EP3626971B1 - Vacuum pump - Google Patents

Description

The invention relates to a vacuum pump, in particular a turbomolecular pump, with a vacuum chamber which is separated from a pressure chamber in a vacuum-tight manner by a plate, and a method for producing a vacuum pump.

Vacuum pumps are known from the prior art which have a glass feedthrough with insulated soldered connections for the passage of signals from a vacuum space into a pressure space. With a large number of signals to be fed through, however, a circuit board as a vacuum feedthrough is much cheaper. A vacuum pump with such a circuit board is also known, but cannot be used when pumping corrosive gases since corrosive process gas could damage the circuit board. For such applications, such as those relevant in the semiconductor industry, a more complex glass feedthrough with soldered connections must be used.

the EP 3 431 769 A1 discloses a vacuum pump with a vacuum chamber which is sealed against a pressure chamber in a vacuum-tight manner by means of a connection board. To avoid electrical flashovers, connection conductors that are connected to the connection board on the vacuum side and their connection points as well as a motor stator of the vacuum pump are surrounded by a casting compound.

Proceeding from this state of the art, it is an object of the present invention to provide a vacuum pump that can be manufactured more economically and used more flexibly.

According to the invention, this object is achieved by a vacuum pump having the features of claim 1 and a method for producing a vacuum pump having the features of claim 14.

A vacuum pump according to the invention, in particular a turbomolecular pump, comprises a vacuum space delimited by a pump housing and a Circuit board, wherein the pump housing has a connection opening which is closed in a vacuum-tight manner by the circuit board, so that the circuit board separates the vacuum space from a pressure space, the circuit board being preceded on the vacuum side by a gas barrier spaced apart from the circuit board.

The invention is based on the general idea of keeping the process gas away from the circuit board. This has the advantage that corrosive process gas can be pumped without it coming into contact with and damaging the circuit board. As a result, the vacuum pump according to the invention has more flexible application options. In the vacuum pump according to the invention, the circuit board can also be used as a vacuum feedthrough when pumping corrosive process gases, which is a simpler and cheaper solution than a glass feedthrough with soldered connections. The vacuum pump according to the invention can thus be produced more economically.

The gas barrier is at least approximately gas-tight and at least essentially prevents the pumped gas from passing through. It is arranged in the vacuum chamber of the vacuum pump in such a way that the process gas is kept away from the circuit board. So that the circuit board and possibly its electrical connection connections are not impaired by the gas barrier, the gas barrier is not in direct contact with the circuit board and/or the connection connections. This also has the advantage that the circuit board and terminal connections are accessible for maintenance, modification and/or repair even in the presence of the gas barrier, so that the circuit board can be easily replaced, for example.

While in the vacuum space in the operating state of the vacuum pump there can be a negative pressure generated by at least one pump stage, the circuit board separates the vacuum space from a pressure space in which For example, atmospheric pressure can prevail. A leakage rate of the circuit board as a vacuum feedthrough can be at least essentially negligible.

Advantageous developments of the invention can be found in the dependent claims, the description and the drawing.

According to one embodiment, the gas barrier of the vacuum pump has a potting compound. This can advantageously be used to encapsulate at least one section of the vacuum space with any desired geometry and with any components included therein. A casting compound as a gas barrier can fill the vacuum space or a section thereof at least approximately gas-tight without the use of additional sealing means.

The gas barrier can be formed in various ways, depending on the material. For example, a potting compound in a free-flowing state can be poured into an area of the vacuum space provided for receiving the gas barrier, where the potting compound then hardens. Gas barriers of a different design can be introduced into the vacuum chamber of the vacuum pump in a suitable manner. For example, the gas barrier of the vacuum pump can have a self-expanding material property. Furthermore, the gas barrier can be introduced as a solid body into a section of the vacuum space and expanded there. The solid body can have shape-memory properties and can be compressed for introduction into the vacuum space in order to enable later independent, passive expansion, or an aid or substance can be used to carry out a forced expansion.

The vacuum pump preferably has at least one connecting conductor which extends through the gas barrier and which is connected to the circuit board, in particular to a side of the circuit board which faces the gas barrier. The other end of the Electrical connection conductor can be connected to a motor, actuators and / or sensors of the vacuum pump, so that signals can be transmitted through the gas barrier between the circuit board and the motor, actuators and / or sensors of the vacuum pump.

Advantageously, the connection between the connecting conductor and the circuit board is a plug-in connection. This is cheap, especially when there are a large number of connection conductors, and at the same time more convenient to use than soldered connections. In addition, plug-in connections are advantageous with regard to assembly, repair and/or maintenance of the vacuum pump, since they can be detached and reconnected without being destroyed. Alternatively, the connection conductor can also be permanently attached to the circuit board, in particular it can be soldered on.

The connection conductor can have an at least approximately gas-tight covering in the area of the gas barrier, at least in sections, in particular in an end area of the gas barrier. In particular, the connecting conductor can be surrounded by a material in some areas along its circumference, which prevents gas from penetrating into the insulation of the connecting conductor or into the interior of the connecting conductor. As a result, gas exchange through the gas barrier via the surface of the connecting conductor or possibly via the inside or outside of the insulation of the connecting conductor can be prevented even more effectively. Shrink tubing, for example, is suitable as the covering, in particular with an internal adhesive, or else other sealants. These can be used in particular in an end region of the gas barrier, i. H. in the areas of the gas barrier that are in direct contact with the board-side or pump-side area of the vacuum space and possibly the gases located therein.

