EP3447299A1 - Adjusting ring - Google Patents

Abstract

The invention relates to an adjusting ring with an adjusting portion for the axial alignment of a radially inner first bearing portion of a bearing of a vacuum pump, in particular turbomolecular pump, in the direction of a longitudinal center axis of the bearing relative to a radially outer second bearing portion of the bearing of the vacuum pump, characterized in that a circumferential Collar emerges from the adjusting portion of the adjusting ring, which has a radially outwardly extending radial collar portion. Furthermore, the invention is directed to a bearing for a vacuum pump with such a bearing and to a vacuum pump with such a bearing.

Description

The present invention relates to an adjusting ring with an adjusting portion for axially aligning a radially inner first bearing portion of a bearing of a vacuum pump, in particular turbomolecular pump, in the direction of a longitudinal center axis of the bearing relative to a radially outer second bearing portion of the bearing of the vacuum pump.

Such an adjustment ring for a bearing of a vacuum pump is basically known. The bearing serves to support a relative to a stator about a rotation axis rotatable rotor of the vacuum pump and usually consists of two bearing portions, of which one is disposed radially within the other. A bearing section here is assigned to the stator and the other bearing section to the rotor. Radially between the bearing sections is a gap, which is also referred to as a bearing gap.

Undesirable foreign bodies, e.g. Particles can get into the space over time and settle there, which can lead to increased friction between the bearing sections and a consequent higher power consumption and premature wear of the bearing and worst case to a total failure of the vacuum pump.

For high vacuum applications, the storage of the rotor on the vacuum side primarily uses lubricant-free bearings, such as magnetic bearings, in order to avoid contamination of a recipient to be evacuated with lubricant. A magnetic bearing comprises at least one pair of magnets, in particular Permanent magnets, wherein the stator-side bearing portion and the rotor-side bearing portions each comprise a magnet of the magnet pair.

The magnets of the magnetic bearing generate a static stray magnetic field both during standstill of the vacuum pump and dynamic, i.e., in the operation of the vacuum pump. time-varying, magnetic stray field, which additionally superimposes the static magnetic stray field. The dynamic stray magnetic field is emitted essentially at the rotational frequency of the rotor and is due to unavoidable production-related locally occurring variances in the magnetic field strength and field alignment of the magnets of the rotor-side bearing section.

The static and / or dynamic stray magnetic field may impair high-sensitivity applications, for example, by deflecting an electron beam of an electron microscope due to the Lorentz force, which may lead to aberrations or a reduction in the resolution of the electron microscope. Also, the stray magnetic field may affect the magnetization of a vacuum-deposited high-sensitivity magnetic thin film.

Also, during operation of the vacuum pump in an environment with, in particular strong, magnetic field sources, eddy currents can be induced in the rotating rotor. The eddy currents lead to a deceleration of the rotor, so that an increased power requirement is necessary to maintain a certain rotor speed. Moreover, the eddy currents cause heating of the rotor, which can significantly reduce the bearing gap due to thermal expansion. In the worst case, the thermal expansion of the rotor can be so strong that the rotor, in particular with a small gap of the bearing gap, comes into contact with the stator and is consequently braked. The vacuum pump can come to a complete standstill or even be damaged.

An object of the invention is to provide a way to protect a bearing gap from contamination and a magnetic field shield.

The object is achieved by an adjusting ring with the features of claim 1 and in particular by the fact that a circumferential collar emerges from the adjusting portion of the adjusting ring, which has a radially outwardly extending radial collar portion.

The invention is based on the general idea of an already existing adjustment for the axial alignment of a first bearing portion relative to a second bearing portion of a bearing to a protective function of a bearing gap between the bearing portions from contamination, i. prior to deposition of debris, by providing the adjustment ring with a circumferential collar which emerges from an adjustment portion of the adjustment ring and which has a radially outwardly extending radial collar portion. As a result, at most still reaches a minimum, especially harmless, amount of foreign bodies in the bearing gap, at best, the penetration of foreign bodies is completely suppressed in the bearing gap. This results in the advantage of a longer life of the bearing and a lower power consumption, since due to the reduced number of foreign bodies between the bearing sections less friction arises. A further advantage is that with the aid of the radial collar portion of the adjusting ring at least partially and at best complete magnetic shielding of the rotor from external magnetic fields and / or vice versa protection of magnetically sensitive applications in front of a stray magnetic field of a magnetic bearing used for storage is possible.

