Vacuum pump having holweck pump stage formed modularly

Abstract

To improve flexibility of the structure related to characteristic values, such as the exhaust speed and / or compression performance and electric power consumption, in design of a pump.SOLUTION: A vacuum pump 111, in particular, a turbo molecular vacuum pump, includes at least one holweck pump stage having a holweck stator and a holweck rotor. The holweck stator has stator sleeves 10, 169. The stator sleeve has: a fixed end 14 attached to a housing portion 12 in a home position of the vacuum pump; and a free end 14 located at the opposite side of the fixed end in an axial direction. The holweck rotor has a rotor sleeve 163. The rotor sleeve encloses the stator sleeve while forming a holweck gap 173. In the vaccum pump, the stator sleeve is formed by multiple portions.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The invention relates to a vacuum pump, in particular a turbomolecular vacuum pump, also referred to herein simply as pump, according to the preamble of claim 1, which has an inner Holweck pump stage. [Background technology]

[0002] Vacuum pumps are used in various technical fields. Depending on the requirements, the vacuum pump may have one or more pump stages. Generally, Holweck pump stages belong to the type of molecular vacuum pumps, which create a molecular flow by rotating a Holweck rotor relative to a fixed Holweck stator. Basically, the vacuum pump may have one or more Holweck pump stages, where multiple Holweck pump stages can be operated both in series and in parallel with each other. Typically, Holweck pump stages are used in turbomolecular vacuum pumps, where the Holweck pump stage is connected downstream of one or more turbomolecular pump stages in the flow direction.

[0003] A Holbeck pump usually has a Holbeck rotor and a Holbeck stator, where the Holbeck rotor has a rotor shaft on which one or more Holbeck rotor sleeves are concentrically arranged, for example by means of a disk-shaped Holbeck hub. In this case, the Holbeck hub and the Holbeck rotor sleeve can be constructed in one piece or in one piece, whereas alternatively the Holbeck hub and the Holbeck rotor sleeve can be initially separately manufactured parts which are subsequently joined to one another, for example by welding. The Holbeck stator sleeve assigned to the respective Holbeck rotor sleeve has a single or multiple start Holbeck thread and forms a Holbeck gap together with the respective Holbeck rotor sleeve. The gas molecules to be pumped are pumped along the thread from the inlet to the outlet of the respective Holbeck pump stage by the rotational movement of the Holbeck rotor relative to the Holbeck stator. The threads have Holweck channels in the form of helically circumferential grooves defined by the walls of the threads, and gas molecules are pumped in the threads as the rotor sleeve rotates relative to the stator sleeve.

[0004] Furthermore, so-called "folded" Holbeck arrangements are known, in which Holbeck pump stages are arranged concentrically with one another and engage one another internally, so that the pumping directions of radially directly successive Holbeck pump stages are opposite to one another. Two flow-sequential Holbeck pump stages, i.e. a radially outer Holbeck pump stage and a radially inner Holbeck pump stage, therefore have a common Holbeck stator sleeve, which is located radially between the two rotor sleeves and is provided with a Holbeck thread on both sides respectively. The radially outer rotor sleeve may itself be surrounded by an outer stator sleeve in the same way, so that together with the outer rotor sleeve a further Holbeck pump stage is formed. In contrast to the stator sleeve located radially outside the outer rotor sleeve, in the context of this specification the stator sleeve located radially inside the outer rotor sleeve is naturally also referred to as an inner stator sleeve, even if it does not itself surround the inner rotor sleeve.

[0005] Essentially, the Holweck geometry and in particular the configuration of the Holweck thread influence the characteristic values ​​of the respective pump stage, such as the pumping speed and / or compression performance of the Holweck pump stage as well as the power consumption of the pump motor, etc. However, since the Holweck geometry usually does not change over the axial extension length of the Holweck stator sleeve, the characteristic values ​​mentioned can only be adjusted to a limited extent in the pump design. Summary of the Invention [Problem to be solved by the invention]

[0006] The invention is therefore based on the object of providing a vacuum pump as mentioned at the beginning which allows for greater freedom in designing the pump, for example with regard to characteristic values ​​such as pumping speed and / or compression performance as well as power consumption. [Means for solving the problem]

[0007] This problem is solved by a vacuum pump having the features of claim 1, in particular in that the inner or inner located stator sleeve is made from multiple parts.