According to one embodiment, the gas barrier is arranged in a first pump part of the pump and is not in contact with a second pump part Pump defining a pumping area of the vacuum space. In particular, according to this embodiment, the gas barrier does not touch a part of the pump housing of the second pump part. In this case, the pump parts can in particular be separate components of the vacuum pump which are connected to one another, for example screwed, in the assembled vacuum pump. The first pump part can be, for example, a lower pump part, and the second pump part can be an upper pump part. The pump area of the vacuum chamber can contain one or more pump stages of the vacuum pump, and also at least partially include a motor, actuators and/or sensors of the vacuum pump.

If the gas barrier is only arranged in the first pump part, without being in contact with the second pump part, this can facilitate the introduction of the gas barrier on the one hand, and on the other hand also the assembly and/or disassembly of the vacuum pump and thus maintenance, modification and/or repair of the pump facilitate, as a separate handling of the pump parts and a simplified replacement of defective assemblies can be done.

According to one embodiment, the gas barrier is arranged in a channel which is formed in the pump housing and communicates with the vacuum space. In particular, the channel can extend through the pump housing from the connection opening to a pumping area of the vacuum pump. The channel can be dimensioned in such a way that, in addition to the gas barrier, it can accommodate one or more connection conductors for connecting the circuit board to a motor, an actuator system and/or a sensor system. The channel can have dimensions that also allow a plug connector of a connection conductor to be passed through for connection to the circuit board. In particular, the channel can be so wide that the diagonal dimensions of the largest mating board connector required can be carried out.

The channel may have an angled or curved area filled by the gas barrier. Such channeling is advantageous in keeping the gas barrier away from the circuit board and/or terminal connections. The angled or curved portion of the duct may act siphon-like in that the gas barrier fills only the curved or angled portion while the portions of the duct or vacuum space adjacent to the gas barrier remain free of the gas barrier material. For example, a duct may have a V-shaped or U-shaped section that is filled with the gas barrier to a certain level, leaving the areas of the duct before and/or behind the gas barrier free. In particular, if a casting compound is used, the pump part, which includes the channel, can be oriented in a casting alignment for the casting operation in such a way that the casting compound only reaches the siphon-like angled or curved area until the channel is completely filled with the gas barrier is. After the casting compound has hardened, the pump part with the gas barrier can be positioned as desired when the pump is in operation.

According to one embodiment, the angled area of the channel is formed by at least two crossing bores, in particular blind bores, and/or millings in at least one part of the pump. In this way, the angled channel can be easily formed in a pump part. The different bores, blind bores and/or millings can emanate from the same surface or from different surfaces of the pump part, with the resultant channel being able to extend from the connection opening adjacent to the pressure chamber to a pump area of the vacuum pump. Additional bores, blind bores and/or millings can advantageously supplement the course of the channel, so that connection conductors and/or plug connectors can be accommodated in the channel. Alternatively or additionally, the channel can be formed by introducing separate components, for example by means of angle pieces or other elements.

The angled area of the channel can be angled multiple times like a labyrinth. In particular, the channel can run in such a way that the direction has to be changed significantly several times when walking through it. In this case, for example, the directions can be at right angles to one another, with other angles being possible within the framework of the structural conditions. As a result, the channel can in turn have a trough-like or siphon-like design in some areas, which allows the connection conductor to be fed through from the circuit board to the pump area of the vacuum pump and the channel or a channel section to be filled in a gas-tight manner with a gas barrier.

The angled portion of the channel may be defined by a surface of the pump housing and an elbow attached to the pump housing. In particular, the elbow can be a separate component which is attached to the pump housing and which has at least two sections whose surfaces extend at an angle to one another. In particular, the surfaces can form a right angle with one another, although other angles are also possible.

For example, an open channel can be arranged in the pump housing, which is developed into a channel with an angled geometry by installing a separate component, in particular an angle piece. To accommodate an angled surface of the angle piece, further bores, blind bores and/or millings can be arranged in the pump housing in addition to the open channel. As a result, a more compact channel can advantageously be used, since only the dimensions of the open channel may have to be large enough to pass through a connector of a connecting conductor, while the angled area of the channel only has to accommodate the connecting conductor itself, but not the plug. An open channel also provides easy access to any edges created within the channel during fabrication for easy deburring and/or rounding be able. As a result, damage to the connecting conductor or its insulation can advantageously be avoided.

A sealing element is advantageously arranged between the angle piece and the pump housing. The sealing element can be an O-ring or a sealing cord, for example. As a result, the angled channel can also be sealed in the area of the separately attached angle piece, so that escaping of the sealing compound during the sealing is prevented, particularly when using a sealing compound as a gas barrier. The sealing element can be omitted when using other types of gas barriers or when using high-viscosity potting compound.

A volume of space in the vacuum area that remains between the gas barrier and the circuit board can, for example, be at least approximately connected neither to a pump area of the vacuum area nor to the pressure area in a gas-carrying manner and is therefore also referred to below as a dead space. A pressure difference between the dead space and the adjacent pump area of the vacuum space separated by the gas barrier and/or a pressure difference between the dead space and the adjacent pressure space separated by the plate does not result in any direct pressure equalization between the dead space and the pump area of the vacuum space and /or the print room. Under certain circumstances, a remaining leakage gas flow, which can be determined on the basis of a leakage rate between the pumping area of the vacuum space and the dead space or between the pressure space and the dead space, can lead to a gradual pressure equalization, which, however, at low leak rates lasts for several hours or even several months can take place.

In one embodiment, a portion of the vacuum space defined by the gas barrier and the circuit board is connected to a secondary gas source.

The secondary gas source advantageously provides, for example, barrier gas, protective gas, inert gas or flood gas in order to create a defined atmosphere within the dead space that is free from corrosive components. Such a protective gas atmosphere can be used to effectively prevent undesired gas diffusion from the pumping area of the vacuum space through the gas barrier into the dead space, even if the gas barrier should have a non-negligible leak rate.