Under the axial orientation of the one bearing portion with respect to the other bearing portion is in this context an orientation of the two bearing sections to understand each other in the direction of the longitudinal center axis of the bearing. In particular, the longitudinal central axis of the bearing may correspond to the axis of rotation of the rotor.

It should be noted that the adjustment is not limited to the application in vacuum pumps, but in principle can be used wherever it takes an axial alignment of two bearing sections of a bearing and protection from contamination or a shielding of magnetic fields is desirable.

Advantageous embodiments of the invention are described in the dependent claims, the description and the drawings.

The adjusting ring may have an at least approximately circular peripheral profile and be made of a round steel, in particular a stainless steel round bar, by a machining process, such as turning or milling. Here, the adjusting ring is preferably made of one piece, so that the adjusting portion and collar of the adjusting ring are integrally formed. But it is also conceivable that the adjusting section and the collar are separate components which are joined together to form the adjusting ring, for example by shrinking, gluing, soldering, welding or the like. Moreover, it is also conceivable that the adjusting portion and the radial collar portion are separate and joined to form the adjusting components.

The adjustment ring may not only have an at least approximately circular peripheral profile, but also any other circumferential profile, such as a polygonal circumferential profile. In this case, a hexagonal circumferential profile may be particularly favorable, as a result of which the adjusting ring can be rotated in a particularly simple manner by means of a tool, in particular by means of an open-end wrench.

It is understood that the adjusting ring can be made not only of a round steel but also of any other metallic material or other suitable material, for example of a plastic or a ceramic. In addition, the adjustment portion and the collar may be made of different materials. Furthermore, it is also conceivable that the adjustment section and / or the radial collar section may consist of different materials.

For even better magnetic shielding of the rotor relative to external magnetic fields and / or the environment of the vacuum pump relative to a magnetic bearing field generated by a magnetic bearing for supporting the rotor magnetic field or magnetic field, it is advantageous if the setting at least partially a ferromagnetic, especially soft magnetic, and / or comprising electrically conductive material.

With the help of the ferromagnetic material both static and dynamic magnetic fields can be reliably shielded. The ferromagnetic material is characterized by a relative magnetic permeability that is significantly greater than 1. Preferably, the ferromagnetic material comprises at least one of iron (Fe), nickel (Ni), cobalt (Co), or an alloy of at least two of these metals , Moreover, alloys of aluminum / nickel / cobalt (Al / Ni / Co) or samarium / cobalt (Sm / Co) are conceivable. Instead of the ferromagnetic material but also a ferrimagnetic ceramic material may be used, such as a ferrite. In general, the higher the magnetic permeability of the material making up the adjustment ring, the better the magnetic shielding.

Additionally or alternatively, the adjusting ring may comprise an electrically conductive, in particular a diamagnetic or paramagnetic, material, such as Example copper, aluminum, non-ferromagnetic alloys of copper and / or aluminum or non-ferromagnetic steels.

When using an electrically conductive, in particular non-ferromagnetic, material, the advantage lies in the fact that the dynamic magnetic fields generated by the rotating rotor and mainly disturbing for magnetically sensitive applications can be shielded particularly effectively. The magnetic shield is based on induction effects, which are caused in the electrically conductive material by the alternating magnetic field and which are dependent on the frequency of the dynamic magnetic field or alternating magnetic field and the specific internal electrical resistance of the electrically conductive material. Another advantage of using electrically conductive, in particular non-ferromagnetic, materials is that more and / or more cost-effective and / or more resistant to the gases to be pumped materials are available compared to ferromagnetic materials.

It should also be noted that the magnetically shielding effect of the adjusting ring makes it possible at best to dispense with additional magnetic shielding, so that a number of components can be reduced and / or material and manufacturing costs can be saved.

In order to improve the protective function against impurities and / or the shielding against magnetic fields, the adjusting ring may further comprise an axial collar portion, which projects at an angle from the radial collar portion. In principle, the adjustment section and / or the radial collar section and / or the axial collar section can consist of different materials. It is understood that the adjusting portion and the radial and axial collar portion but can also be integrally formed with each other. Alternatively, the adjustment portion and / or the radial collar portion and / or the axial collar portion be separate and joined to form the adjustment components.

The axial collar section preferably emerges from this at a radially outer edge region of the radial collar section.

