EP2368043A1

EP2368043A1 - Vacuum pump

Info

Publication number: EP2368043A1
Application number: EP09768063A
Authority: EP
Inventors: Christian Beyer; Peter Klingner; Hans Kriechel
Original assignee: Oerlikon Leybold Vacuum GmbH
Current assignee: Leybold GmbH
Priority date: 2008-12-24
Filing date: 2009-12-09
Publication date: 2011-09-28
Also published as: DE102008063131A1; JP2012514149A; JP5579196B2; WO2010072568A1

Abstract

The invention relates to a vacuum pump, particularly a Holweck vacuum pump, comprising a pump housing (34), in which a rotor element (24, 36) is arranged. The rotor element comprises at least two tube-shaped conveying elements (24), which are arranged concentrically with each other and which are connected to a disk-shaped holding element (36). A stator element (26) is arranged between two adjacent conveying elements (24). According to the invention, a single helical channel (28) is formed by the stator element.

Description

vacuum pump

The invention relates to a vacuum pump, in particular a Hoiweck vacuum pump.

Vacuum pumps have a rotor element arranged in a pump housing. In a Holweck vacuum pump, for example, the rotor element has a tubular, arranged concentrically to the rotor shaft conveyor element. The conveying element is surrounded by a stator element, in which a helical channel is formed. Due to the rotation of the conveying element takes place due to the transport mechanism of Reibungsvakuumpumpen entrainment of the gas molecules to be delivered. The pointing in the direction of the stator element side of the conveying element transmits due to the rotational momentum pulses on the individual gas molecules. The performance of such a friction vacuum pump is essentially dependent on the relative speed between the friction surfaces and on the type of gas to be delivered.

A specially designed Holweck vacuum pump is described in DE 196 32 375. The rotor element of the Holweck vacuum pump described herein has a disk-shaped retaining member connected to the rotor shaft. Concentric with the rotor shaft, a plurality of tubular conveying elements are surrounded by the holding element. Adjacent conveying elements thus form an annular channel. Stator elements are arranged in these channels. Each stator element has a cylindrical, parallel to the conveyor elements extending, self-contained wall. On both sides of the wall, a helical web is arranged in each case, so that each stator element forms two helical conveying channels. Between two adjacent tubular conveying elements thus two conveying channels are formed. Here, a side wall of the conveying channel is always formed by the conveying element and the other three side walls of the conveying channel through the stator.

The object of the invention is to simplify the construction of a vacuum pump, in particular a Holweck vacuum pump, in particular to enable a more cost-effective production and / or to increase the delivery rate.

The object is achieved according to the invention by the features of claim 1.

The vacuum pump according to the invention, which is in particular a Holweck vacuum pump, has a rotor element arranged in a pump housing, which is preferably carried by a rotor shaft. The rotor element has at least two conveying elements, which are arranged concentrically with each other in a first preferred embodiment of the invention and tubular. In this embodiment, it is particularly preferred that the tubular conveying elements are also arranged concentrically to the rotor shaft. The conveying of the gas takes place here by the occurring at the side surfaces of the conveying elements friction, wherein the conveying elements exert pulses on the gas particles. Between two adjacent conveying elements, a stator element is formed. The stator element has a helical channel through which the medium is conveyed in the conveying direction. The conveying of the medium takes place by a Retativbewegung _ "5 _

between the stator element and the rotor element or the conveying elements of the rotor element. Here, usually, a rotation of the rotor element, which is connected to a rotor shaft. Likewise, however, can also erfofgen a rotation of the stator, wherein it is also possible in particular that both the stator and the rotor element are preferably rotated in the opposite direction.

According to the invention, the stator element has a single helical conveying channel.

Thus, in contrast to DE 196 32 375, not two but a single conveying channel are arranged between two adjacent conveying elements in the radial direction. The stator element thus has no central tubular wall which carries helical webs. In contrast, the stator element according to the invention is a preferably flat, helical band which is self-supporting. Possibly. At most Stabiiisierungsstege are provided by which, however, no separation into two separate channels.

According to the invention, a single helical channel is thus arranged in the radial direction between two adjacent conveyor elements. In the conveying direction or in the axial direction, it is possible to provide a plurality of mutually parallel channels, so that helical, multi-passage channels are provided.

Preferably, the two radial channel side surfaces are thus formed by two adjacent conveyor elements. The channel width in the radial direction thus preferably corresponds substantially to the distance between two adjacent conveying elements.

