EP3626971A1 - Vacuum pump - Google Patents

Abstract

The invention relates to a vacuum pump, in particular a turbomolecular pump (111), which comprises a vacuum space (V) delimited by a pump housing (119) and a circuit board (241), the pump housing having a connection opening (225) which is closed in a vacuum-tight manner by the circuit board so that the circuit board separates the vacuum chamber from a pressure chamber (D), and the circuit board is a gas barrier (231) spaced apart from the circuit board on the vacuum side.

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 circuit board, and to a method for producing a vacuum pump.

Vacuum pumps are known from the prior art which have a glass bushing with insulated solder connections for carrying out signals from a vacuum chamber into a pressure chamber. With a large number of signals to be carried out, however, a circuit board is much cheaper to carry out as a vacuum. 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 as e.g. are relevant in the semiconductor industry, a more complex glass bushing with solder connections must be used.

Starting from this prior art, it is an object of the present invention to provide a vacuum pump that is more economical to manufacture and more flexible to use.

According to the invention, this object is achieved by a vacuum pump with the features of claim 1 and a method for producing a vacuum pump with the features of claim 13.

A vacuum pump according to the invention, in particular a turbomolecular pump, comprises a vacuum space delimited by a pump housing and also a vacuum chamber Circuit board, the pump housing having 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 chamber, the circuit board being preceded 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 board. This has the advantage that corrosive process gas can be pumped without it coming into contact with the board and damaging it. As a result, the vacuum pump according to the invention has more flexible uses. In the vacuum pump according to the invention, the 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 manufactured more economically.

The gas barrier is at least approximately gas-tight and at least substantially prevents the pumped gas from passing through. It is arranged in the vacuum chamber of the vacuum pump so that the process gas is kept away from the 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 connection connections are accessible for maintenance, modification and / or repair even in the presence of the gas barrier, so that, for example, the circuit board can be easily replaced.

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

Advantageous embodiments of the invention can be found in the subclaims, 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 for casting at least a section of the vacuum space with any geometry and with components that may be included therein. A potting compound as a gas barrier can fill the vacuum space or a section thereof at least approximately gas-tight without the use of additional sealants.

The gas barrier can be formed in various ways depending on the material. For example, a potting compound in a flowable 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 in a section of the vacuum space and expanded there. Both the solid body can have shape memory properties and can be compressed to be introduced into the vacuum space in order to enable independent, passive expansion later on, and an aid or material can be used to perform 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 facing the gas barrier. The other end of the electrical connection conductor can be connected to a motor, an actuator and / or a sensor system of the vacuum pump, so that signals can be transmitted through the gas barrier between the circuit board and the motor, the actuator system and / or the sensor system of the vacuum pump.

The connection of the connection conductor to the circuit board is advantageously a plug connection. This is, especially with a large number of connection conductors, inexpensive and at the same time more convenient to use than soldered connections. In addition, plug 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 connecting conductor can also be attached to the circuit board in a non-detachable manner, in particular it can be soldered on.

The connecting conductor can have an at least approximately gas-tight sheath in the area of the gas barrier, at least in sections, in particular in an end area of the gas barrier. In particular, the connection conductor can be surrounded in regions along its circumference by a material which prevents gas from penetrating into the insulation of the connection conductor or into the interior of the connection conductor. As a result, gas exchange through the gas barrier over the surface of the connection conductor or, if appropriate, over the inside or outside of the insulation of the connection conductor can be prevented even more effectively. Suitable wraps are, for example, shrink sleeves, in particular with an internal adhesive or 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 circuit board-side or pump area-side area of the vacuum space and possibly with 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 of the Pump that defines a pumping area of the vacuum space. In particular, the gas barrier according to this embodiment does not touch a part of the pump housing of the second pump part. 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 pump lower part, the second pump part a pump upper part. The pump area of the vacuum space can include one or more pump stages of the vacuum pump, as well as at least partially include a motor, an actuator system and / or a sensor system of the vacuum pump.

If the gas lock is only arranged in the first pump part without being in contact with the second pump part, this can facilitate the insertion of the gas lock on the one hand, and on the other hand the assembly and / or disassembly of the vacuum pump and thus maintenance, modification and / or repair of the pump make it easier because the pump parts can be handled separately and defective components can be replaced more easily.

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 from the connection opening to a pump region of the vacuum pump through the pump housing. The channel can be dimensioned such that, in addition to the gas barrier, it can accommodate one or more connecting 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 connector of a connecting 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 board mating connectors required can be carried out.

The channel can have an angled or curved area which is filled by the gas barrier. Such a channel arrangement is advantageous in order to keep the gas barrier away from the circuit board and / or the connection connections. The angled or curved area of the channel can act like a siphon in that the gas barrier only fills the curved or angled area, while the areas of the channel or the vacuum space adjoining the gas barrier remain free of the material of the gas barrier. For example, a channel can have a V-shaped or U-shaped section which is filled with the gas barrier up to a certain level, the areas of the channel in front of and / or behind the gas barrier remaining free. In particular, if a potting compound is used, the pump part, which comprises the channel, can be oriented in a potting orientation for the potting step in such a way that the potting 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 lock can be positioned as desired in the operating state of the pump.