In order to pretension and / or fix the stator-side bearing section in the axial direction, a spring element can be arranged in the axial direction between the adjusting section of the adjusting ring and the stator-side bearing section of the bearing. It is also conceivable that the adjusting portion for the purpose of axial prestressing and / or fixing of the stator-side bearing portion may have a plurality of stacked in the axial direction components, viewed in the axial direction between at least two components of the adjusting portion forming stack of components at least one spring element may be arranged can. It will be appreciated that the radial collar portion may emerge from one of the components of the stack.

If the adjustment section comprises at least two components stacked axially one above the other and if one of the components shows the radial collar section, then the or each component of the adjustment section without radial collar section and the component with radial collar section can be rotated relative to one another. In this case, the radial collar section may have at least one bore penetrating the radial collar section, so that the or each component of the adjustment section is freely accessible without a radial collar section. As a result, the or each component of the adjustment without radial collar portion, for example by means of a tool rotate relative to the component with radial collar portion to align by rotation of the or each component without collar portion the stator bearing portion in the axial direction with respect to the rotor-side bearing portion. Basically, the components of the adjustment section with and Without radial collar portion also connected to each other, in particular rotatably connected to each other, be that a rotation of the radial and / or axial collar portion causes a rotation of the or each component of the adjustment section without radial collar portion.

The protective function against impurities and / or the shielding against magnetic fields can be improved even further by the adjusting ring having, in addition to the radial collar section and / or axial collar section just described, further radial and / or axial collar sections. Preferably, at least one further radial collar portion and / or a further axial collar portion protrude from the aforementioned radial or axial collar portion. Advantageously, several radial and axial collar sections alternate. In this case, a plurality of radial and axial collar portions may alternate such that the entirety of the collar portions seen in cross-section has a rectangular modulation. Also, a step-like modulation of several radial and axial collar sections is conceivable. Moreover, from a radial collar portion, two axial collar portions may be angled such that the two axial collar portions face in opposite directions, ie, the radial collar portion and the two axial portions substantially correspond to T or Y tilted by about 90 ° also emerge from an axial collar portion two radial collar sections. In particular, the adjusting ring may have a circumferential collar which emerges from an adjusting portion of the adjusting ring, wherein the circumferential collar has a radially outwardly extending first radial collar portion and resulting therefrom an angled axial collar portion and a second radial collar portion radially extending the first radial collar portion extended to the outside. Such an adjustment ring has, viewed in cross-section, as it were, a T-shaped collar. The advantage of a so configured adjustment ring is in a stronger magnetic Shielding by the first and second radial collar portion and a better protection against contamination by the axial and first radial collar portion.

According to an advantageous embodiment, the radial collar portion has a smaller axial dimension than the adjustment portion, i. the radial collar portion is seen in the direction of the longitudinal center axis of the bearing thinner than the adjustment portion. Additionally or alternatively, the axial collar portion and the adjustment portion may have at least approximately equal axial dimensions, or in other words, the adjustment portion and the axial collar portion seen in the direction of the longitudinal center axis of the bearing at least approximately the same length. It is understood that the adjustment section and the axial section can in principle also have different axial dimensions. If the adjusting ring comprises a plurality of radial and / or axial collar sections, the axial dimensions of all radial collar sections and / or of all axial collar sections can be at least approximately the same. It is understood, however, that at least two radial and / or two axial collar sections may also have different axial dimensions.

The invention also relates to a bearing for a vacuum pump, in particular turbomolecular pump, with a radially inner first bearing portion, a radially outer second bearing portion and an adjusting ring, which serves for the axial alignment of the first bearing portion relative to the second bearing portion in the direction of the longitudinal center axis of the bearing , The bearing according to the invention is characterized in that the radially extending collar portion spans the second bearing portion in the radial direction. If the adjusting ring has an axial collar portion, the second bearing portion is arranged in the radial direction between the adjusting portion and the axial collar portion of the adjusting ring.

A particularly good protective effect against undesired deposition of foreign bodies in the bearing gap can be achieved if the axial collar portion partially overlaps axially with the second bearing portion.

According to an advantageous embodiment, the bearing comprises a locking ring for locking the second bearing portion, which is arranged in the radial direction at least in sections between the adjusting portion and the axial collar portion.

The protective effect of the adjusting ring can be further increased if the locking ring defines together with the adjusting ring an annular gap with multi-angled cross-section. The annular gap forms a sort of labyrinth, in which foreign bodies can get caught before they reach the bearing gap.

