Turbomolecular vacuum pump

Abstract

A turbomolecular vacuum pump comprises a stator, at least one rotor with a plurality of circumferentially distributed rotor blades which can be driven to rotate about an axis of rotation in order to generate a pumping action, and at least one stator disk attached to the stator which cooperates with the rotor to generate the pumping action and comprises a plurality of circumferentially distributed stator blades which define a blade plane, wherein the stator disk for attachment to the stator comprises a mounting section with an end section by which the stator disk is attached to the stator and which defines a mounting plane, and wherein the blade plane and the mounting plane are perpendicular to the axis of rotation and spaced apart from each other along the axis of rotation.

Description

[0001] The invention relates to a turbomolecular vacuum pump.

[0002] Publication EP 0 967 395 A2 discloses a vacuum pump according to the preamble of claim 1. Publications EP 3 734 078 A2 and EP 1918588 A2 disclose related vacuum pumps. These known vacuum pumps each comprise at least one stator disk attached to a stator, which interacts with a rotor to generate the pumping action and comprises a plurality of circumferentially distributed stator blades that define a blade plane.

[0003] The blade plane is a plane perpendicular to the axis of rotation in which the stator blades lie. This means the blade plane can be defined by any section of the stator blades, as long as it intersects or touches them. For example, the blade plane can run centrally through the stator blades in the axial direction parallel to the axis of rotation, or it can be defined by the upper or lower blade edges.

[0004] Turbomolecular vacuum pumps are designed, among other things, to have the highest possible pumping speed. In this context, the design of the suction area is of particular importance; that is, the area near the pump inlet that defines the inlet plane. Here, optimal utilization of the installation space available in the pump housing for accommodating pump-active components, especially the rotor-stator assembly closest to the pump inlet, is crucial. In this context, a rotor-stator assembly is understood to be a package of rotor disks and stator disks arranged alternately one above the other in the axial direction.

[0005] Stator disks are typically attached to the stator by clamping their radially outer regions. This clamping or clamping is achieved using spacer rings inserted into the pump housing in a plane axially aligned with the plane of the blades. The spacer rings and the pump housing are components of the vacuum pump's stator; that is, within the scope of this disclosure, the pump housing is considered a component of the stator. A stator disk is clamped between two axially consecutive spacer rings. For example, in the case of laminated stator disks, a radially outer circumferential flange of the stator disk is axially clamped by spacer rings. In contrast, in the case of milled or sawn stator disks, the blades can be axially clamped with their radially outer blade tips, i.e., their free end sections. The axial clamping of the stator disks to the stator requires radial installation space within the pump housing.

[0006] When designing the intake area of ​​a turbomolecular vacuum pump, i.e., the area of ​​the pumping components closest to the pump inlet, the aim is to achieve the highest possible pumping speed by positioning the rotor-stator assembly axially as close as possible to the pump inlet. This means that the first stator disk on the intake side should be located axially as close as possible to the pump inlet to minimize flow losses. At the same time, the rotor-stator assembly, and therefore also the first stator disk, should have the largest possible outer diameter relative to the inner diameter of the respective pump housing.

[0007] It should be noted that the installation space in the pump inlet area is limited by the pump flange and the connecting elements used to link the pump flange to the flange of a receiver. These elements can include screws, and sufficient space must be available in the flange area for handling the screws and for the necessary tool to tighten them. Furthermore, the pump flange must meet specific requirements, particularly regarding its diameter, such as those specified in ISO standards.

[0008] The aforementioned boundary conditions limit the installation space available for the rotor and stator disks in the area of ​​the pump inlet, so that the rotor-stator package cannot be positioned arbitrarily close to the pump inlet if, at the same time, the outer diameter of the first stator disk is to be as large as possible.

[0009] It is therefore an object of the invention to provide a turbomolecular vacuum pump which has an improved pumping speed with regard to the respective conditions in the area of ​​the pump inlet.

[0010] This problem is solved according to the invention by a turbomolecular vacuum pump according to claim 1.

[0011] The end section is the section of the mounting section which interacts directly with the stator (e.g. with a spacer ring and a shoulder section of the pump housing or with two spacer rings) to attach the stator disk to the stator.

[0012] The mounting plane is a plane in which at least one section of the end section lies which is axially further away from the blade plane than other areas of the mounting section.

[0013] Because the mounting plane and the blade plane are axially spaced apart, the blade plane can be positioned closer to the pump inlet while maintaining the same axial position of the mounting on the stator. This reduces flow losses in the inlet area and improves pumping speed. Calculations based on parameters of existing turbomolecular vacuum pumps have shown that pumping speed improvements of more than 3% can be achieved for a gas that is relevant in practice, namely nitrogen. In one example, the calculation assumed that the rotor-stator assembly closest to the pump inlet was positioned 10 mm closer to the pump inlet than it would be without the inventive design. This resulted in an increase in pumping speed for nitrogen from 240 liters / second with the conventional design to 249 liters / second with the inventive design.