With the same cross-sectional area of the conveying channel, the embodiment of the conveying channels according to the invention has a higher conveying capacity, if so the other boundary conditions are identical. This can be seen from a comparison of the principles of FIGS. 1 and 2.

According to the prior art (FIG. 1), a delivery channel 10 is formed by a stator element 12, wherein three side surfaces 14, 16, 18 are formed by the stationary stator element. The fourth channel inner side 20 is formed by the rotating, tubular conveying element 22. Perpendicular to the plane of the drawing, the velocity distribution v shown in principle under the sketch thus results. In a simplified way, i. without consideration of the "slip flow" condition, the velocity distribution is substantially linear, as shown in the diagram The velocity is maximal at the inside 16 of the delivery channel and at the inside 20 of the delivery element 22. This corresponds essentially to the tangential one Speed of the Rotating Conveying Element 22 Provided that the compression K = I, the volume of gas delivered is proportional to the area and the integral over the speed.

According to the first preferred embodiment of the invention, two concentric tubular conveying elements 24 are provided. Between the two conveying elements 24, the helical stator element 26 is arranged. A conveying channel 28 is thus formed on the one hand by the two stationary inner walls 30 of the stator element 26 and the two moving inner walls 32 of the conveying elements 24. As shown in the diagram in FIG. 2, the velocity distribution v perpendicular to the drawing plane is such that the velocity at the two inner walls 32 is maximum. In a simplified way, the velocity distribution is again linear, so that the area under the curve, in simplified terms, is twice as large as the area under the velocity distribution according to the prior art.

Dashed lines show in the two diagrams the somewhat less simplified speed curves. It can be seen, however, that the delivery volume (area under the curve) in the embodiment according to the invention (FIG. 2) is considerably larger than in the embodiment according to the prior art (FIG. 1),

In a preferred embodiment, the rotor element has a particular disk-shaped, connected to the rotor shaft holding member. The at least two tubular conveying elements are connected to the holding element. In this case, it is preferable for the retaining element to have, in particular, annular projections onto which the conveying elements can be plugged or inserted. The connection can be made by a press fit, gluing or dgi.

Preferably, the conveying elements are arranged only on one side of the holding element, wherein it is particularly preferred that the holding element is arranged in the conveying direction in front of the conveying elements. This has the advantage that the holding element can additionally have rotor blades, through which the gas to be pumped is conveyed in the direction of the conveyor elements.

In order to be able to realize a compact vacuum pump as possible, it is advantageous that an additional conveying channel is arranged between an outer conveying element and an inner wall of the pump housing. Here, the corresponding additional stator element may be directly connected to the pump housing or formed integrally with the pump housing.

Furthermore, the inner conveyor element can be replaced directly by the outside of the rotor shaft.

In a particularly preferred embodiment, the conveyor elements and / or the holding element, ie preferably the entire rotor element, are made of a light and at the same time high-strength material. In particular, it is possible to manufacture the components from plastic, preferably from CFRP. - S -

As a result, the production costs can be significantly reduced. Furthermore, the use of such lightweight components has the advantage that the moment of inertia occurring are considerably lower. The construction of the bearings, which are in particular magnetic bearings, can thus be simplified. This results in a further cost reduction.

According to a second preferred Ausführuπgsforrn the invention disc-shaped conveying elements are provided instead of tubular conveying elements. These at least two disk-shaped conveying elements are preferably arranged substantially parallel to one another and extend in a particularly preferred embodiment substantially radially to the rotor shaft. According to the first preferred embodiment, a stator element is arranged between two adjacent conveying elements, which has a single helical channel, which in turn can be designed to be more continuous. The conveying principle corresponds to the conveying principle described with reference to the first embodiment, wherein the conveying of the gas takes place essentially in the radial direction. It is particularly preferred that the rotor shaft has a preferably axially extending conveyor channel or is formed as a hollow shaft. In this case, the conveying of the gas can take place, for example, such that the gas is sucked in through the channel formed by the rotor shaft and transported radially outwardly through the spiral channels arranged between adjacent conveying elements. Likewise, a reverse conveying direction is possible. Furthermore, it is possible, for example, for the gas to be conveyed from adjacent delivery channels, in particular alternately radially inwards and outwards, so that a serpentine-line delivery stream is formed in cross-section.

The conveying of the fluid, which is usually a gaseous fluid, is effected due to the relative movement between the rotor element and the stator element. In particular, this is the relative movement between the conveying elements of the rotor element relative to the Statoreiernent. In a preferred embodiment, the stator element is stationary or stationary, so that only a driving of the rotor element takes place via the rotor shaft.