It should be noted at this point that the or each radial collar portion and / or the or each axial collar portion of the adjusting ring can be configured such that together with the adjusting ring or the second bearing portion spanned by a radial portion in the radial direction achieves a pumping action becomes. For example, at least one of the collar sections may have groove-like, in particular spiral groove-like, structures which, together with the locking ring or the second bearing section spanned by the adjusting ring, form a pumping system based on the Holweck and / or Siegbahn pumping principle. Preferably, the pumping action of such a pumping system is such that the gas delivery direction is directed away from the bearing gap, so as to oppose an undesirable foreign body counterflow, so that the foreign body can not get into the bearing gap or at least a penetration of the foreign body is difficult in the bearing gap.

According to a preferred embodiment, the bearing is a magnetic bearing, wherein the first and second bearing portion each comprises at least one magnet. The magnet may be a permanent magnet, in particular a monolithic permanent magnet.

Furthermore, the invention is directed to a vacuum pump with a rotatably mounted relative to a stator rotor and a bearing for supporting the rotor on the stator, wherein the stator is preferably arranged radially inside the rotor.

For axial alignment of the stator-side bearing section with respect to the rotor-side bearing section, the adjusting ring can be threadedly engaged with the stator so that the stator-side bearing section can be axially aligned by rotation of the adjusting ring about the longitudinal central axis of the bearing with respect to the rotor-side bearing section. For this purpose, the stator and the adjusting ring have a complementary thread to each other, with a particularly accurate alignment of statorseitigem and rotorseitigem bearing section can be achieved by a fine thread.

Fig. 1

eine Querschnittsansicht einer Turbomolekularpumpe mit einem nicht erfindungsgemäßen Einstellring; und

Fig. 2

eine Detailansicht der Turbomolekularpumpe von Fig. 1 mit einem erfindungsgemäßen Einstellring.

The invention will now be described purely by way of example with reference to a possible embodiment with reference to the accompanying drawings. Show it:

Fig. 1

a cross-sectional view of a turbomolecular pump with a not inventive adjustment ring; and

Fig. 2

a detailed view of the turbomolecular pump of Fig. 1 with an adjustment ring according to the invention.

In the Fig. 1 shown turbomolecular pump 10 comprises a pump inlet 14 surrounded by an inlet flange 12 and a plurality of pumping stages for conveying the gas present at the pump inlet 14 to a in Fig. 1 not shown pump outlet. In a housing 16 of the turbomolecular pump 10, a rotatable relative to a stator 17 rotor 18 with a about a rotational axis 20 rotatably mounted rotor shaft 22 is arranged, wherein the stator 17 is located radially inside the rotor 18.

To generate a pumping action, the turbomolecular pump 10 comprises a plurality of pump-effectively connected in series turbomolecular pumping stages with a plurality of attached to the rotor shaft 22 rotor disks 24 and in the axial direction between the rotor disks 24 stator 26th The stator 26 are by spacer rings 28 at a desired axial distance from one another held.

Furthermore, three Holweckpumpstufen arranged one inside the other in the radial direction and pump-connected in series with one another are provided. The rotor-side part of the Holweckpumpstufen comprises a rotor shaft connected to the rotor hub 30 and two fixed to the rotor hub 30 and carried by this cylinder jacket Holweckrotorhülsen 32, 34, which are coaxial with the axis of rotation 20 oriented and nested in the radial direction. Furthermore, two cylinder jacket-shaped Holweckstatorhülsen 36, 38 are provided, which are also coaxial with the axis of rotation 20 oriented and nested in the radial direction.

The pump-active surfaces of the Holweckpumpstufen are each formed by each other with the formation of a narrow radial Holweckspalts radial lateral surfaces of a Holweckrotorhülse 32, 34 and a Holweckstatorhülse 36, 38. In each case, one of the pump-active surfaces is smooth - mainly that of Holweckrotorhülse 32, 34 - and the opposite pump-active surface of Holweckstatorhülse 36, 38 has a structuring with helically around the rotation axis 20 in the axial direction extending grooves, in which the rotation of the rotor 18, the gas is propelled and thereby pumped.

The rotatable mounting of the rotor shaft 22 is effected by a roller bearing 40 in the region of the pump outlet and in the region of the pump inlet 14 by a bearing 42, which is formed in the illustrated embodiment as a permanent magnet bearing 42.