[0014] The geometry of the inlet area, in particular the pump housing and the flange area, does not need to be modified for the invention. A pump according to the invention therefore continues to meet the respective requirements such as ISO standards.

[0015] Advantageous embodiments of the invention are specified in the dependent claims, the description and the drawing.

[0016] The blade plane is axially closer to a pump inlet than the mounting plane. This allows existing structural features of turbomolecular vacuum pumps, in particular a shoulder section of the pump housing located in or near the inlet area, to continue to be used for mounting a stator disk, especially the first stator disk.

[0017] According to one embodiment, the stator disk is formed in one piece.

[0018] The stator disk can be a stamped and / or bent sheet metal part, i.e., a so-called laminated stator disk, or it can be manufactured by machining a starting part. These methods for manufacturing stator disks are generally known and compatible with the invention insofar as they also permit the production of stator disks designed according to the invention with axially spaced blade and mounting planes.

[0019] Laminated stator disks typically consist of two semicircular or semicircular annular halves to facilitate or even enable assembly. When "the stator disk" is mentioned in this context, it refers to both halves together. Therefore, when the present disclosure refers to a one-piece or single-part design in connection with such laminated stator disks, it means that the two halves of the stator disk are each formed in one piece.

[0020] In a laminated stator disk, the mounting section can be formed by a radially outer flange of the stator disk, which has an end section radially outside and is connected to the stator blades radially inside. While known laminated stator disks are disk-shaped over their entire diameter, i.e., including the radially outer flange, a laminated stator disk according to the invention is thus provided radially outside with a mounting section that leads from the blade plane to the mounting plane defined by its end section.

[0021] In principle, it is also possible, depending on the specific design of the turbomolecular vacuum pump, for a radially inner flange of the stator disk to be designed as a fastening section, so that the stator disk can be clamped radially inside to the stator.

[0022] The fastening section can have a radially outer or radially inner flange section that lies in the plane of the blades and is connected to the stator blades.

[0023] According to another embodiment, the mounting section is formed by free end sections of the stator blades. In particular, sawn or milled stator disks can be designed in this way. At least some, preferably all, stator blades then have a radial, in particular radially outer, end section that leads from the blade plane to the mounting plane, these end sections together forming the mounting section of the stator disk.

[0024] According to one embodiment, the mounting section comprises a transition section that extends from the blade plane to the end section of the mounting section. The dimensions and / or shape of the transition section can, in principle, be chosen arbitrarily, particularly to adjust the axial distance between the blade plane and the mounting plane. The transition section is not directly attached to the stator; rather, the stator disk is attached to the stator, for example, by clamping, via the end section.

[0025] According to one embodiment, the transition section has at least a cylindrical or conical shape in some sections, with the axis of rotation as the central axis.

[0026] According to one embodiment, the end section of the mounting section has an annular or conical shape with the axis of rotation as its central axis, or exhibits a curved profile in a cross-sectional plane containing the axis of rotation. The shape of the end section can, in principle, be chosen arbitrarily and, in particular, depending on the desired method of clamping to the stator.

[0027] According to one embodiment, the mounting section comprises or has an L-shape in a cross-sectional plane containing the axis of rotation. Figuratively speaking, the stator disk can be pot-shaped or hat-shaped.

[0028] According to one embodiment, the L-shape is formed by a transition section and the end section of the mounting section. Here, the transition section runs parallel to the axis of rotation, while the end section extends perpendicular to the axis of rotation and thus in the mounting plane; that is, the end section defining the mounting plane lies completely within the mounting plane.

[0029] According to one embodiment, the stator disk is part of a turbomolecular pumping stage comprising a plurality of stator disks and a plurality of rotor disks, each containing several rotor blades, wherein the stator disks and the rotor disks interact to generate the pumping action. The turbomolecular pumping stage can comprise one or more rotor-stator assemblies. The stator disk is part of the first rotor-stator assembly, i.e., the one closest to the pump inlet. Thus, the first stator disk of the rotor-stator assembly, i.e., the one closest to the pump inlet, is designed according to the invention.