[0008] The stator sleeve may therefore consist of several sleeve parts arranged axially one after the other or directly adjacent to one another which can be handled separately during production, the individual sleeve parts being able to differ, for example, with regard to the number of threads or the threading formed by the threads, in order to affect the characteristic values ​​mentioned in a precise manner.

[0009] For example, an inner or inwardly located stator sleeve may comprise a first sleeve part having a first end and a second end opposite the first end, and at least one second sleeve part also having a first end and a second end opposite the first end, where the first end of the first sleeve part is attached to a fixed housing part of the vacuum pump and thus forms a fixed end of the stator sleeve, whereas the first end of the second sleeve part is attached to the second end of the first sleeve part, and thus forms a free end of the stator sleeve if no other sleeve part is attached to the second end of the second sleeve part.

[0010] Thus, by virtue of the stator sleeve being composed of a number of sleeve parts, for example a first sleeve part may be distinguished by a thread geometry which differs from the thread geometry of the second sleeve part. Different thread geometries may thus be used for the sleeve parts, in which case a Holweck stator may be constructed as required, so that the pumping speed and / or compression performance of the Holweck pump stage may be modelled appropriately. For example, it is also possible to replace the first sleeve part and / or the second sleeve part with another sleeve part having a different thread geometry, so that the characteristic values ​​of an existing vacuum pump may be changed.

[0011] In so far as the respective different thread geometries have been mentioned above, this relates to the external thread of the stator sleeve and the possibly present internal thread formed by a number of thread grooves defined by the thread sections formed in the stator sleeve and the groove root formed by the stator sleeve, in which case the external thread of the first sleeve part may differ from the external thread of the second sleeve part by at least one thread variable, in which case the at least one thread variable is selected from the group of thread variables consisting of the number of thread sections, the thread pitch, the width of the thread groove, the width of the thread section and the height of the thread section above the groove root.

[0012] In order that the individual sleeve parts can be interchanged with one another or exchanged for other sleeve parts, it can be envisaged according to one embodiment that the first end of the first sleeve part has a first end profile and the first end of the second sleeve part has a first end profile corresponding to the first end profile of the first sleeve part. Similarly, the second end of the first sleeve part can have a second end profile and the second end of the second sleeve part can have a second end profile corresponding to the second end profile of the first sleeve part. In other words, the first end profiles can each be essentially identically shaped and the second end profiles can also each be essentially identically shaped. Thus, when the first sleeve part is attached with its first end to the housing part in place, and therefore based on the fact that the first end profile of the second sleeve part corresponds to the first end profile of the first sleeve part, the second sleeve part can also be attached with its first end profile to the housing part in place, if necessary.

[0013] To further facilitate the interchangeability of the individual sleeve parts, according to another embodiment, it may be further envisaged that the first end of the first sleeve part has a first end profile and the first end of the second sleeve part has a second end profile that is configured complementarily to the first end profile of the first sleeve part. Similarly, the first end of the second sleeve part may have a first end profile and the second end of the first sleeve part may have a second end profile that is configured complementarily to the first end profile of the second sleeve part. Thus, the two sleeve parts can be combined to form a single stator sleeve, since the respective first end profile of one sleeve part fits into the respective second end profile of the other sleeve part.

[0014] Thus, since the first end profile of the first sleeve part is configured complementary to the second end profile of the second sleeve part, instead of the first sleeve part, the second sleeve part can be mounted with its first end profile in the above-mentioned manner in the fixed housing part and the first sleeve part with its first end profile in the second end profile of the second sleeve part. Thus, although in the initial state of the vacuum pump, i.e. the first sleeve part is mounted in the fixed housing part of the vacuum pump and the second sleeve part is mounted at the second end of the first sleeve part, the two sleeve parts can be interchanged in such a way that the second sleeve part is mounted with its first end profile in the fixed housing part and the first sleeve part is mounted with its first end profile in the second end profile of the second sleeve part.