The permanent magnet bearing 42 comprises a rotor-side bearing portion 44 and a stator-side bearing portion 46, each having a ring stack of a plurality of in the axial direction, i. in the direction of a longitudinal central axis 47 of the permanent magnet bearing 42, stacked permanent magnetic rings 48, 50, wherein the magnetic rings 48, 50 opposite to form a radial bearing gap 52. As can be seen from the figures, the longitudinal central axis 47 of the permanent magnet bearing 42 and the axis of rotation 20 of the rotor 18 coincide.

The stator-side bearing portion 46 forms a first bearing portion 46 of the bearing 42, which is arranged radially within the rotor-side bearing portion 44 (second bearing portion 44). For axial alignment of the stator-side bearing portion 46 with respect to the rotor-side bearing portion 44 is provided with the stator 17 in threaded engagement adjusting ring 53. In this case, the stator-side bearing section 46 can be axially aligned with respect to the rotor-side bearing section 44 by rotation of the adjusting ring 53 about the axis of rotation 20. At the in Fig. 1 shown adjustment ring 53 is a conventional adjustment ring 53, which is inventively replaced by an adjustment ring 84, as it is based on Fig. 2 will be described.

A rotation of the adjusting ring 53 such that the stator-side bearing portion 46 is axially displaced in the direction of the located in the pump outlet 40, causes axial displacement of the stator bearing portion 46 against the restoring force of a spring element 51, which is formed here by a plurality of stacked disc springs. The spring element 51 may, however, also be, for example, a helical compression spring or any other spring element which, in the described rotation of the adjusting ring 53, opposes a restoring force to the stator-side bearing section 46 axially displaced axially in the direction of the rolling bearing 40.

The rotor-side bearing portion 44 is held by a locking ring 55 on the rotor 18. The locking ring 55 has a holding portion 57 a for holding the magnetic rings 50 of the rotor-side bearing portion 44 on the rotor 18. The holding portion 57 a is connected to a radially outwardly extending attachment portion 57 c of the locking ring 55 by means of a radially outwardly extending intermediate portion 57 b. The attachment portion 57c is seen in the circumferential direction with several extending in the radial direction bores 59, which serve not shown locking screws for mounting the locking ring 55 on the rotor 18. Unlike the one in Fig. 1 shown locking ring 55 has the in Fig. 2 Locking ring 55 shown one out of the holding portion 57 a and extending radially outwardly and axially angled in the direction of the rolling bearing 40 intermediate portion 57 b, which in turn merges into the radially outwardly extending mounting portion 57 c.

Coming back on again Fig. 1 an emergency or fishing camp 54 is provided within the magnetic bearing 42, which is designed as an unlubricated roller bearing and idles in normal operation of the turbomolecular pump 10 without contact and only with an excessive radial deflection of the rotor 18 with respect to the stator engages to a radial Stop for the rotor 18, which prevents a collision of the rotor-side structures with the stator-side structures. The emergency bearing 54 thus defines the maximum radial deflection of the rotor 18th

In the region of the roller bearing 40, a conical injection nut 56 with an outer diameter increasing towards the rolling bearing 40 is provided on the rotor shaft 22. The spray nut 56 is in sliding contact with at least one wiper of a plurality of stacked absorbent disks 58 having an operating means such as e.g. a lubricant for the rolling bearing 40 are soaked.

In operation of the turbomolecular pump 10, the resource is transmitted by capillary action of the resource storage on the wiper on the rotating spray nut 56 and due to the centrifugal force along the spray nut in the direction of increasing outer diameter of the spray nut 56 to the rolling bearing 40 promoted towards where it for example fulfills a lubricating function.

Turbomolecular pump 10 includes an engine compartment 60 into which rotor shaft 22 extends. The engine compartment 60 is sealed in the region of the entry of the rotor shaft 22 by a victory track 62 with respect to a working or suction chamber of the turbomolecular pump 10. A barrier gas inlet 64 allows delivery of a barrier gas into the engine compartment 60.

In the engine compartment 60, a drive motor 66 is arranged, which serves for the rotational driving of the rotor 18. The drive motor 66 comprises a motor stator 68 with a core 70 and with several in Fig. 1 only schematically illustrated coils 72 which are defined in provided on the radially inner side of the core 70 grooves of the core 70. The core 70 consists of a laminated core with several in the axial direction stacked sheet metal discs made of a soft magnetic material.