In this case, the pressure in the dead space could equalize that of the pump area of the vacuum space during operation of the vacuum pump, with a gas that is under a higher pressure in the dead space being able to slowly diffuse into the pump area of the vacuum space, for example. If the vacuum pump is then switched off and the pump area of the vacuum space is flooded, gas can, for example, again diffuse back out of the pump area of the vacuum space into the dead space in accordance with the leakage rate of the gas barrier. If the gas diffusing into the dead space still contains traces of corrosive process gases, these could damage the circuit board as a vacuum feedthrough. A protective gas atmosphere generated by means of a secondary gas source can advantageously prevent this.

Without a gas barrier, large amounts of shielding gas would have to flow continuously along the cable connections during and after the operation of the vacuum pump in the direction of the pumping area of the vacuum space in order to ensure adequate protection of the circuit board. In combination with the at least approximately gas-tight gas barrier, the additional consumption of protective gas for the production of a defined atmosphere in the dead space amounts to very small to negligible amounts.

The secondary gas source can be connected to the dead space in various ways, for example by a cross-connection in the form of a bore or a covered channel to another gas inlet of a secondary gas source that already exists in the vacuum pump and/or through a cross connection to another area that can be flooded by a secondary gas source and/or through a separate connection of the dead space to the secondary gas source.

Another object of the invention is a method for producing a vacuum pump. This provides for a vacuum space delimited by a pump housing and a circuit board to be provided, for a connection opening to be formed in the pump housing, for the connection opening to be closed in a vacuum-tight manner by the circuit board so that the circuit board separates the vacuum space from a pressure space, and for a gas barrier to be formed on the vacuum side in front of the circuit board, which is spaced from the board. The advantages mentioned above can be achieved accordingly by the vacuum pump produced in this way.

According to one embodiment, a duct with an angled or curved portion can be formed in the pump housing, at least one lead routed through the duct, a gas barrier formed in the angled or curved portion of the duct, the lead leads connected to the circuit board, and the circuit board must be attached to the pump housing in a vacuum-tight manner.

The channel can be formed in one piece by the pump housing or in multiple pieces by the pump housing and/or additional components, for example angle pieces, sleeve elements or the like.

Depending on the specific configuration of the channel and the other components, the sequence of the method steps can be varied. When using an open duct with an angle piece, for example, the connection conductor can first be routed through the open duct before the angle piece is installed angled channel is formed. The same applies to the other process steps as an alternative or in addition.

Fig. 1

eine perspektivische Ansicht einer Turbomolekularpumpe;

Fig. 2

eine Ansicht der Unterseite der Turbomolekularpumpe von Fig. 1;

Fig. 3

einen Querschnitt der Turbomolekularpumpe längs der in Fig. 2 gezeigten Schnittlinie A-A;

Fig. 4

eine Querschnittsansicht der Turbomolekularpumpe längs der in Fig. 2 gezeigten Schnittlinie B-B;

Fig. 5

eine Querschnittsansicht der Turbomolekularpumpe längs der in Fig. 2 gezeigten Schnittlinie C-C;

Fig. 6

eine Querschnittsansicht eines Pumpenunterteils mit einem abgewinkelten Kanal, einer Gassperre sowie einer Platine als Vakuumdurchführung gemäß einer ersten Ausführungsform;

Fig. 7A

eine Fertigungsskizze zur Herstellung des Kanals von Fig. 6;

Fig. 7B

eine Querschnittsansicht des abgewinkelten Kanals von Fig. 6;

Fig. 7C

eine Querschnittsansicht des Pumpenunterteils von Fig. 6 in einer Vergießausrichtung;

Fig. 8

eine Querschnittsansicht eines Pumpenunterteils mit einem abgewinkelten Kanal, einer Gassperre sowie einer Platine als Vakuumdurchführung gemäß einer zweiten Ausführungsform;

Fig. 9A

eine Fertigungsskizze zur Herstellung des Kanals von Fig. 8;

Fig. 9B

eine Querschnittsansicht des abgewinkelten Kanals von Fig. 8;

Fig. 9C

eine Querschnittsansicht des Pumpenunterteils von Fig. 8 in einer Vergießausrichtung;

Fig. 10

eine Querschnittsansicht eines Pumpenunterteils mit einem abgewinkelten Kanal mit einem Winkelstück, einer Gassperre sowie einer Platine als Vakuumdurchführung gemäß einer dritten Ausführungsform;

Fig. 11A

eine Draufsicht auf das Pumpenunterteil und das Winkelstück aus Fig. 10;

Fig. 11

B eine Fertigungsskizze zur Herstellung des offenen Kanals von Fig. 10;

Fig. 11C

eine Querschnittsansicht des abgewinkelten Kanals mit Winkelstück von Fig. 10;

Fig. 11

D eine Querschnittsansicht des Pumpenunterteils von Fig. 10 in einer Vergießausrichtung;

Fig. 12

eine Querschnittsansicht einer Vakuumpumpe mit einem Pumpenunterteil der dritten Ausführungsform.