However, it is also possible to configure the component described as rotor element in the embodiments described above stationary or stationary and to drive the helical or spiral channels forming stator by being connected for example to a drive shaft.

Furthermore, it is possible for both the rotor elements and the stator elements to be driven and, for example, to be connected to a corresponding drive shaft. By oppositely rotating the Rotoreiemente to the Statoreiementen creates a relative movement through which the fluid is conveyed.

The invention will be explained in more detail with reference to a preferred embodiment with reference to the accompanying drawings.

Show it:

Fig. 1 is a schematic schematic representation of a detail of a

Vacuum pump according to the prior art,

Fig. 2 is a schematic schematic representation of a detail of a

Vacuum pump according to a first preferred embodiment of the invention,

3 is a schematic, perspective sectional view of a Holweck

Stage of a vacuum pump according to the invention according to the first preferred embodiment of the invention, 4 is a schematic perspective view of a Statoreiements according to the first preferred embodiment of the invention,

Fig. 5 is a schematic sectional view of a second preferred

Embodiment of the invention, and

Fig. 6 is a schematic sectional view of a spiral-shaped

Statoreiements.

In a pump housing 34 (FIG. 3), the rotor element designed according to the invention is arranged. This has a substantially disk-shaped holding element 36. The holding element 36 is connected via a central pin 38 with a rotor shaft, not shown. For clarity, the center line 58 of the rotor shaft is shown. The inner region of the disk-shaped holding element 36 is designed as a closed disk 40. This is followed by radially extending rotor blades 42. Arranged on an underside of the holding element 36, which faces in a conveying direction 44, are annular projections 46, which are preferably formed integrally with the holding element 36.

With the annular lugs 46 three tubular or kreisrϊngzylindrisch trained conveying elements 24 are firmly connected by plugging in the illustrated embodiment. Rotation of the holding element 36 thus likewise causes the tubular conveying elements 24 to rotate. Between two adjacent conveying elements 24 there is respectively arranged a stator element 26 designed according to the invention, two stator elements 26 being provided in the exemplary embodiment shown.

The stator elements 26 are, as can be seen in particular from FIG. 4, formed in a screw-like manner. This may be a single helical element or a plurality of helical elements arranged one inside the other. The illustrated in Fig. 4 _Q_

Ausfuhrungsbeispie! a Statorelements 26 has a total of five interlocking, each formed as a part-helical element Statorteiie 52. Between each adjacent stator 52, a helical channel is formed in each case, wherein the provision of a plurality of interlocking stator 52 are provided a plurality of conveying channels in the conveying direction or axially parallel to each other. The operation of the individual delivery channels 28 is shown in FIG. 2.

The stator element 26 shown in FIG. 4 thus has a plurality of conveying channels 28 running parallel to one another in the axial direction or in the conveying direction 44. In the radial direction, however, no intersection of the delivery channels 28 is provided, so that, as described with reference to FIG. 2, a significantly larger, substantially double delivery volume can be achieved.

In the illustrated embodiment (FIG. 3), an additional delivery channel 48 is provided between the outer delivery element 24 and the pump housing 34. This is formed by a likewise helically formed additional stator element 50, wherein the additional stator 50 in the illustrated Ausführungsbeispie! is fixedly connected to an inner wall 54 of the housing or formed integrally with the housing 34.

The conveyed through the individual conveyor channels 28, 48 medium is ejected through openings 56 and fed to another conveyor stage. It is also possible to provide for adjacent conveyor channels 28, 48 common ejection openings.

In a second preferred embodiment (FIG. 5), in principle the conveying principle according to the invention explained with reference to FIG. 2 is also realized. However, the conveying of the gas, relative to a longitudinal axis 58 of a rotor shaft 60, takes place in the radial direction. Within a schematically illustrated housing 62, a rotor groove 60 formed as a hollow shaft in the illustrated embodiment is arranged. With the hollow shaft 60 disc-shaped conveyor elements 64 are connected. The conveying elements 64 surrounding the rotor shaft 60 can in this case be fixed by means of lugs 66, which are of annular design and are connected to an outer side of the hollow shaft 60. Between two adjacent disc-shaped conveying elements 64 of the conveying channel 28 is formed. Within the conveying channel 28, a Statoreiement 68 is arranged. In the second preferred embodiment (FIG. 5), this is not helical but spiral-shaped, so that the channel is also helical and extends radially. The gas is thus within the channel 28 in the embodiment shown in Fig. 5 spiral, for example, from the inside out, promoted.