The rotor of the drive motor 77, which is also referred to as an armature, is formed by the rotor shaft 22, which extends through the motor stator 68 therethrough. On the extending through the motor stator 68 through portion of the rotor shaft 22, a permanent magnet assembly 74 is fixed radially on the outside. Between the motor stator 68 and the section of the rotor shaft 22 extending through the motor stator 68, a radial motor gap 76 is formed, via which the motor stator 68 and the permanent magnet arrangement 74 influence magnetically for transmission of the drive torque.

The permanent magnet assembly 74 is fixed to the rotor shaft 22 by means of gluing and / or shrinking and / or pressing. The permanent magnet arrangement 74 comprises a soft-magnetic yoke 75a made of iron sheets or solid iron and a permanent magnet 75b. An encapsulation 80, which is designed as a CFK or stainless steel sleeve, surrounds the permanent magnet arrangement 74 on its radial outer side and seals it against the motor gap 76. On the rotor shaft 22, a balancing ring 78 is further attached by gluing and / or shrinking and / or pressing, which has threaded holes for receiving balancing weights. The balancing ring 78 has no direct mechanical connection to the permanent magnet assembly 74 in order to transmit any axial constraining forces on the permanent magnet assembly 74.

A control and power supply unit 82 is configured to supply the drive motor 66 with electrical energy during operation of the turbomolecular pump 10.

Fig. 2 shows the adjusting ring 84 according to the invention, which can be used in functional terms instead of the conventional adjustment ring 53 described above.

The adjusting ring 84 according to the invention comprises an adjusting portion 86 for axially aligning the stator bearing portion 46 relative to the rotor-side Lagerabschnit 44. From the adjustment portion 86 is a radially encircling collar 88 protrudes, which has a radially outwardly extending radial collar portion 90 and one of this at a Having radially outer edge portion 92 of the radial collar portion 90 resulting angled axial collar portion 94. In the illustrated embodiment, the adjustment portion 86, the radial collar portion 90, and the axial collar portion 94 are integrally formed. It is understood that the adjusting ring 84 in addition to the in Fig. 2 shown radial and axial collar portion 90, 94 may also have at least one further radial and / or axial collar portion.

Viewed in the direction of the longitudinal center axis 47 of the permanent magnet bearing 42, the radial collar portion 90 has a smaller axial dimension than the adjustment portion 86. Moreover, the axial dimensions of the axial collar portion 94 and the adjustment portion 86 are at least approximately equal.

In the illustrated embodiment, the axial dimensions of the adjustment portion 86 and the axial collar portion 94 of the adjustment ring 84 are between 2 and 10 mm, preferably between 3 and 7 mm and more preferably between 4 and 6 mm. The radial collar portion 90 is dimensioned such that its axial dimension is between 0.5 and 2.5 mm, preferably between 0.7 and 2.0 mm and more preferably between 0.8 and 1.5 mm. Furthermore, the adjusting ring 84 has an outer diameter of 45 to 55 mm, preferably 47 to 53 mm and particularly preferably 49 to 50 mm. Such a thing dimensioned adjustment ring 84 is used in a turbomolecular pump 10 with a rotor 18 is used, whose outer diameter is about 160 mm. It is understood that the dimensions of the adjusting ring 84 may deviate from the above-mentioned dimensions of the adjusting ring 84, depending on the size of the turbomolecular pump 10 or the rotor outer diameter.

For magnetic shielding of the rotor 18 from external magnetic fields and for protecting a recipient to be evacuated (not shown) from a magnetic field generated by the permanent magnetic bearing 42, the adjusting ring 84 at least one ferromagnetic, in particular soft magnetic, and / or electrically conductive material.

As based on Fig. 2 it can be seen, the radial collar portion 90 of the collar 88 spans the second bearing portion 44 in the radial direction, whereas the axial collar portion 94 of the collar 88 partially overlaps with the second bearing portion 44 seen in the axial direction. Specifically, the radial collar portion 90 of the collar 88 radially spans the retaining portion 57a and the radially aligned component of the intermediate portion 57b of the locking ring 55 for securing the second bearing portion 44, whereas the axial collar portion 94 of the collar 88 engages the axially angled component of the intermediate portion 57b of the locking ring 55 overlaps, so that the locking ring 55 between the axial collar portion 94 and the adjusting portion 86 of the adjusting ring 84 is arranged in sections. More specifically, the holding portion 57a and the intermediate portion 57b of the lock ring 55 are disposed between the axial collar portion 94 and the adjusting portion 86 of the adjusting ring 84.

