disk (26), and
wherein opposing surfaces of the rotor and of the stator bounding the sealing region (46, 48) form at least one pumping stage for providing a pumping action for the gas present in the sealing region (46, 48), which causes a backflow of the gas through the sealing region (46, 46; 48) counteracts. Vacuum pump according to claim 12,
characterized in that the stator disc (26) has a ring, in particular an inner ring (28), which carries the pump-active structure (32) of the stator disc (26), and the rotor disc (16) has a ring, in particular an inner ring (18). comprising the pump-active structure (22) of the rotor disk (16), wherein the surfaces forming the pumping stage are formed by the rings (28, 18) of the stator disk (26) and the rotor disk (16). Vacuum pump according to claim 12 or 13,
characterized in that the pumping stage is a Siegbahnpumpstufe. Vacuum pump according to one of claims 12 to 14,
characterized in that at least one of the pumping stage forming surfaces extends obliquely to the axis of rotation (14).

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