The invention is described below by way of example using advantageous embodiments with reference to the attached figures. The drawings, the drawing description and the claims show numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into further meaningful combinations. They show, each schematically:

1

a perspective view of a turbomolecular pump;

2

a view of the bottom of the turbo molecular pump from 1 ;

3

a cross-section of the turbomolecular pump along the in 2 section line AA shown;

4

a cross-sectional view of the turbomolecular pump along the in 2 shown cutting line BB;

figure 5

a cross-sectional view of the turbomolecular pump along the in 2 shown cutting line CC;

6

a cross-sectional view of a pump base with an angled channel, a gas barrier and a circuit board as a vacuum feedthrough according to a first embodiment;

Figure 7A

a manufacturing sketch for the manufacture of the channel from 6 ;

Figure 7B

FIG. 12 is a cross-sectional view of the angled duct of FIG 6 ;

Figure 7C

a cross-sectional view of the pump base of FIG 6 in a potting orientation;

8

a cross-sectional view of a pump base with an angled channel, a gas barrier and a circuit board as a vacuum feedthrough according to a second embodiment;

Figure 9A

a manufacturing sketch for the manufacture of the channel from 8 ;

Figure 9B

FIG. 12 is a cross-sectional view of the angled duct of FIG 8 ;

Figure 9C

a cross-sectional view of the pump base of FIG 8 in a potting orientation;

10

a cross-sectional view of a pump base with an angled channel with an elbow, a gas barrier and a circuit board as a vacuum feedthrough according to a third embodiment;

Figure 11A

shows a top view of the pump base and elbow 10 ;

11

B a manufacturing sketch for the production of the open channel of 10 ;

Figure 11C

FIG. 12 is a cross-sectional view of the angled duct with elbow of FIG 10 ;

11

D is a cross-sectional view of the pump base of FIG 10 in a potting orientation;

12

a cross-sectional view of a vacuum pump with a pump base of the third embodiment.

In the 1 The turbomolecular pump 111 shown comprises a pump inlet 115 surrounded by an inlet flange 113, to which a recipient, not shown, can be connected in a manner known per se. The gas from the recipient can be sucked out of the recipient 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.

The inlet flange 113 forms when the vacuum pump is aligned according to FIG 1 the upper end of the pump housing 119 of the vacuum pump 111. The pump housing 119 comprises a lower pump part 121 on which an electronics housing 123 is arranged laterally. Electrical and/or electronic components of the vacuum pump 111 are accommodated in the electronics housing 123, for example for operating an electric motor 125 arranged in the vacuum pump. A plurality of connections 127 for accessories are provided on the electronics housing 123. In addition, a data interface 129, for example according to the RS485 standard, and a power supply connection 131 are arranged on the electronics housing 123.

A flooding inlet 133, in particular in the form of a flooding valve, is provided on the pump housing 119 of the turbomolecular pump 111, via which the vacuum pump 111 can be flooded. In the area of the lower pump part 121 there is also a sealing gas connection 135, which is also referred to as a flushing gas connection, through which flushing gas to protect the electric motor 125 (see e.g 3 ) before the pumped gas in the engine compartment 137, in which the electric motor 125 is housed in the vacuum pump 111, can be brought. In the lower pump part 121 there are also two coolant connections 139, with one of the coolant connections being provided as an inlet and the other coolant connection being provided as an outlet for coolant which can be fed into the vacuum pump for cooling purposes.

The lower side 141 of the vacuum pump can serve as a standing surface, so that the vacuum pump 111 can be operated standing on the underside 141 . However, the vacuum pump 111 can also be fastened to a recipient via the inlet flange 113 and can thus be operated in a suspended manner, as it were. In addition, the vacuum pump 111 can be designed in such a way that it can also be operated when it is oriented in a different way than in FIG 1 is shown. It is also possible to realize embodiments of the vacuum pump in which the underside 141 cannot be arranged facing downwards but to the side or directed upwards.

At the bottom 141, the in 2 shown, various screws 143 are also arranged, by means of which components of the vacuum pump that are not further specified here are fastened to one another. For example, a bearing cap 145 is attached to the underside 141 .

In addition, fastening bores 147 are arranged on the underside 141, via which the pump 111 can be fastened, for example, to a support surface.

In the Figures 2 to 5 a coolant line 148 is shown, in which the coolant fed in and out via the coolant connections 139 can circulate.

Like the sectional views of the Figures 3 to 5 show, the vacuum pump comprises several process gas pump stages for conveying the process gas present at the pump inlet 115 to the pump outlet 117.

A rotor 149 is arranged in the pump housing 119 and has a rotor shaft 153 which can be rotated about an axis of rotation 151 .

The turbomolecular pump 111 comprises a plurality of turbomolecular pump stages connected in series with one another for pumping purposes, with a plurality of radial rotor disks 155 fastened to the rotor shaft 153 and stator disks 157 arranged between the rotor disks 155 and fixed in the pump housing 119. A rotor disk 155 and an adjacent stator disk 157 each form a turbomolecular pump stage. The stator discs 157 are held at a desired axial distance from one another by spacer rings 159 .

The vacuum pump also comprises Holweck pump stages which are arranged one inside the other in the radial direction and are connected in series with one another for pumping purposes. The rotor of the Holweck pump stages comprises a rotor hub 161 arranged on the rotor shaft 153 and two Holweck rotor sleeves 163, 165 in the shape of a cylinder jacket, fastened to the rotor hub 161 and carried by it, which are oriented coaxially to the axis of rotation 151 and are nested in one another in the radial direction. Also provided are two cylinder jacket-shaped Holweck stator sleeves 167, 169, which are also oriented coaxially with respect to the axis of rotation 151 and are nested in one another when viewed in the radial direction.

The pumping-active surfaces of the Holweck pump stages are formed by the lateral surfaces, ie by 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 lies opposite the radial outer surface of the outer Holweck rotor sleeve 163, forming a radial Holweck gap 171 and forming with it the first Holweck pump stage following the turbomolecular pumps. The radially inner surface of the outer Holweck rotor sleeve 163 faces the radially outer surface of the inner Holweck stator sleeve 169 opposite to form a radial Holweck gap 173 and forms with this a second Holweck pump stage. The radially inner surface of the inner Holweck stator sleeve 169 faces the radially outer surface of the inner Holweck rotor sleeve 165 to form a radial Holweck gap 175 and therewith forms the third Holweck pumping stage.