By the above-described embodiment of the collar 88 of the adjusting ring 84, a magnetic shield can be achieved where the magnetic field is created by the permanent magnet bearing 42 and where a shield of the Rotor 18 is relevant before external magnetic fields. At the same time, the adjusting ring 84 exposes the pump-active region of the turbomolecular pump 10 formed by the rotor disks 24 and stator disks 26, so that a pumping action of the turbomolecular pump 10 is not impaired or only insignificantly impaired.

By adjusting ring 84 according to the invention can be dispensed with an additional magnetic shielding device, which would span the pump inlet 14 usually in the form of a grid completely or almost completely. Thus, the adjustment ring 84 is better accessible for adjustment purposes via the pump inlet 14, whereby the handling of the turbomolecular pump 10 is much easier.

Likewise is based on Fig. 2 it can be seen that the radial collar portion 90 of the collar 88 and the radial component of the intermediate portion 57b of the locking ring 55 and the axial collar portion 94 of the collar 88 and the axial component of the intermediate portion 57b of the locking ring 55 are at least approximately parallel to each other, wherein the respective sections of the adjusting ring 84 are spaced to the corresponding portions of the locking ring 55, so that ultimately between the adjusting ring 84 and locking ring 55, a labyrinthine annular gap 96 is formed with multi-angled cross-section. In the labyrinthine annular gap 96 foreign bodies can get caught before they reach the bearing gap 52, so that as a result, the bearing gap 52 is particularly effectively protected against contamination by foreign bodies.

According to an advantageous embodiment of the adjusting ring 84, not shown, the circumferential collar 88 has a first radial collar portion 90 projecting from the adjustment portion 86 and an axial collar portion 94 angled therefrom, wherein a second radial collar portion emerges from the first radial collar portion 90, so that yourself the first radial collar portion 90 is radially inward of the second radial collar portion. As a result, the collar 88 of the adjusting ring 84 has a larger diameter, whereby the magnetic shielding effect of the adjusting ring 84 can be increased.

Preferably, an outer edge of the second radial collar portion is aligned at least approximately aligned with an origin 98 of the first rotor disk 24 facing the pump inlet 14 in the axial direction. The origin 98 is that thickened section of the rotor disk 24 which serves to support the rotor disk 24 on the rotor 18 and from which rotor blades 100 of the rotor disk 24 extend in a tapering manner radially outwards.

How especially by Fig. 2 can be seen, located between the origin 98 of the rotor disk 24 and a rotor blade 100 of the rotor disk 24 is a rounded or beveled intermediate portion 102. If the slope of the intermediate portion 102 is continued in the direction of the pump inlet 14 mentally, the slope can also the outer edge of the second radial collar portion of the collar 88 define when the slope and the second radial collar portion are at least approximately at the same axial height. As a result, the outer edge of the second radial collar portion defines the collar 88 of the adjustment ring 84 in a region located radially between the intermediate portion 102 of the rotor disk 24 and the intermediate portion 57b of the lock ring 55.

Moreover, it is also conceivable that the axial collar portion 94 is not aligned parallel to the axis of rotation 20 of the rotor 18, but can also extend obliquely to this, ie the axial collar portion 94 is not orthogonal out of the radial collar portion 90 angled out, but under one of 90th ° deviating angle. Furthermore, it is also conceivable that the collar 88 of the adjusting ring 84 has a plurality of radial and axial collar portions, so that the collar 88 continues in the direction of the first pump inlet 14 facing rotor disk 24 stepped.

In order to further improve the protective effect against contamination, the radial collar portion 90 and / or the axial collar portion 94 of the adjustment ring 84 and / or the locking ring 55 may have structures (not shown), in particular groove-like and preferably spiral groove-like structures, which are facing the labyrinthine annular gap 96 and by means of which a pumping system based on the Holweck and / or Siegbahn pumping principle is formed. Preferably, the pumping action of such a pumping system is such that the gas delivery direction is directed away from the bearing gap 52, so as to counteract an undesirable foreign body counterflow, so that the foreign body can not enter the bearing gap 52 or at least a penetration of the foreign body into the bearing gap 52 difficult is.