[0030] According to one embodiment, the stator disk is the one axially closest to the pump inlet among a plurality of axially spaced stator disks of the stator. Additionally or alternatively, one or more structurally identical stator disks can be provided, in which the blade plane is axially closer to a pump inlet than the mounting plane. The axial distance between the blade plane and the mounting plane can be either the same or vary for all stator disks designed according to the invention, e.g., increasing or decreasing in the direction of the pump inlet. Structurally identical stator disks are those in which the blade plane and the mounting plane are axially spaced from each other, i.e., along the axis of rotation.In this sense, stator disks of identical construction can be identical, although this is not necessarily the case, and the stator disks can differ from each other in other respects. For example, stator disks of identical construction can have different diameters. The axial distance between the blade plane and the mounting plane can also differ between stator disks of identical construction.

[0031] According to one embodiment, the stator disk is axially clamped to the stator by the end section of the mounting section. This method of attaching stator disks to the stator is generally known and therefore compatible with the invention; that is, the invention does not necessarily require new fastening methods.

[0032] According to the invention, the stator, in particular a pump housing forming part of the stator, comprises, in the region of a pump inlet, a flange section for establishing a mechanical connection with a receiver, and a shoulder section axially spaced from the pump inlet. Together with the flange section, the shoulder section defines a mounting area for at least one connecting element, in particular at least one screw, to be attached to the flange section. Exactly one stator disk is clamped between a spacer ring designed as a separate component and the shoulder section, or two or more stator disks are clamped between the spacer ring and the shoulder section. Here, too, only one, several, or all of the two or more stator disks can be designed according to the invention, i.e., they can have a distance between the blade plane and the mounting plane.

[0033] Such a configuration of the inlet area of ​​turbomolecular vacuum pumps, i.e., a configuration with a shoulder section axially spaced from the flange section, is generally known; that is, the invention is also compatible with such configurations. The stator disk of the turbomolecular vacuum pump according to the invention is thus designed such that it can be clamped to a shoulder section of the stator, in particular the pump housing. According to the invention, the stator disk clamped between the spacer ring and the shoulder section is the stator disk axially closest to the pump inlet, whose mounting plane is located in the region of the shoulder section and whose blade plane lies between the pump inlet and the shoulder section. The invention is described below by way of example with reference to the drawing. The drawing shows: Fig. 1 a perspective view of a turbomolecular pump according to the prior art, Fig. 2 a view of the underside of the turbomolecular pump of Fig. 1 , Fig. 3 a cross-section of the turbomolecular pump along the in Fig. 2 Section line AA shown, Fig. 4 a cross-sectional view of the turbomolecular pump along the in Fig. 2 Section line BB, Fig. 5 shows a cross-sectional view of the turbomolecular pump along the line shown in Fig. 2 Section line CC shown, Fig. 6A, 6B stator disks of the prior art each in a simplified side view, Fig. 7 a simplified side view of a stator disk according to the invention, Fig. 8 a simplified top view of one half of a stator disk consisting of two halves according to the invention, Figs. 9A-9C each a simplified cross-sectional view of a part of a turbomolecular vacuum pump according to the invention, and Figs. 10A-10E views accordingly Fig. 9A to illustrate alternative, non-inventive possibilities for attaching the stator disk to the stator.

[0034] The in Fig. 1 The turbomolecular pump 111 shown, according to the prior art, comprises a pump inlet 115 surrounded by an inlet flange 113, to which a receiver (not shown) can be connected in a manner known per se. The gas from the receiver can be drawn out of the receiver via the pump inlet 115 and conveyed through the pump to a pump outlet 117, to which a backing pump, such as a rotary vane pump, can be connected.

[0035] The inlet flange 113 forms a Fig. 1 The upper end of the housing 119 of the vacuum pump 111. The housing 119 comprises a lower part 121, to which an electronics housing 123 is attached laterally. The electronics housing 123 contains electrical and / or electronic components of the vacuum pump 111, e.g., for operating an electric motor 125 located in the vacuum pump (see also Fig. 3 The electronics housing 123 has several connections 127 for accessories. In addition, a data interface 129, e.g. according to the RS485 standard, and a power supply connection 131 are located on the electronics housing 123.

[0036] There are also turbomolecular pumps that do not have such an attached electronics housing, but are connected to external drive electronics.

[0037] The housing 119 of the turbomolecular pump 111 has a flood inlet 133, in particular in the form of a flood valve, through which the vacuum pump 111 can be flooded. In the area of ​​the lower part 121, a purge gas connection 135, also referred to as a purge gas connection, is also arranged, through which purge gas can be supplied to protect the electric motor 125 (see e.g. Fig. 3 The gas pumped by the pump can be introduced into the motor compartment 137, in which the electric motor 125 is housed in the vacuum pump 111. Two coolant connections 139 are also arranged in the lower part 121, one of which serves as an inlet and the other as an outlet for coolant that can be directed into the vacuum pump for cooling purposes. Other existing turbomolecular vacuum pumps (not shown) are operated exclusively with air cooling.