At the lower end of the Holweck rotor sleeve 163, a radially running channel can be provided, via which the radially outer Holweck gap 171 is connected to the middle Holweck gap 173. In addition, a radially extending channel can be provided at the upper end of the inner Holweck stator sleeve 169, via which the middle Holweck gap 173 is connected to the radially inner Holweck gap 175. As a result, the nested Holweck pump stages are connected in series with one another. Furthermore, a connecting channel 179 to the outlet 117 can be provided at the lower end of the radially inner Holweck rotor sleeve 165 .

The above-mentioned pumping-active surfaces of the Holweck stator sleeves 163, 165 each have a plurality of Holweck grooves running in a spiral shape around the axis of rotation 151 in the axial direction, while the opposite lateral surfaces of the Holweck rotor sleeves 163, 165 are smooth and the gas for operating the Advance vacuum pump 111 in the Holweck grooves.

A roller bearing 181 in the region of the pump outlet 117 and a permanent magnet bearing 183 in the region of the pump inlet 115 are provided for the rotatable mounting of the rotor shaft 153 .

In the area of the roller bearing 181 , a conical spray nut 185 is provided on the rotor shaft 153 with an outer diameter that increases toward the roller bearing 181 . The injection nut 185 is in sliding contact with at least one stripper of an operating fluid store. The resource storage includes a plurality of absorbent discs 187 stacked on top of one another, which are impregnated with an operating medium for the roller bearing 181, for example with a lubricant.

During operation of vacuum pump 111, the operating fluid is transferred by capillary action from the operating fluid reservoir to the rotating spray nut 185 via the scraper and, as a result of the centrifugal force, is conveyed along the spray nut 185 in the direction of the increasing outer diameter of the spray nut 185 to the roller bearing 181, where it e.g. fulfills a lubricating function. The roller bearing 181 and the operating fluid reservoir are surrounded by a trough-shaped insert 189 and the bearing cover 145 in the vacuum pump.

The permanent magnet bearing 183 comprises a bearing half 191 on the rotor side and a bearing half 193 on the stator side, which each comprise a ring stack of a plurality of permanent magnetic rings 195, 197 stacked on top of one another in the axial direction. The ring magnets 195, 197 lie opposite one another, forming a radial bearing gap 199, the ring magnets 195 on the rotor side being arranged radially on the outside and the ring magnets 197 on the stator side being arranged radially on the inside. The magnetic field present in the bearing gap 199 produces magnetic repulsive forces between the ring magnets 195, 197, which cause the rotor shaft 153 to be supported radially. The ring magnets 195 on the rotor side are carried by a support section 201 of the rotor shaft 153, which radially surrounds the ring magnets 195 on the outside. The ring magnets 197 on the stator are carried by a support section 203 on the stator, which extends through the ring magnets 197 and is suspended on radial struts 205 of the pump housing 119 . The ring magnets 195 on the rotor side are fixed parallel to the axis of rotation 151 by a cover element 207 coupled to the carrier section 203 . The stator-side ring magnets 197 are fixed parallel to the axis of rotation 151 in one direction by a fastening ring 209 connected to the support section 203 and a fastening ring 211 connected to the support section 203 . Between the mounting ring 211 and the ring magnet 197, a plate spring 213 can also be provided.

An emergency or safety bearing 215 is provided within the magnetic bearing, which runs idle without contact during normal operation of the vacuum pump 111 and only engages in the event of an excessive radial deflection of the rotor 149 relative to the stator, in order to create a radial stop for the rotor 149 to form since collision of the rotor-side structures with the stator-side structures is prevented. The backup bearing 215 is designed as an unlubricated roller bearing and forms a radial gap with the rotor 149 and/or the stator, which causes the backup bearing 215 to be disengaged during normal pumping operation. The radial deflection at which the backup bearing 215 engages is dimensioned large enough so that the backup bearing 215 does not engage during normal operation of the vacuum pump, and at the same time small enough so that the rotor-side structures collide with the stator-side structures under all circumstances is prevented.

The vacuum pump 111 includes the electric motor 125 for rotating the rotor 149. The armature of the electric motor 125 is formed by the rotor 149, the rotor shaft 153 of which extends through the motor stator 217. A permanent magnet arrangement can be arranged radially on the outside or embedded on the section of the rotor shaft 153 that extends through the motor stator 217 . Between the motor stator 217 and the section of the rotor 149 extending through the motor stator 217 there is an intermediate space 219 which comprises a radial motor gap via which the motor stator 217 and the permanent magnet arrangement can influence each other magnetically for the transmission of the drive torque.

The motor stator 217 is fixed in the pump housing inside the motor room 137 provided for the electric motor 125 . Via the sealing gas connection 135, a sealing gas, which is also referred to as purge gas and which can be air or nitrogen, for example, can get into the engine compartment 137. The electric motor 125 can be protected against process gas, for example against corrosive components of the process gas, via the sealing gas. The engine compartment 137 can also be evacuated via the pump outlet 117 , ie the vacuum pressure produced by the backing pump connected to the pump outlet 117 prevails in the engine compartment 137 at least approximately.

What is known as a labyrinth seal 223 can also be provided between the rotor hub 161 and a wall 221 delimiting the motor compartment 137, in particular in order to achieve better sealing of the motor compartment 217 in relation to the Holweck pump stages located radially outside.

6 shows a first embodiment of a pump lower part 121 of the turbomolecular pump 111 in an assembled operating state. The turbomolecular pump 111 has a vacuum chamber V delimited by the pump housing 119, which is separated from a pressure chamber D by means of a circuit board 241 as a vacuum passage. The circuit board 241 is attached to the pump housing 119 in a vacuum-tight manner in the area of a connection opening 225 using an O-ring 243 .