[0015] According to another embodiment, it can be envisaged that each first end profile has an annular first end face and an annular second end face that is axially recessed relative to the annular first end face. Similarly, each second end profile may have an annular first end face and an annular second end face that is axially recessed relative to the annular first end face. In this case, the annular first and second end faces are arranged coaxially with respect to one another and thus form respectively a stepped end profile.

[0016] If the annular first end face of the first end profile surrounds the annular second end face, then in the second end profile the second end face surrounds the first end face due to the fact that the first end profile is configured complementary to the second end profile, which in turn means that the distance between the first end face of the first end profile and the second end face of the second end profile corresponds to the distance between the second end face of the first end profile and the first end face of the second end profile.

[0017] As mentioned above, the respective second end face of each end profile may be axially recessed with respect to the first end face, but since in the first end profile the first end face surrounds the second end face, while in the second end profile the second end face surrounds the first end face, this means that the first end face of the first end profile is connected to the second end face of the first end profile via a cylindrical inner surface, and the first end face of the second end profile is connected to the second end face of the second end profile via a cylindrical outer surface.

[0018] Due to the complementary features of the respective end profiles, the individual sleeve parts can be joined to one another in the manner described above with an exact fit, although according to a preferred embodiment it can be envisaged that the cylindrical outer surface of the second end profile has a slightly larger diameter than the cylindrical outer surface of the first end profile. The two sleeves can thus be joined to one another via a press fit along the cylindrical outer surface of the second end profile and the cylindrical inner surface of the first end profile.

[0019] Alternatively to this, it is equally possible to provide an internal thread along the referred to cylindrical inner surface and an external thread matching the described internal thread along the referred to cylindrical outer surface, so that the individual sleeve portions can be screwed together.

[0020] The invention will now be described, by way of example only, with reference to the drawings in which: [Brief description of the drawings]

[0021] [Figure 1] 1 shows a perspective view of a known turbomolecular pump; [Diagram 2] FIG. 2 shows a bottom view of the turbomolecular pump of FIG. [Diagram 3] 3 shows a cross-sectional view of a turbomolecular pump taken along the section line AA shown in FIG. 2. [Figure 4] 3 shows a cross-sectional view of the turbomolecular pump taken along the section line BB shown in FIG. 2. [Diagram 5] 3 shows a cross-sectional view of a turbomolecular pump taken along section line CC shown in FIG. 2. [Figure 6] FIG. 2 is a schematic cross-sectional view for explaining the configuration of an inner Holweck stator sleeve according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The turbomolecular pump 111 shown in Fig. 1 has a pump inlet 115 surrounded by an inlet flange 113. To the pump inlet 115, in a manner known per se, a recipient, not shown, may be connected. Gas coming from the recipient can be sucked from the recipient via the pump inlet 115 and pumped through the pump to a pump outlet 117. To the pump outlet 117, an auxiliary vacuum pump, for example a rotary vane pump, may be connected.

[0023] The inlet flange 113 forms the upper end of a housing 119 of the vacuum pump 111 in the orientation of the vacuum pump according to Fig. 1. The housing 119 has a lower part 121, on which an electronics housing 123 is arranged laterally. In the electronics housing 123, electrical and / or electronic components of the vacuum pump 111 are accommodated, for example for operating an electric motor 125 (see also Fig. 3) arranged in the vacuum pump. The electronics housing 123 is provided with a number of connections 127 for accessories. Furthermore, a data interface 129 (for example according to the RS485 standard) and a current supply connection 131 are arranged in the electronics housing 123.

[0024] There are also turbomolecular pumps that do not have this type of attached electronics housing, but are connected to external drive electronics.

[0025] A ventilation inlet 133, in particular in the form of a ventilation valve, is provided in the housing 119 of the turbomolecular pump 111. Via the ventilation inlet 133, the vacuum pump 111 can be vented. In the region of the lower part 121, a sealing gas connection 135 (also called purge gas connection) is also arranged. Via the sealing gas connection 135, a purge gas can be fed into a motor chamber 137 in order to protect the electric motor 125 (see, for example, FIG. 3) against the gas pumped by the pump. In the motor chamber 137, the vacuum pump 111 accommodates the electric motor 125. In the lower part 121, two coolant connections 139 are also arranged. In this case, one coolant connection is provided as an inlet for the coolant and the other coolant connection is provided as an exhaust. A coolant can be introduced into the vacuum pump for cooling purposes. The further turbomolecular vacuum pump present (not shown) is operated exclusively air-cooled.