[0038] The lower side 141 of the vacuum pump can serve as a base, allowing the vacuum pump 111 to be operated standing upright on its underside 141. Alternatively, the vacuum pump 111 can be attached to a receiver via the inlet flange 113 and thus operated in a suspended position. Furthermore, the vacuum pump 111 can be designed to operate even when oriented differently than described. Fig. 1 As shown. It is also possible to implement embodiments of the vacuum pump in which the underside 141 can be arranged facing sideways or upwards instead of downwards. In principle, any angle is possible.

[0039] Other existing turbomolecular vacuum pumps (not shown), which are particularly larger than the pump shown here, cannot be operated in a standing position.

[0040] On the underside 141, which is in Fig. 2 As shown, various screws 143 are arranged, by means of which components of the vacuum pump, not further specified here, are fastened to one another. For example, a bearing cover 145 is attached to the underside 141.

[0041] Mounting holes 147 are also arranged on the underside 141, via which the pump 111 can be attached to a support surface, for example. This is not possible with other existing turbomolecular vacuum pumps (not shown), which are particularly larger than the pump shown here.

[0042] In the Figuren 2 bis 5 A coolant line 148 is shown in which the coolant introduced and removed via the coolant connections 139 can circulate.

[0043] Like the sectional views of the Figuren 3 bis 5 As shown, the vacuum pump comprises several process gas pumping stages for conveying the process gas present at the pump inlet 115 to the pump outlet 117.

[0044] A rotor 149 is arranged in the housing 119, which has a rotor shaft 153 rotatable about a rotation axis 151.

[0045] The turbomolecular pump 111 comprises several turbomolecular pump stages connected in series to provide pumping action. These stages have several radial rotor disks 155 attached to the rotor shaft 153 and stator disks 157 arranged between the rotor disks 155 and fixed in the housing 119. Each rotor disk 155 and an adjacent stator disk 157 form a turbomolecular pump stage. The stator disks 157 are held at a desired axial distance from each other by spacer rings 159.

[0046] The vacuum pump also includes Holweck pump stages arranged radially within one another and connected in series to effectively pump the pump. Other turbomolecular vacuum pumps exist (not shown) that do not have Holweck pump stages.

[0047] The rotor of the Holweck pump stages comprises a rotor hub 161 arranged on the rotor shaft 153 and two cylindrical Holweck rotor sleeves 163, 165 attached to and supported by the rotor hub 161, which are oriented coaxially to the axis of rotation 151 and nested one inside the other in the radial direction. Furthermore, two cylindrical Holweck stator sleeves 167, 169 are provided, which are also oriented coaxially to the axis of rotation 151 and nested one inside the other in the radial direction.

[0048] The pump-active surfaces of the Holweck pump stages are formed by the outer surfaces, i.e., the radial inner and / or outer surfaces, of the Holweck rotor sleeves 163, 165 and the Holweck stator sleeves 167, 169. The radial inner surface of the outer Holweck stator sleeve 167 faces the radial outer surface of the outer Holweck rotor sleeve 163, forming a radial Holweck gap 171, and together they form the first Holweck pump stage following the turbomolecular pumps. The radial inner surface of the outer Holweck rotor sleeve 163 faces the radial outer surface of the inner Holweck stator sleeve 169, forming a radial Holweck gap 173, and together they form a second Holweck pump stage. The radial inner surface of the inner Holweck stator sleeve 169 lies opposite the radial outer surface of the inner Holweck rotor sleeve 165, forming a radial Holweck gap 175, and together they form the third Holweck pumping stage.

[0049] At the lower end of the Holweck rotor sleeve 163, a radially extending channel can be provided, through which the radially outer Holweck slot 171 is connected to the central Holweck slot 173. Furthermore, a radially extending channel can be provided at the upper end of the inner Holweck stator sleeve 169, through which the central Holweck slot 173 is connected to the radially inner Holweck slot 175. This connects the nested Holweck pump stages in series. A connecting channel 179 to the outlet 117 can also be provided at the lower end of the radially inner Holweck rotor sleeve 165.

[0050] The aforementioned pump-active surfaces of the Holweck stator sleeves 167, 169 each have several Holweck grooves spiraling around the axis of rotation 151 in the axial direction, while the opposite outer surfaces of the Holweck rotor sleeves 163, 165 are smooth and drive the gas forward in the Holweck grooves for the operation of the vacuum pump 111.

[0051] For the rotatable mounting of the rotor shaft 153, a rolling bearing 181 is provided in the area of ​​the pump outlet 117 and a permanent magnet bearing 183 is provided in the area of ​​the pump inlet 115.