The vacuum chamber V includes an angled channel 224 in which a gas barrier 231 is arranged, which is upstream of the circuit board 241 on the vacuum side and keeps the process gas away from the circuit board 241 and the connection connections of the circuit board 241 . In the exemplary embodiment shown, the gas barrier 231 is a potting compound which has a siphon-like angled area 229 ( Figure 7B ) of the channel 224 in a gas-tight manner.

The board 241 is connected to leads 233 which extend through the gas barrier 231 to an opening 239 to a pumping area 240 ( 8 ) of the turbomolecular pump 111 extend. The connection conductors 233 have plug connectors 235 which are connected to the circuit board 241 . The plug-in connector 235 and the sections of the connecting conductors 233 adjoining it are received in a receiving space 226 of the angled channel 224 . At their end facing the pump area 240 , the connection conductors 233 can be connected to a motor, an actuator system and/or a sensor system of the turbomolecular pump 111 .

The casting compound 231 is not in contact with the circuit board 241 or the plug connectors 235, so that the contacts cannot be impaired by the gas barrier 231, in particular by the casting compound. The gas barrier 231 and the circuit board 241 thus define a region of the vacuum space V referred to as a dead space T, which is at least essentially not connected to the pump region 240 and the pressure space D in a gas-conducting manner. A secondary gas source (not shown) can be connected to the dead space T, which can allow the dead space T to be flooded with a protective gas in order to keep corrosive process gas away from the circuit board 241 even more effectively. In the operating state, the lower pump part 121 is aligned as required or can be arranged in any orientation as required, since the hardened casting compound 231 remains effective as a gas barrier in all orientations.

In the embodiment shown, the casting compound 231 is arranged exclusively in the pump lower part 121 and is not in contact with a pump upper part 249 ( 8 ) that defines the pumping region 240 of the vacuum space. Therefore, the lower pump part 121 can advantageously be dismantled in an uncomplicated manner and handled separately for service, maintenance and repair purposes. Additional flexibility in the assembly and disassembly of the turbomolecular pump 111 results from the fact that the connection connections of the circuit board 241 are designed to be pluggable, which enables the circuit board 241 to be easily replaced, for example.

Figures 7A to 7C outline the production of the first embodiment of the pump lower part 121 6 . For reasons of clarity, other components of the turbomolecular pump 111 arranged in the pump lower part 121 are not shown.

Figure 7A shows that the section of the channel 224 provided for receiving the gas barrier 231 is made of two intersecting blind bores 227a and 227b, which emanate from opposite sides of the lower pump part 121 and intersect at an angle of 90° in the exemplary embodiment shown. It goes without saying that, depending on the structural boundary conditions, other angles can also be considered. A first blind hole 227a starts in the pump housing 119 from the side of the designated pressure chamber D and defines the connection opening 225. A second blind hole 227b defines the opening 239 to the pumping area 240 of the turbomolecular pump 111. The pump housing 119 has a third blind hole in the area of the connection opening 225 227c, which expands the channel 224 by a receiving space 226 for receiving electrical or electronic connection components. In the exemplary embodiment shown, the third and first blind bores 227c, 227a intersect at an angle of 45°, although other angles are also possible here.

Figure 7B shows the overall cross section of the resulting channel 224. In the area of the intersecting first and second blind bores 227a, 227b, the channel 224 has an area with an angled contour 229, which is oriented to the right in the orientation of the lower pump part 121 shown.

the Figure 7C shows the lower pump part 121 during the introduction of the gas barrier 231 in a casting orientation, which in the exemplary embodiment shown involves a rotation of the lower pump part 121 compared to the operating state 6 corresponds to 90° to the right. Through the channel 224 are first Connection conductors 233 are laid, which have plug connectors 235 for connection to the circuit board 241 on the part of the connection opening 225 . The dimension of the channel 224 is chosen so that the connection conductor 233 and the plug connector 235 can be passed through. A sealing groove 237 is provided for receiving the O-ring 243 for vacuum-tight mounting of the circuit board 241.

In the exemplary embodiment shown, the gas barrier 231 is in the form of a casting compound which is initially sufficiently free-flowing to be introduced into the channel 224 by casting and which then hardens there. For potting, the lower pump part 121 is positioned, as shown, in such a way that the angled area 229 forms the lowest point of the channel 224 in the manner of a siphon. The sealing compound 231 is introduced into the siphon-like area 229 of the channel 224 through the connection opening 225 and/or the opening 239 to the pumping area 240 until the channel 224 is sealed gas-tight. In this case, the connection conductors 233 are cast in the casting compound 231 . The areas in front of and behind the potting compound remain free of the gas barrier 231, so that the potting compound does not come into contact with the circuit board 241 or its connections. The lower pump part 121 remains in the orientation shown until the sealing compound 231 has hardened.

8 shows a second embodiment of a pump base 121 of a turbomolecular pump 111 in an assembled operating state and Figures 9A to 9C outline the production of the second embodiment. The second embodiment is the in 6 The first embodiment shown is largely similar, which is why the differences between the embodiments will be discussed in particular below.

8 shows the lower pump part 121, which has a circuit board 241 as a vacuum passage and an angled channel 224 in which a gas barrier 231 is arranged. Another pump part, here a pump shell 249, the Defined pumping area 240 of the turbomolecular pump 111 is mounted on the pump base 121 and sealed with an O-ring arranged in a sealing groove 247 .