[0026] The underside 141 of the vacuum pump can be used as a base, so that the vacuum pump 111 can be operated vertically with respect to the underside 141. Moreover, the vacuum pump 111 can be fixed to the recipient via the inlet flange 113 and thus operated in a suspended state, so to speak. Furthermore, the vacuum pump 111 can be configured so that it can be operated even when oriented in a different direction than shown in FIG. 1. Vacuum pump configurations are also feasible in which the underside 141 can be arranged not only downwards, but also sideways or upwards. In this case, in principle, any angle is conceivable.

[0027] In particular, other turbomolecular vacuum pumps (not shown) that are present and are larger than the pump shown cannot be operated in a vertical position.

[0028] Various screws 143 are further arranged on the underside 141 shown in Fig. 2. By means of these screws 143, components of the vacuum pump, not specified in detail here, are fixed to one another. For example, a bearing cover 145 is fixed to the underside 141.

[0029] Fastening holes 147 are furthermore arranged in the underside 141. Via the fastening holes 147, the pump 111 can be fixed, for example, to a mounting surface. This is not possible with other existing turbomolecular vacuum pumps (not shown), in particular those larger than the pump shown.

[0030] 2 to 5 show a coolant line 148. In the coolant line 148 a coolant can be circulated which is introduced and discharged via the coolant connection 139.

[0031] As shown in the cross-sectional views of Figures 3 to 5, the vacuum pump has multiple process gas pumping stages for pumping process gas acting on a pump inlet 115 to a pump exhaust 117.

[0032] A rotor 149 is disposed within the housing 119. The rotor 149 has a rotor shaft 153 that is rotatable about a rotation axis 151.

[0033] The turbomolecular pump 111 has a number of turbomolecular pump stages connected in series to provide a pumping action. The turbomolecular pump stages have a number of radially extending rotor blades 155 fixed to the rotor shaft 153 and a number of stator vanes 157 arranged between the rotor blades 155 and fixed within the housing 119. In this case, each of the rotor blades 155 and the adjacent stator vanes 157 forms one turbomolecular pump stage. The stator vanes 157 are held at a desired axial distance from each other by spacer rings 159.

[0034] The vacuum pump further comprises Holweck pump stages arranged radially inside and outside one another and connected in series to provide a pumping action. There are alternative turbomolecular vacuum pumps (not shown) that do not comprise Holweck pump stages.

[0035] The rotor of the Holweck pump stage comprises a rotor hub 161 arranged on the rotor shaft 153 and two Holweck rotor sleeves 163, 165 with cylindrical flanks fixed to and supported by the rotor hub 161. The Holweck rotor sleeves 163, 165 are oriented coaxially with respect to the axis of rotation 151 and engage one another radially. Two Holweck stator sleeves 167, 169 with cylindrical flanks are further provided. The Holweck stator sleeves 167, 169 are likewise oriented coaxially with respect to the axis of rotation 151 and engage one another radially.

[0036] The pumping surfaces of the Holweck pump stages are formed by the lateral surfaces, i.e. by the radially inner and / or outer surfaces of the Holweck rotor sleeves 163, 165 and the Holweck stator sleeves 167, 169. The radially inner surface of the outer Holweck stator sleeve 167 faces the radially outer surface of the outer Holweck rotor sleeve 163, forming a radial Holweck gap 171, and together with this outer surface forms the first Holweck pump stage following the turbomolecular pump. The radially inner surface of the outer Holweck rotor sleeve 163 faces the radially outer surface of the inner Holweck stator sleeve 169, forming a radial Holweck gap 173, and together with this outer surface forms the second Holweck pump stage. The radially inner surface of the inner Holweck stator sleeve 169 opposes the radially outer surface of the inner Holweck rotor sleeve 165 while forming a radial Holweck gap 175, and together with this outer surface forms the third Holweck pump stage.