[0052] In the area of ​​the rolling bearing 181, a conical injection nut 185 with an outer diameter increasing towards the rolling bearing 181 is provided on the rotor shaft 153. The injection nut 185 is in sliding contact with at least one wiper of a fluid reservoir. In other existing turbomolecular vacuum pumps (not shown), an injection screw may be provided instead of an injection nut. Since different designs are thus possible, the term "injection tip" is also used in this context.

[0053] The operating fluid reservoir comprises several stacked absorbent discs 187, which are impregnated with an operating fluid for the rolling bearing 181, e.g. with a lubricant.

[0054] During operation of the vacuum pump 111, the operating fluid is transferred by capillary action from the fluid reservoir via the wiper to the rotating injection nut 185 and, as a result of centrifugal force, is conveyed along the injection nut 185 in the direction of the increasing outer diameter of the injection nut 185 towards the rolling bearing 181, where it performs, for example, a lubricating function. The rolling bearing 181 and the fluid reservoir are enclosed in the vacuum pump by a trough-shaped insert 189 and the bearing cover 145.

[0055] The permanent magnet bearing 183 comprises a rotor-side bearing half 191 and a stator-side bearing half 193, each containing a ring stack of several axially stacked permanent magnet rings 195, 197. The ring magnets 195, 197 face each other, forming a radial bearing gap 199, with the rotor-side ring magnets 195 arranged radially outside and the stator-side ring magnets 197 radially inside. The magnetic field present in the bearing gap 199 induces magnetic repulsion forces between the ring magnets 195, 197, which result in the radial support of the rotor shaft 153. The rotor-side ring magnets 195 are supported by a support section 201 of the rotor shaft 153, which radially surrounds the ring magnets 195 on the outside.The stator-side ring magnets 197 are supported by a stator-side support section 203, which extends through the ring magnets 197 and is suspended from radial struts 205 of the housing 119. Parallel to the axis of rotation 151, the rotor-side ring magnets 195 are fixed by a cover element 207 coupled to the support section 201. The stator-side ring magnets 197 are fixed in one direction, parallel to the axis of rotation 151, by a retaining ring 209 connected to the support section 203 and a retaining ring 211 also connected to the support section 203. A disc spring 213 may also be provided between the retaining ring 211 and the ring magnets 197.

[0056] Within the magnetic bearing, an emergency or catch bearing 215 is provided, which runs freely without contact during normal operation of the vacuum pump 111 and only engages when there is excessive radial deflection of the rotor 149 relative to the stator, in order to form a radial stop for the rotor 149 and thus prevent a collision between the rotor-side and stator-side structures. The catch bearing 215 is designed as an unlubricated rolling bearing and forms a radial gap with the rotor 149 and / or the stator, which causes the catch bearing 215 to be disengaged during normal pump operation. The radial deflection at which the catch bearing 215 engages is dimensioned to be large enough so that the catch bearing 215 does not engage during normal operation of the vacuum pump, and simultaneously small enough to prevent a collision between the rotor-side and stator-side structures under all circumstances.

[0057] The vacuum pump 111 comprises the electric motor 125 for rotating the rotor 149. The armature of the electric motor 125 is formed by the rotor 149, whose rotor shaft 153 extends through the motor stator 217. A permanent magnet arrangement can be arranged radially on the outside or embedded in the section of the rotor shaft 153 extending through the motor stator 217. A space 219 is arranged between the motor stator 217 and the section of the rotor 149 extending through the motor stator 217. This space comprises a radial motor gap through which the motor stator 217 and the permanent magnet arrangement can magnetically influence each other to transmit the drive torque.

[0058] The motor stator 217 is fixed in the housing within the motor compartment 137 provided for the electric motor 125. A purge gas, also known as a sealing gas, which can be, for example, air or nitrogen, can enter the motor compartment 137 via the purge gas connection 135. This purge gas protects the electric motor 125 from process gas, e.g., from corrosive components of the process gas. The motor compartment 137 can also be evacuated via the pump outlet 117, meaning that the vacuum pressure in the motor compartment 137 is at least approximately equal to that produced by the backing pump connected to the pump outlet 117.

[0059] Between the rotor hub 161 and a wall 221 bounding the engine compartment 137, a so-called labyrinth seal 223, which is known per se, can also be provided, in particular to achieve a better seal of the engine compartment 217 against the radially outside Holweck pump stages.

[0060] A turbomolecular vacuum pump according to the invention, as explained below with reference to Figs. 7ff, can be designed with respect to the features not shown in Figs. 7ff as described above with reference to the Fig. 1 bis 5 has been described.

[0061] The Fig. 6A und 6B Figure 20 illustrates, in a highly simplified side view, laminated stator disks according to the state of the art, as used in a conventional intake area of ​​a turbomolecular vacuum pump.