As Figure 9A shows, the channel 224 is made of two blind bores 227a and 227b, which intersect at an angle of 90°, with other angles also being able to be selected taking into account the structural conditions. Both blind bores 227a, 227b are executed from the same side of the lower pump part 121, here from the side of the pump area 240, so that the bores define an opening 239 to the pump area 240 and a further bore opening 251 in the pump housing 119. A milling 245 on the opposite side of the pump base 121 completes the implementation of the angled channel 224 to the side of the connection opening 225. Compared to the channel 224 of FIG 6 the connection opening 225 for the circuit board 241 as a vacuum passage can be made smaller here, since the milling 245 is at a right angle to the surface of the pump housing 119.

Figure 9B shows the overall cross section of the resulting channel 224. The crossing blind bores 227a and 227b form a siphon-like angled region 229 of the channel 224.

Figure 9C 12 shows the pump base 121 in an orientation during the introduction of a potting compound as a gas barrier 231 in a potting orientation. Since both blind holes 227a, 227b in Figure 9A are carried out from the same side of the pump housing 119, the pump upper part 249 must already be installed during the casting in order to seal the bore opening 251 with the casting compound 231. The opening 239 establishes the communication of the channel 224 with the pumping area 240 of the turbomolecular pump 111 .

To encapsulate the channel 224 with a gas barrier 231, the lower pump part 121 and the upper pump part 249 with the connecting conductors 233 passed through are placed in such a way that the siphon-like angled region 229 can be filled with sealing compound 231 from the connection opening 225. The drilled opening 251 is also filled with the casting compound 231 and sealed by contact with the pump upper part 249 .

After the casting compound 231 has hardened, the circuit board 241 can be connected to the plug connectors 235 of the connection conductors 233 and mounted in a vacuum-tight manner over the connection opening 225 of the lower pump part 121, so that the circuit board separates the vacuum space V from the pressure space D. The lower pump part 121 and the upper pump part 249 can then be aligned as intended for the operation of the turbomolecular pump 111; in particular, the lower pump part 121 can be aligned downwards and the upper pump part 249 can be aligned upwards ( 8 ).

A third embodiment of a pump base 121 is in 10 shown in cross section, the steps for manufacturing such a lower pump part 121 are in Figures 11A to 11C sketched. The embodiment shown has a channel 224 which is labyrinthine multiple angles. The angled area is partially delimited by the surface of the pump housing 119, partially by an angle piece 259 fastened to the pump housing 119.

Figure 11A shows the lower pump part 121 in a top view viewed from the side of the pumping area 240 of the turbomolecular pump 111, as well as the angle piece 259 before assembly. The lower pump part 121 has an open channel 253 drilled through it and, adjoining it, also has a first cutout 255a and a second cutout 255b for accommodating connection conductors 233 . There is a fastening area for mounting the angle piece 259 on the lower pump part 121 260 provided. A sealing groove 257 surrounds the open channel 253 and the recesses 255a, 255b so that a sealing element 261 can be arranged between the elbow 259 and the pump housing 119.

Figure 11B shows a cross section through the pump base 121 with the open channel 253 and the recesses 255a, 255b. Due to the open design, all edges 262 are easily accessible for processing. In particular, they can be deburred or rounded off so that the connection conductors 233 or their insulation are not damaged.

As in Figure 11C shown, the open channel 253 and the recesses 255a, 255b and the mounted angle piece 259 form a labyrinthine channel 224, the walls of which are formed by the pump housing 119 and the angle piece 259 attached thereto. The channel 224 has an angled portion 229 intended to receive a gas barrier 231, such as a potting compound. Compared to the in 6 respectively. 8 In the first and second embodiment of the channel 224 shown, the open channel 253 does not have to have a dimension over its entire extension that allows the connector 235 to be passed through. Rather, the angled area 229 only has to provide space for the connecting conductors 233, which allows the channel to have compact dimensions. A sealing cord 261 guided in the sealing groove 257 between the angle piece 259 and the pump housing 119 seals the channel 224 .

For potting with a potting compound as a gas barrier 231, the lower pump part 121 is positioned in a potting orientation after the connection conductor 233 has been passed through the open channel 253 and the angle piece 259 has been installed to form the labyrinthine channel 224, so that the potting of the angled area 229 starts from the connection opening 225 can be done ( Figure 11D ). The sealing cord 261 seals the area 229 when using a less viscous cord Potting compound from, but can be omitted for a higher viscosity potting compound.

After the casting compound 231 has hardened, the connecting conductors 233 can be connected to the circuit board 241 by means of the plug connector 235, the circuit board 241 can be mounted in a vacuum-tight manner on the pump housing 119 via the connection opening 225 and the lower pump part 121 can be aligned as intended for the operation of the turbomolecular pump 111 and connected to a pump head 249 of the pump.

In order to avoid gas exchange via the inner and/or outer surface of the insulation of the connecting conductors 233 through the potting compound 231 between the pumping region 240 of the turbomolecular pump 111 and the circuit board 241, the connecting conductors 233 in 12 in the area of the gas barrier 231, at least in sections, an at least approximately gas-tight casing 265. Particularly in the end areas of the gas barrier 231, which are in direct contact with the vacuum area V on the side of the pump area 240 or on the side of the circuit board 241, a gas-tight cover 265 prevents gas from entering the surface or insulation of the connection conductor 233 and thus a possible gas passage through the Casting compound 231 along the connection conductor 233. As shown here, a gas-tight envelope 265 can be achieved by shrink tubing, in particular shrink tubing with internal adhesive.

In order to prevent gas exchange via the interior of the connecting conductors 233, the connection points 267 to a motor, an actuator system and/or a sensor system of the turbomolecular pump 111 can also be embedded in a casting compound 269 at the end of the connecting conductors 233 facing away from the circuit board 241, as in 12 is shown.