[0037] The lower end of the Holweck rotor sleeve 163 may be provided with a radially extending channel, through which the radially outer Holweck gap 171 is connected to the central Holweck gap 173. The upper end of the inner Holweck stator sleeve 169 may be provided with a further radially extending channel, through which the central Holweck gap 173 is connected to the radially inner Holweck gap 175. In this way, the multiple mutually interlocking Holweck pump stages are connected in series with each other. The lower end of the radially inner Holweck rotor sleeve 165 may be further provided with a connecting channel 179 leading to the exhaust port 117.

[0038] The pumping surfaces of the Holweck stator sleeves 167, 169 each have a number of Holweck grooves extending in the axial direction and spiraling around the rotation axis 151, while the opposing sides of the Holweck rotor sleeves 163, 165 are smoothly formed and pump the gas for the operation of the vacuum pump 111 forward in the Holweck grooves.

[0039] For the rotatable support of the rotor shaft 153, a rolling bearing 181 is provided in the area of ​​the pump outlet 117 and a permanent magnetic bearing 183 is provided in the area of ​​the pump inlet 115.

[0040] In the region of the rolling bearing 181, the rotor shaft 153 is provided with a conical splash nut 185. The splash nut 185 has an outside diameter that increases towards the rolling bearing 181. The splash nut 185 is in sliding contact with at least one scraping member of the working medium reservoir. In other existing turbomolecular vacuum pumps (not shown), instead of a splash nut, a splash screw may be provided. Since various configurations are thereby possible, the term "splash tip" is also used in the above context.

[0041] The working medium reservoir comprises a number of absorbent discs 187 stacked one above the other, which are impregnated with a working medium for the rolling bearings 181, for example a lubricant.

[0042] During operation of the vacuum pump 111, the working medium is transferred by capillary action from the working medium reservoir via the scraping element to the rotating splash nut 185 and is then forced by centrifugal force along the splash nut 185 towards the increasing outer diameter of the splash nut 185 towards the rolling bearing 181, where it fulfills, for example, a lubrication function. The rolling bearing 181 and the working medium reservoir are enclosed in the vacuum pump by a trough-like insert 189 and a bearing cover 145.

[0043] The permanent magnetic bearing 183 has a rotor-side bearing half 191 and a stator-side bearing half 193. Each of these has a ring stack, which consists of several rings 195, 197 of permanent magnets stacked axially one above the other. The ring magnets 195, 197 face each other forming a radial bearing gap 199, with the rotor-side ring magnet 195 arranged radially outward and the stator-side ring magnet 197 arranged radially inward. The magnetic field present in the bearing gap 199 induces a magnetic repulsion between the ring magnets 195, 197. This repulsion provides a radial support for the rotor shaft 153. The rotor-side ring magnet 195 is supported by a support part 201 of the rotor shaft 153. The support part 201 surrounds the ring magnet 195 radially outward. The stator-side ring magnet 197 is supported by a support part 203 on the stator side. The support part 203 extends through the ring magnet 197 and is suspended on radial struts 205 of the housing 119. Parallel to the axis of rotation 151, the ring magnet 195 on the rotor side is fixed by a cover element 207 connected to the support part 203. The ring magnet 197 on the stator side is fixed in one direction parallel to the axis of rotation 151 by a fixing ring 209 connected to the support part 203 and a fixing ring 211 connected to the support part 203. Between the fixing ring 211 and the ring magnet 197, a disc spring 213 may further be provided.

[0044] An emergency or safety bearing 215 is provided in the magnetic bearing. During normal operation of the vacuum pump, the emergency or safety bearing 215 runs free without contact and only engages if the rotor 149 is displaced too far radially relative to the stator, thus forming a radial stop for the rotor 149, so that a collision between the rotor-side and stator-side structures is prevented. The safety bearing 215 is configured as a non-lubricated rolling bearing and forms a radial gap together with the rotor 149 and / or the stator. The gap ensures that the safety bearing 215 is not engaged during normal pump operation. The safety bearing 215 engages during radial displacement, which is dimensioned to be sufficiently large so that the safety bearing 215 is not engaged during normal operation of the vacuum pump and at the same time is sufficiently small so that a collision between the rotor-side and stator-side structures is prevented in all circumstances.