[0062] The stator disks 20, produced by punching and bending and thus formed in one piece, each comprise a radially outer flange 24 – hereinafter also referred to as outer flange – and a (not shown) radially inner flange – hereinafter also referred to as inner flange – as well as several stator blades 22 located between them, which are inclined relative to a blade plane 26 defined by the flanges by bending. Fig. 6A The stator blades 22 protrude on both sides of the blade plane 26, according to Fig. 6B only on one side. The outer flange 24 serves to attach the stator disk 20 to a stator (not shown) by clamping the outer flange 24, for example, between two spacer rings. The outer flange 24 thus also defines a mounting plane 32, i.e., in the known stator disks 20, the blade plane 26 and the mounting plane 32 coincide.

[0063] The in Fig. 7 (see also) Fig. 8 and 9A The laminated stator disk 20 shown in the invention comprises, according to a known laminated stator disk (such as in, for example, in Fig. 6B (shown) between an inner flange (not shown) and a radially outer flange section 24a – hereinafter referred to as outer flange 24a – stator blades 22 angled to one side. The outer flange 24a, lying in the blade plane 26, is part of a specially designed mounting section 28, which, in addition to the outer flange 24a, comprises an end section 30, which defines a mounting plane 32 extending at an axial distance 52 from the blade plane 26, and an axially extending (i.e., parallel to the axial direction Z) transition section 34 leading from the outer flange 24a – i.e., from the blade plane 26 – to the mounting plane 32. This laminated stator disk 20 according to the invention can also be manufactured by punching and bending, similar to a known laminated stator disk. The distance 52 between the blade plane 26 and the mounting plane 32 is, for example, 10 mm.

[0064] The end section 30 serves to attach the stator disk 20 to a stator of a turbomolecular vacuum pump. This is followed by... Fig. 9A discussed in more detail.

[0065] Fig. 8 It can be seen that the halves of a two-part laminated stator disk 20 according to the invention, of which in Fig. 8 only one half is shown, and each half is correspondingly Fig. 7 and Fig. 9A The two inner flanges 24a and the radially inner flange section 24b (hereinafter referred to as the inner flange 24b) are each annular in shape, i.e., both the outer flange 24a and the radially inner flange section 24b are semicircular. The inclined stator blades 22 are located between the inner flange 24b and the outer flange 24a. In the assembled state, the two inner flanges 24b of the two halves of the stator disk 20 define a circular opening through which the rotor (not shown) of the turbomolecular pump extends, its axis of rotation then coinciding with the central axis of the stator disk 20 formed by the two halves. This can be seen in... Fig. 8 in addition, the transition section 34 extending in the axial direction Z and the end section 30 extending perpendicular to it and projecting radially outwards from the transition section 34.

[0066] As in the Fig. 9A As shown, the end section 30 of the mounting section 28 of the stator disk 20 closest to the pump inlet 36 is clamped between a spacer ring 50 and a shoulder section 40 of the pump housing 38. The blade plane 26 is therefore closer to the inlet plane 54 defined by the flange section 42 and the pump inlet 36 than the mounting plane 32. This allows the distance 56 between the inlet plane 54 and the blade plane 26 to be reduced compared to known pumps, which has a positive effect on the performance of the turbomolecular vacuum pump 10, as flow losses are reduced.

[0067] Between the shoulder section 40 and the flange section 42 there is a mounting area 44, through which the heads 48 of circumferentially distributed fastening screws 46 are accessible, with which the flange section 42 can be screwed to a receiver not shown.

[0068] The blade plane 26 is located at the level of the mounting area 44, which until now has remained unused for the arrangement of stator disks due to the reduced inner diameter of the pump housing 12.

[0069] The one in Fig. 9A The stator disk 20 shown is the first, i.e., the one closest to the pump inlet 36, and forms part of a turbomolecular pump stage comprising a plurality of stator disks 20 and a plurality of rotor disks 58 of the rotor 14, each equipped with rotor blades 16. Only the first rotor disk 58 is in Fig. 9A The further stator disks, not shown, are each clamped between two spacer rings 50 and can be designed as a continuous disk shape as in the prior art or also in a manner according to the invention with a mounting plane axially spaced from the blade plane.

[0070] The transition section 34 has a cylindrical shape, wherein the outer collar 24a and the transition section 34 as well as the transition section 34 and the end section 30 each enclose an angle of at least substantially 90°, so that the fastening section 28 has an L-shape in a section plane containing the axis of rotation 18 and the stator disk 20 as a whole has a hat or pot shape.