Reference List

111

turbomolecular pump

113

inlet flange

115

pump inlet

117

pump outlet

119

pump housing

121

pump base

123

electronics housing

125

electric motor

127

accessory port

129

data interface

131

power connector

133

flood inlet

135

sealing gas connection

137

engine compartment

139

coolant connection

141

bottom

143

screw

145

bearing cap

147

mounting hole

148

coolant line

149

rotor

151

axis of rotation

153

rotor shaft

155

rotor disc

157

stator disc

159

spacer ring

161

rotor hub

163

Holweck rotor sleeve

165

Holweck rotor sleeve

167

Holweck stator sleeve

169

Holweck stator sleeve

171

Holweck fissure

173

Holweck fissure

175

Holweck fissure

179

connecting channel

181

roller bearing

183

permanent magnet bearing

185

injection nut

187

disc

189

mission

191

rotor-side bearing half

193

stator bearing half

195

ring magnet

197

ring magnet

199

bearing gap

201

carrier section

203

carrier section

205

radial strut

207

cover element

209

support ring

211

mounting ring

213

disc spring

215

Emergency or catch camp

217

motor stator

219

space

221

wall

223

labyrinth seal

224

channel

225

port opening

226

recording room

227a

first blind hole

227b

second blind hole

227c

third blind hole

229

siphon-like angled area

231

gas lock

233

connection conductor

235

connector

237

Sealing groove for circuit board

239

Opening to pump area

240

pump area

241

circuit board

243

O ring

245

milling

247

Sealing groove for the upper part of the pump

249

pump top

251

drill hole

253

open channel

255a

first recess

255b

second recess

257

Sealing groove for elbow

259

elbow

260

mounting area

261

sealing cord

262

edge

265

gas-tight envelope

267

Connection points with motor, actuators and/or sensors

269

sealing compound of the connection points

V

vacuum space

D

pressure room

T

dead space

Claims (15)

1. A vacuum pump, in particular a turbomolecular pump (111), comprising

   a vacuum space (V) bounded by a pump housing (119); and

   a circuit board (241),

   wherein the pump housing (119) has a connection opening (225) which is closed in a vacuum-tight manner by the circuit board (241) so that the circuit board (241) separates the vacuum space (V) from a pressure space (D),

   wherein the vacuum pump is characterized in that a gas barrier (231) spaced apart from the circuit board (241) is arranged in front of the circuit board (241) at the vacuum side.
2. A vacuum pump (111) in accordance with claim 1,
   characterized in that
   the gas barrier (231) has a casting compound.
3. A vacuum pump (111) in accordance with claim 1 or claim 2, characterized in that
   at least one connection conductor (233) extends through the gas barrier (231) and is connected to the circuit board (241).
4. A vacuum pump (111) in accordance with claim 3,
   characterized in that
   the connection of the connection conductor (233) to the circuit board (241) is a plug-in connection.
5. A vacuum pump (111) in accordance with claim 3 or claim 4, characterized in that
   the connection conductor (233) has an at least approximately gas-tight sleeve (265) in the region of the gas barrier (231) at least in sections, in particular in an end region of the gas barrier (231).
6. A vacuum pump (111) in accordance with at least one of the preceding claims,
   characterized in that
   the gas barrier (231) is arranged in a first pump part (121) of the vacuum pump (111) and is not in contact with a second pump part (249) of the vacuum pump (111) which defines a pump region (240) of the vacuum space (V).
7. A vacuum pump (111) in accordance with at least one of the preceding claims,
   characterized in that
   the gas barrier (231) is arranged in a channel (224) which is formed in the pump housing (119) and which communicates with the vacuum space (V).
8. A vacuum pump (111) in accordance with claim 7,
   characterized in that
   the channel (224) has an angled or curved region (229) which is filled by the gas barrier (231).
9. A vacuum pump (111) in accordance with claim 8,
   characterized in that
   the angled region (229) of the channel (224) is formed by at least two intersecting bores, in particular blind bores (227a, 227b, 227c), and/or milled portions (245).
10. A vacuum pump (111) in accordance with claim 8 or claim 9, characterized in that
    the angled region (229) of the channel (224) is angled a multiple of times in a labyrinthine manner.
11. A vacuum pump (111) in accordance with claim 10,
    characterized in that
    the angled region (229) of the channel (224) is defined by a surface of the pump housing (119) and by an angular piece (259) fastened to the pump housing (119).
12. A vacuum pump (111) in accordance with claim 11,
    characterized in that
    a sealing element (261) is arranged between the angular piece (259) and the pump housing (119).
13. A vacuum pump (111) in accordance with at least one of the preceding claims,
    characterized in that
    a region of the vacuum space (V) bounded by the gas barrier (231) and the circuit board (241) is connected to a secondary gas source.
14. A method of manufacturing a vacuum pump (111), in which a vacuum space (V) bounded by a pump housing (119) and a circuit board (241) are provided,
    a connection opening (225) is formed in the pump housing (119),
    the connection opening (225) is closed in a vacuum-tight manner by the circuit board (241) so that the circuit board (241) separates the vacuum space (V) from a pressure space (D), and
    a gas barrier (231) is formed which is arranged in front of the circuit board (241) at the vacuum side and which is spaced apart from the circuit board (241).
15. A method of manufacturing a vacuum pump (111) in accordance with claim 14, characterized in that

    a channel (224) having an angled or curved region (249) is formed in the pump housing (119),

    at least one connection conductor (233) is laid through the channel (224), a gas barrier (231) is formed in the angled or curved portion (229) of the channel (224),

    the connection conductor (233) is connected to a circuit board (241), and the circuit board (241) is attached in a vacuum-tight manner to the pump housing (119).

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