[0045] The vacuum pump 111 has an electric motor 125 which drives a rotor 149 in rotation. The armature of the electric motor 125 is formed by the rotor 149. A rotor shaft 153 of the rotor 149 extends through a motor stator 217. A permanent magnet assembly may be arranged radially outwardly or embedded in the part of the rotor shaft 153 which extends through the motor stator 217. An intermediate chamber 219 is arranged between the motor stator 217 and the part of the rotor 149 which extends through the motor stator 217. The intermediate chamber 219 has a radial motor gap. Through the motor gap, the motor stator 217 and the permanent magnet assembly may magnetically interact to transmit a driving torque.

[0046] The motor stator 217 is fixed in the housing in a motor chamber 137 provided for the electric motor 125. Via a seal gas connection 135, a seal gas (also called purge gas, which can be, for example, air or nitrogen) can reach the motor chamber 137. Via the seal gas, the electric motor 125 can be protected against process gases, for example against corrosive parts of the process gas. The motor chamber 137 can be evacuated via the pump outlet 117, i.e. a vacuum pressure acts in the motor chamber 137, which is realized at least approximately by an auxiliary vacuum pump connected to the pump outlet 117.

[0047] A so-called labyrinth seal 223, known per se, may furthermore be provided between the rotor hub 161 and the wall 221 which defines the motor chamber 137. This in particular achieves better sealing of the motor chamber 217 with respect to the radially outer Holweck pump stages.

[0048] Hereinafter, the inner Holweck stator sleeve 10 constructed according to the present invention will be described with reference to Fig. 6. The inner Holweck stator sleeve 10 can be assembled to the turbomolecular vacuum pump 111 in place of the illustrated stator sleeve 169. Moreover, in this case, the other structures of the turbomolecular vacuum pump 111 may be kept similar to the basic structure of a Holweck pump stage having three pump stages located inside and outside.

[0049] In the embodiment shown in Fig. 6, the inner stator sleeve 10 has the form of a substantially hollow cylinder with a free end 16 and an axially opposite fixed end 14. The fixed end 14 is attached here to a fixed housing part 12 of the vacuum pump 111, for example by means of an interference fit connection. Although this is not shown here in Fig. 6, the stator sleeve 10 is concentrically surrounded by the rotor sleeve forming a Holweck gap. By that definition, the stator sleeve 10 is an inner or internal stator sleeve 10.

[0050] As can be easily seen from the drawing in FIG. 6, the stator sleeve 10 is constructed in a multi-part or modular manner, and in the embodiment shown here, the stator sleeve 10 is constructed from a hollow cylindrical first sleeve part 18 and a hollow cylindrical second sleeve part 20, although it may be envisaged that the stator sleeve 10 is constructed from three or more sleeve parts, for example three, four or five or more sleeve parts. Although not shown here, the individual sleeve parts 18, 20 each have an external thread, in which case the external thread of the first sleeve part 18 differs from the external thread of the second sleeve part 20 in at least one thread variable. Furthermore, the two sleeve parts 18, 20 may each have a different axial length. The thread variable mentioned may be, for example, the number of threads forming the individual threads, the thread pitch, the width of the thread, the thread width and / or the thread height across the groove base or the outer surface of the respective sleeve part 18, 20.

[0051] The first sleeve part 18 has a first end 22 and a second end 24 located opposite the first end 22. Correspondingly, the second sleeve part 20 has a first end 26 and a second end 28 located opposite the first end 26. In this case, the first end 22 of the first sleeve part 18 is the end of the first sleeve part 18 that is attached to the fixed housing part 12 and thus corresponds to the fixed end 14 of the stator sleeve 10. In contrast, the first end 26 of the second sleeve part 20 is the end of the second sleeve part 20 via which the second sleeve part 20 is attached to the second end 24 of the first sleeve part 20. Correspondingly, the second end 28 of the second sleeve part 20 forms the free end 16 of the stator sleeve 10 in the case where no further sleeve part is axially connected to the second sleeve part 20.

[0052] As can further be seen from Fig. 6, the first end 22, 26 of the first sleeve portion 18 or the second sleeve portion 20, respectively, forms a stepped first end profile 30, which is formed identically to the first end profile 30 of the second sleeve portion 20. Correspondingly, the second end 24, 28 of the first sleeve portion 18 or the second sleeve portion 20, respectively, forms a stepped second end profile 32, which is formed identically to the second end profile 32 of the second sleeve portion 20. Thus, except for the respective external thread configurations and possible axial extensions, the two sleeve portions 18, 20 are essentially formed identically.