[0071] The Fig. 9B and 9CThe figures show that two or more stator disks 20 can also be clamped between a spacer ring 50 and the shoulder section 40. Between the stator disk 20 closest to the pump inlet 36 and the next or subsequent stator disk 20, a further rotor disk 58 with rotor blades 16 is provided. The further stator disk 20, clamped between the spacer ring 50 and the shoulder section 40, can be designed according to the invention with a mounting plane 32 axially spaced from the blade plane 26 (see Figure 1). Fig. 9B The further stator disk 20 can also be designed as a continuous disk shape, as in the prior art (see Fig. 9C ).

[0072] Fig. 10A In an embodiment that does not correspond to the invention, the stator disk 20 can also be clamped between two spacer rings 50 of the stator 12 with the end section 30 of its mounting section 28.

[0073] The exemplary embodiments, which are also not in accordance with the invention, Fig. 10B bis 10E differ from that of the Fig. 9A by the shape of the fastening section 28 including the end section 30 and by the shape of the clamping surfaces of the spacer rings 50. These exemplary embodiments illustrate that the design of a stator disk 20 according to the invention is not limited to the hat or pot shape according to Fig. 9A is limited, but the fastening section 28 can basically have any shape.

[0074] The spacer rings 50 can each be adapted to the shape of the end section 30 with their clamping surfaces, as shown in the Fig. 10B bis 10E can also be removed. The clamping surfaces of the spacer rings 50 do not need to be exactly adapted to the shape of the respective end section 30. In a specific case, it may be acceptable or even desirable for the end section 30 of the stator disk 20 to deform when clamped and thus adapt itself to the interacting clamping surfaces of the spacer rings 50. According to Fig. 10B The transition section 34 is conical and transitions into the end section 30, which is also conical and has the same cone angle, and whose free end defines the fastening plane 32.

[0075] In the exemplary embodiment of Fig. 10C is unlike that of the Fig. 10B No outer flange lying in the blade plane 26 is provided, i.e. the transition section 34 leads directly from the radially outer ends of the blades 22 to the end section 30.

[0076] According to Fig. 10D Both the transition section 34 and the end section 30 are curved. The curvature can, in principle, be chosen arbitrarily. The fastening plane 32 is defined here by the apex of the end section 30.

[0077] The exemplary embodiment of the Fig. 10E corresponds to that of the Fig. 10B , however, there is no transition section, but the end section 30 clamped between the spacer rings 50 connects directly to the outer collar 24a. Bezugszeichenliste

[0078] 10 Turbomolecular vacuum pump 12 Stator 14 Rotor 16 Rotor blades 18 Rotation axis 20 Stator disk 22 Stator blades 24 Collar 24a, 24b Collar section 26 Blade plane 28 Mounting section 30 End section 32 Mounting plane 34 Transition section 36 Pump inlet 38 Pump housing 40 Shoulder section 42 Flange section 44 Mounting area 46 Screw 48 Screw head 50 Spacer ring 52 Distance between blade plane and mounting plane 54 Inlet plane at pump inlet 56 Distance between inlet plane and blade plane 58 Rotor disk 111 Turbomolecular pump 113 Inlet flange 115 Pump inlet 117 Pump outlet 119 Housing 121 Lower part 123 Electronics housing 125 Electric motor 127 Accessory connection 129 Data interface 131 Power supply connection 133 Flood inlet 135 Sealing gas connection 137 Motor compartment 139 Coolant connection 141 Underside 143 Screw 145 Bearing cover 147 Mounting hole 148 Coolant line 149 Rotor 151 Rotation shaft 153 Rotor shaft 155 Rotor disc 157 Stator disc 159 Spacer ring 161 Rotor hub163 Holweck rotor sleeve 165 Holweck rotor sleeve 167 Holweck stator sleeve 169 Holweck stator sleeve 171 Holweck gap 173 Holweck gap 175 Holweck gap 179 Connecting channel 181 Rolling bearing 183 Permanent magnet bearing 185 Injection nut 187 Washer 189 Insert 191 Rotor-side bearing half 193 Stator-side bearing half 195 Ring magnet 197 Ring magnet 199 Bearing gap 201 Support section 203 Support section 205 Radial strut 207 Cover element 209 Support ring 211 Mounting ring 213 Disc spring 215 Emergency or catch bearing 217 Motor stator 219 Gap 221 Wall 223 Labyrinth seal