In the preferred embodiment of the second embodiment according to the invention shown in FIG. 5, the medium to be conveyed is drawn through an inlet opening 70 of the housing 62 in the direction of an arrow 72, so that the medium enters an internal space 74 of the hollow shaft 60. From the interior 74, the gas through openings 76 in the hollow shaft 60, as shown by the arrows, conveyed into the channels 28. Through an outlet opening 78 of the housing, an ejection of the gas takes place in the direction of an arrow 81,

On inner walls 80 of the housing 62 are in the illustrated embodiment, in particular fixed to the housing 62 connected or integrally formed therewith additional stator 82, so that also takes place between the two outer disc-shaped conveying elements 64 and the inner wall 80 of the housing 62, a conveying of the gas ,

The hollow shaft 60 is supported by a shaft 86 connected to a drive device 84. The stator element 68 is formed spirally. As a result, by the stator element 68, a single, in Fig. 5, for example, from the inside to the outside extending channel may be formed. It is also possible to form the spiral stator element 68, as illustrated schematically in FIG. 6 as a sectional view. The spiral-shaped stator element 68 shown here is designed to be more continuous, wherein in the embodiment shown, three channels 88 are formed, which run parallel to one another. The channel inlets are arranged regularly in the illustrated embodiment, the Kanaleiniässe are offset at three channels in each case by 120 ° to each other.

Claims

claims

1. Vacuum pump, in particular Holweck vacuum pump, with

a rotor element (36, 24, 64) arranged in a pump housing (34, 62) and connected to a rotor shaft (58), which has at least two conveying elements (24, 64), and

a stator element (26, 68) arranged between two adjacent conveying elements (24, 64),

the stator element (26, 68) having a single helical or spiral channel (28),

d a d u r c h e c e n c i n e s that

the rotor shaft (58) is formed as Hohlweile (60), so that the gas to be conveyed is at least partially supported by the hollow shaft (60).

2. Vacuum pump according to claim 1, characterized in that the conveying elements (64) are disc-shaped and arranged substantially parallel to each other.

3. Vacuum pump according to claim 2, characterized in that the conveying elements (64) extend substantially radially to the rotor shaft (58). , Vacuum pump according to one of claims 1 to 3, characterized in that the two axial channel side surfaces (65) of the spiral channel (28) by two adjacent conveying elements (64) are formed. , Vacuum pump according to one of claims 1 to 4, characterized in that the channel width corresponds to the distance between two adjacent conveying elements (24, 64). , Vacuum pump according to one of claims 1 to 5, characterized in that the rotor element (36) has a particular disc-shaped, with the rotor shaft connected holding element (36), with which the conveying elements (24) are connected. , Vacuum pump according to claim 6, characterized in that the holding element (36) in particular annular projections (46), with which the conveying elements (24) are connected by insertion or plugging, vacuum pump according to claim 6 or 7, characterized in that the holding element (36) is arranged in the conveying direction (44) in front of the conveying elements (24) and preferably has rotor wings (42) for conveying a gas in the direction of the conveying elements (24).

9. Vacuum pump according to one of claims 1 to 8, characterized in that a plurality, in particular at least two concentrically arranged conveying elements (24) are provided, wherein between the conveying elements (24) each have a Statoreiement (26) each having a single helical conveying channel ( 28) is arranged.

10. Vacuum pump according to one of claims 1 to 9, characterized by an additional Förderkanai (48) which is arranged between an outer conveying element (24) and an inner wall (54) of the pump housing (34), wherein the corresponding additional stator element (48). 50) is preferably connected to the pump housing (34).

11. Vacuum pump according to one of claims 1 to 10, characterized in that the holding element (36) and / or the conveying elements (24) and / or the hollow shaft (60) are made of CFRP.

12. Vacuum pump according to one of claims 1 to 11, characterized in that the Statoreiement (26, 68) has a single multi-start, helical or spiral channel (28).

13. Vacuum pump according to one of claims 1 to 12, characterized in that a conveying of the conveying medium in the channel (28) due to a relative movement between the rotor element (36, 24, 64) and stator element (26, 68).

14. Vacuum pump according to one of claims 1 to 13, characterized in that the rotor element is supported by a preferably driven by an electric motor rotor shaft (58) and the stator element (26, 68) is preferably stationary.