[0053] In order to be able to attach the second sleeve part 20 to the first sleeve part 18, the first end profile 30 of the second sleeve part 20 is configured essentially complementary to the second end profile 32 of the first sleeve part 18. Thus, the first end 26 of the second sleeve part 20 fits essentially form-fittingly into the second end 24 of the first sleeve part 18.

[0054] In order that the arrangement of the two sleeve parts 18, 20 can be interchanged as required, the first end profile 30 of the first sleeve part 18 is furthermore formed essentially complementary to the second end profile 20 of the second sleeve part 20. The second sleeve part 20 can thus be attached via its first end profile 30 to the housing part 12 in a fixed position, while in this case the first sleeve part 18 can be attached with its first end profile 30 to the second end profile 32 of the second sleeve part 20.

[0055] As already mentioned, the two end profiles 30, 32 are stepped and each have an annular first end face 34 and an annular second end face 36. The second end face 36 is axially recessed relative to the annular first end face 34. In this case, the annular second end face 36 is the end face of the respective end profile 30, 32 which is axially recessed relative to the first end face 36. However, in the first end profile 30, the annular first end face 34 surrounds the annular second end face 36, whereas in the second end profile 32, the annular second end face 36 surrounds the annular first end face.

[0056] Based on the fact that the radial positions of the two end faces 34, 36 are interchanged at the opposite ends of each sleeve portion 18, 20, the distance between the end face 34 of the first end profile portion 30 and the second end face 36 of the second end profile portion 32 in each sleeve portion 18, 20 is the same as the distance between the second end face 36 of the first end profile portion 30 and the first end face 34 of the second end profile portion 32.

[0057] As a result, based on the stepped configuration of each end profile portion 30, 32 described above, a cylindrical inner surface 38 extends between the first end face 34 of the first end profile portion 30 and the second end face 36 of the first end profile portion 30, while a cylindrical outer surface 40 extends between the first end face 34 of the second end profile portion 32 and the end face 36 of the second end profile portion 32.

[0058] In this case, each cylindrical outer surface 40 may have a certain radial overdimension relative to the respective cylindrical inner surface 38, so that the sleeve portions 18, 20 can be joined to one another by a press-fit connection acting along the two cylindrical surfaces 38, 40. Alternatively to this, each cylindrical inner surface 38 may be designed to be formed with an internal thread and each cylindrical outer surface 40 to be formed with an external thread that matches the internal thread, so that the sleeve portions 18, 20 can be screwed together.

[0059] Based on the configuration of the sleeve portions 18, 20 which are identical or complementary with respect to the respective end profiles 30, 32, these may be interchanged as required, or possibly replaced with suitably configured sleeve portions having other Holweck thread geometries, which allows greater freedom of design in the pump, e.g. with regard to characteristics such as pumping speed and / or compression performance and power consumption. [Explanation of symbols]

[0060] 10 Status Leave 12 Housing parts in place 14 Fixed end 16 Free end 18 First sleeve part 20 Second sleeve part 22 18 first end 24 18 second end 26 20 first end 28 20 second end 30 first end profile 32 Second end profile 34 First end face (annular) 36 Second end face (annular) 38 Cylinder inner surface 40 Cylindrical outer surface 111 Turbomolecular pump 113 Intake flange 115 Pump Inlet 117 Pump exhaust port 119 Housing 121 Lower part 123 Electronics Housing 125 Electric Motor 127 Accessory connection 129 Data Interface 131 Current supply connection 133 Ventilation Intake 135 Seal gas connection 137 Motor Room 139 Coolant Connection 141 Bottom surface 143 Screw 145 Bearing cover 147 Fixed hole 148 Coolant Line 149 Rotor 151 Rotation axis 153 rotor shaft 155 Moving blade 157 Stator blade 159 Spacer ring 161 rotor hub 163 Holbeck Rotor Sleeve 165 Holbeck Rotor Sleeve 167 Holbeck Sterling Sleeve 169 Holbeck Sterling Sleeve 171 Holbeck Gap 173 Holbeck Gap 175 Holbeck Gap 179 Connection Channels 181 Rolling bearings 183 Permanent magnet type magnetic bearing 185 Splash Nut 187 Disc 189 Insert 191 Rotor side bearing half 193 Stator side bearing half 195 Ring Magnet 197 Ring Magnet 199 Bearing clearance 201 Support part 203 Support part 205 Radial Struts 207 Cover Elements 209 Support Ring 211 Fixing ring 213 Disc spring 215 Emergency or safety bearings 217 Motor Stator 219 Intermediate Room 221 Wall 223 Labyrinth Seal