Claims

1. A turbomolecular vacuum pump (10) comprising: a stator (12); at least one rotor (14) which has a plurality of rotor blades (16) arranged distributed in the peripheral direction and which can be driven to perform a rotation about an axis of rotation (21, 18) in order to generate a pumping effect; and at least one stator disk (20) which is fastened to the stator (12), which cooperates with the rotor (14) to generate the pumping effect and which comprises a plurality of stator blades (22) which are arranged distributed in the peripheral direction and which define a blade plane (26), wherein the stator disk (20) comprises a fastening section (28) for fastening to the stator (12), said fastening section (28) having an end section (30) with which the stator disk (20) is fastened to the stator (12) and which defines a fastening plane (32), and wherein the blade plane (26) and the fastening plane (32) extend perpendicular to the axis of rotation (18) and are spaced apart along the axis of rotation (18), wherein the stator (12) comprises a flange section (42) in the region of a pump inlet (36) for establishing a mechanical connection with a recipient, wherein the stator (12) further comprises a shoulder section (40) which is axially spaced apart from the pump inlet (36) and which, together with the flange section (42), defines an assembly region (44) for at least one connection element to be attached to the flange section (42), characterized in that exactly one stator disk (20) is clamped between a spacer ring (50) configured as a separate component and the shoulder section (40), or wherein two or more stator disks (20) are clamped between a spacer ring (50) configured as a separate component and the shoulder section (40), wherein the exactly one stator disk (20) or one of the two or more stator disks (20) is the stator disk (20) which is disposed axially closest to the pump inlet (36), whose fastening plane (32) is disposed in the region of the shoulder section (40) and whose blade plane (26) is disposed between the pump inlet (36) and the shoulder section (40).

2. A vacuum pump (10) according to claim 1, wherein the exactly one stator disk (20) or the one of the two or more stator disks (20) is formed in one piece, and / or wherein the exactly one stator disk (20) or the one of the two or more stator disks (20) is a stamped and / or bent part composed of sheet metal or is produced by a chip-forming machining of an initial part, in particular by sawing and / or milling the initial part.

3. A vacuum pump (10) according to at least one of the preceding claims, wherein the fastening section (28) is formed by a collar (24) of the exactly one stator disk (20) or of the one of the two or more stator disks (20), which collar (24) radially outwardly has the end section (30) and is radially inwardly connected to the stator blades (22), or vice versa, and / or wherein the fastening section (28) comprises a radially outer or radially inner collar section (24a, 24b) which lies in the blade plane (26) and is connected to the stator blades (22).

4. A vacuum pump (10) according to at least one of the claims 1 or 2, wherein the fastening section (28) is formed by free end sections of the stator blades (22).

5. A vacuum pump (10) according to at least one of the preceding claims, wherein the fastening section (28) comprises a transition section (34) which leads from the blade plane (26) to the end section (30) of the fastening section (28), in particular wherein the transition section (34) at least sectionally has a cylindrical or conical shape with the axis of rotation (18) as the central axis.

6. A vacuum pump (10) according to at least one of the preceding claims, wherein the end section (30) of the fastening section (28) has a circular ring shape or a conical shape with the axis of rotation (18) as the central axis or has a curved course in a sectional plane containing the axis of rotation (18).

7. A vacuum pump (10) according to at least one of the preceding claims, wherein the fastening section (28) has or comprises an L shape in a sectional plane containing the axis of rotation (18), in particular wherein the L shape is formed by a transition section (34), which leads from the blade plane (26) to the end section (30) of the fastening section (28), and the end section (30) of the fastening section (28).

8. A vacuum pump (10) according to at least one of the preceding claims, wherein the exactly one stator disk (20) or the one of the two or more stator disks (20) is a part of a turbomolecular pump stage which comprises a plurality of stator disks (20) and a plurality of rotor disks (58) of the rotor (14) that each comprise a plurality of rotor blades (16), wherein the stator disks (20) and the rotor disks (58) cooperate to generate the pumping effect.

9. A vacuum pump (10) according to at least one of the preceding claims, wherein the exactly one stator disk (20) or the one of the two or more stator disks (20) is the stator disk (20) of a plurality of axially mutually spaced apart stator disks (20) of the stator (12) that is disposed axially closest to the pump inlet (36) and / or wherein, in addition to the exactly one stator disk (20) or the one of the two or more stator disks (20), one or more stator disks (20) of identical design thereto are provided, in each of which the blade plane (26) is disposed axially closer to a pump inlet (36) than the fastening plane (32).

10. A vacuum pump (10) according to at least one of the preceding claims, wherein the exactly one stator disk (20) or the one of the two or more stator disks (20) is axially clamped to the stator (12) with the end section (30) of the fastening section (28).

11. A vacuum pump (10) according to at least one of the preceding claims, wherein a pump housing (38) forming a part of the stator (12) comprises the flange section (42) for establishing a mechanical connection with a recipient and the shoulder section (40) which is axially spaced apart from the pump inlet (36), in particular wherein the connection element is at least one screw (46).

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