LIST OF REFERENCE NUMBERS

10

Turbo molecular pump

12

inlet flange

14

pump inlet

16

casing

17

stator

18

rotor

20

axis of rotation

22

rotor shaft

24

rotor disc

26, 26a, 26b

stator

28

spacer

30

rotor hub

32

Holweckrotorhülse

34

Holweckrotorhülse

36.38

Holweckstatorhülse

40

Rolling

42

Permanent magnetic bearings

43

bearing gap

44

rotor-side bearing section

46

stator-side bearing section

47

Longitudinal central axis

48

magnetic ring

50

magnetic ring

51

spring element

52

bearing gap

53

adjustment

54

safety bearing

55

Restraining

56

spray mother

57a

holding section

57b

intermediate section

57c

attachment section

58

absorbent disc

59

drilling

60

engine compartment

62

Siegbahn stage

64

Sealing gas inlet

66

drive motor

68

motor stator

70

core

72

Kitchen sink

74

Permanent magnet assembly

75a

soft magnetic inference

75b

permanent magnet

76

motor gap

78

balancing ring

80

encapsulation

82

Control and power supply unit

84

adjustment

86

adjusting

88

collar

90

radial collar section

92

border area

94

axial collar section

96

annular gap

98

origin

100

rotor blades

102

intermediate area

Claims (14)

Adjusting ring (84) having an adjusting section (86) for axially aligning a radially inner first bearing section (46) of a bearing (42) of a vacuum pump (10), in particular turbomolecular pump (10), in the direction of a longitudinal central axis (47) of the bearing (42 ) relative to a radially outer second bearing portion (44) of the bearing (42) of the vacuum pump (10),
characterized in that
a circumferential collar (88) protruding from the adjustment portion (86) of the adjustment ring (84) having a radially outwardly extending radial collar portion (90). Adjusting ring (84) according to claim 1,
characterized in that
an axial collar portion (94) emerges angled out of the radial collar portion (90). Adjusting ring (84) according to claim 2,
characterized in that
the axial collar portion (94) on a radially outer edge region (92) of the radial collar portion (90) thereof emerges. Adjusting ring (84) according to at least one of claims 1 to 3,
marked by
at least one further radial collar portion, in particular which emerges from the radial collar portion (90) or the axial collar portion (94), and / or
at least one further axial collar portion, in particular which emerges from the radial collar portion (90) or the axial collar portion (94). Adjustment ring (84) according to at least one of claims 1 to 4,
characterized in that
the or each radial collar portion (90) has a smaller axial dimension than the adjustment portion (86) and / or
the or each axial collar portion (94) and the adjustment portion (86) have at least approximately equal axial dimensions. Adjusting ring (84) according to at least one of claims 1 to 5,
characterized in that
the adjusting ring (84) has, at least in sections, a ferromagnetic, in particular soft magnetic, and / or electrically conductive material. Bearing (42) for a vacuum pump (10), in particular turbomolecular pump (10), with a radially inner first bearing section (46), a radially outer second bearing section (44) and an adjusting ring (84) according to at least one of claims 1 to 6 for axial alignment of the first bearing portion (46) relative to the second bearing portion (44) in the direction of a longitudinal center axis (47) of the bearing (42),
characterized in that
the radially extending collar portion (90) spans the second bearing portion (44) in the radial direction. Bearing (42) according to claim 7 having an adjusting ring according to at least one of claims 2 to 6,
characterized in that
the axial collar portion (94) partially overlaps axially with the second bearing portion (44). Bearing (42) according to claim 8,
marked by
a locking ring (55) for locking the second bearing portion (44), which viewed in the radial direction at least in sections between the adjusting portion (56) and the axial collar portion (94) is arranged. Bearing (42) according to claim 9,
characterized in that
the locking ring (55) together with the adjusting ring (84) defines an annular gap (96) with a multi-angled cross-section. Bearing (42) according to at least one of claims 7 to 10,
characterized in that
the bearing (42) is a magnetic bearing (42) and the first and second bearing portions (46, 44) each comprise at least one magnet (48, 50). Vacuum pump (10), in particular turbomolecular pump (10), having a rotor (18) rotatably mounted relative to a stator (17) and a bearing (42) according to at least one of claims 7 to 11 for supporting the rotor (18) on the stator (17). Vacuum pump (10) according to claim 12,
characterized in that
the stator (17) is arranged radially inside the rotor (18). Vacuum pump (10) according to claim 12 or 13,
characterized in that
the adjusting ring (84) is in threaded engagement with the stator (17).

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