Claims

1. A vacuum pump (111), in particular a turbomolecular vacuum pump (111), at least one Holbeck pump stage having a Holbeck stator and a Holbeck rotor; The Holweck stator comprises a stator sleeve (10, 169) having a fixed end (14) attached to a fixed housing part (12) of the vacuum pump (11) and a free end (16) axially opposite the fixed end (14); A vacuum pump (111) in which the Holweck rotor has a rotor sleeve (163), the rotor sleeve (163) surrounding the stator sleeve (10, 169) while forming a Holweck gap (173), A vacuum pump (111) characterized in that the stator sleeve (10, 169) is formed in a plurality of parts.

2. 2. A vacuum pump (111) according to claim 1, characterized in that the stator sleeve (10, 169) comprises a first sleeve portion (18) having a first end (22) and a second end (24) located opposite the first end (22), and at least one second sleeve portion (20) having a first end (26) and a second end (28) located opposite the first end (26), the first end (22) of the first sleeve portion (18) being attached to the housing portion (12) in a fixed position, and the first end (26) of the second sleeve portion (20) being attached to the second end (24) of the first sleeve portion (18).

3. the first end (22) of the first sleeve portion (18) has a first end profile (30) and the first end of the second sleeve portion (20) has a first end profile (30) corresponding to the first end profile (30) of the first sleeve portion (18); and / or 3. A vacuum pump (111) according to claim 1 or 2, characterized in that the second end (24) of the first sleeve portion (18) has a second end profile (32) and the second end (28) of the second sleeve portion (20) has a second end profile (32) corresponding to the second end profile (32) of the first sleeve portion (18).

4. the first end (22) of the first sleeve portion (18) has a first end profile (30) and the second end (20) of the second sleeve portion (20) has a second end profile (32) that is complementary to the first end profile (30) of the first sleeve portion (18); and / or 4. A vacuum pump (111) according to claim 1, wherein the first end (26) of the second sleeve portion (20) has a first end profile (30) and the second end of the first sleeve portion (18) has a second end profile (32) that is complementary to the first end profile (30) of the second sleeve portion (20).

5. each said first end profile (30) having a first end face (34) and a second end face (36) axially recessed relative to said first end face (34); and / or 5. A vacuum pump (111) according to claim 3 or 4, characterized in that each said second end profile (32) has a first end face (34) and a second end face (36) that is axially recessed with respect to said first end face (34).

6. 6. A vacuum pump (111) according to claim 5, characterized in that the distance between the first end face (34) of the first end profile (30) and the second end face (36) of the second end profile (32) corresponds to the distance between the second end face (36) of the first end profile (30) and the first end face (34) of the second end profile (32).

7. 7. A vacuum pump (111) according to claim 5 or 6, characterized in that the first end face (34) of the first end profile (30) is connected to the second end face (36) of the first end profile (30) via a cylindrical inner surface (38) and the first end face (34) of the second end profile (32) is connected to the second end face (36) of the second end profile (32) via a cylindrical outer surface (40) having a larger diameter than the cylindrical inner surface (38) of the first end profile (30).

8. 8. A vacuum pump (111) according to any one of claims 1 to 7, characterized in that the stator sleeve (10, 169) is formed with an external thread having a plurality of grooves, the grooves being defined by thread sections formed in the stator sleeve (10, 169) and a groove base formed by the stator sleeve (10, 169), and the external thread of the first sleeve part (18) differs from the external thread of the second sleeve part (20) by at least one thread factor, the at least one thread factor being selected from the group of thread factors consisting of number of thread sections, thread pitch, width of the thread groove, width of the thread section and height of the thread section above the groove base.

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