According to one embodiment, the angled region of the channel is formed by at least two intersecting bores, in particular blind bores, and / or milling in at least 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 originate from the same surface or from different surfaces of the pump part, the resulting channel being able to extend from the connection opening adjoining the pressure chamber to a pump region of the vacuum pump. Additional bores, blind bores and / or millings can advantageously supplement the course of the channel, so that connecting conductors and / or plug connectors can be received in the channel. Alternatively or additionally, the channel can be formed by introducing separate components, for example by means of elbows or other elements. The angled area of the channel can be angled several times like a labyrinth. In particular, the channel can run in such a way that the direction has to be changed significantly several times if it is crossed. For example, the directions can be at right angles to each other, other angles being possible within the framework of the design. As a result, the channel can in turn be trough-like or siphon-like in some areas, which allows the connection conductor to be passed from the circuit board to the pumping area of the vacuum pump and a gas-tight filling of the channel or a channel section with a gas barrier.

The angled region of the channel can be defined by a surface of the pump housing and an angle piece attached to the pump housing. In particular, the angle piece can be a separate component which is attached to the pump housing and which has at least two sections, the surfaces of which extend at an angle to one another. In particular, the surfaces can enclose a right angle with one another, other angles also being 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 elbow. To accommodate an angled surface of the contra-angle, additional 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 duct can advantageously be used, since only the dimensions of the open duct may have to be large enough to pass a plug connector of a connecting conductor, while the angled region of the duct only has to accommodate the connecting conductor itself, but not the plug. An open channel also provides easy access to all edges that are created during manufacture within the channel, so that they are easily deburred and / or rounded can. This advantageously prevents damage to the connection conductor or its insulation.

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

A space volume of the vacuum area remaining between the gas barrier and the circuit board can, for example, be connected at least approximately neither to a pump area of the vacuum space nor to the pressure space, and is therefore also referred to below as dead space. A pressure difference between the dead space and the adjacent pumping 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 circuit board accordingly does not lead to an immediate pressure adjustment between the dead space and the pumping area of the vacuum space and / or the pressure room. Under certain circumstances, a remaining leakage gas flow, which can be determined on the basis of a leak 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 compensation, which, however, can last for several hours or even several months at low leakage rates can take place.

According to one embodiment, a region of the vacuum space delimited by the gas barrier and the circuit board is connected to a secondary gas source. The secondary gas source advantageously provides, for example, sealing gas, protective gas, inert gas or flood gas in order to create a defined atmosphere within the dead space which is free of corrosive constituents. Such a protective gas atmosphere can effectively prevent undesirable 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 during operation of the vacuum pump could equal that of the pumping area of the vacuum space, for example a gas in the dead space under a higher pressure can slowly diffuse into the pumping area of the vacuum space. When the vacuum pump is subsequently switched off and the pumping area of the vacuum space is flooded, gas can, for example, diffuse back into the dead space again according to 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 bushing. A protective gas atmosphere generated by means of a secondary gas source can advantageously prevent this.

Without a gas barrier, large amounts of protective 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 the 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 already existing in the vacuum pump and / or by a cross-connection to another area floodable by a secondary gas source and / or by a separate connection of the dead space to the secondary gas source.

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

According to one embodiment, a channel with an angled or curved region can be formed in the pump housing, at least one connecting conductor can be laid through the duct, a gas barrier can be formed in the angled or curved region of the channel, the connecting conductor can be connected to the circuit board, and the board can be attached to the pump housing in a vacuum-tight manner.

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

The sequence of the process steps can be varied depending on the specific design of the channel and the other components. If an open duct with an elbow is used, for example, the connecting conductor can first be laid through the open duct before the elbow is installed angled channel is formed. The same applies to alternatives or in addition to the other process steps.

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. 11D

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 accompanying figures. The drawings, the description of the drawings 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 useful further combinations. Each shows schematically:

Fig. 1

a perspective view of a turbomolecular pump;

Fig. 2

a bottom view of the turbomolecular pump of FIG Fig. 1 ;

Fig. 3

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

Fig. 4

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

Fig. 5

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

Fig. 6

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

Figure 7A

a manufacturing sketch for the manufacture of the channel of Fig. 6 ;

Figure 7B

a cross-sectional view of the angled channel of Fig. 6 ;

Figure 7C

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

Fig. 8

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

Figure 9A

a manufacturing sketch for the manufacture of the channel of Fig. 8 ;

Figure 9B

a cross-sectional view of the angled channel of Fig. 8 ;

Figure 9C

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

Fig. 10

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

Figure 11A

a plan view of the lower part of the pump and the elbow Fig. 10 ;

Fig. 11

B is a manufacturing sketch for the manufacture of the open channel of Fig. 10 ;

Figure 11C

a cross-sectional view of the angled channel with elbow of Fig. 10 ;

Figure 11D

a cross-sectional view of the pump base of Fig. 10 in a potting orientation;

Fig. 12

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

In the Fig. 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 in accordance with the orientation of the vacuum pump Fig. 1 the upper end of the pump housing 119 of the vacuum pump 111. The pump housing 119 comprises a pump lower part 121, on which an electronics housing 123 is arranged on the side. 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. Several connections 127 for accessories are provided on the electronics housing 123. In addition, a data interface 129, for example in accordance with the RS485 standard, and a power supply connection 131 are arranged on the electronics housing 123.

A flood inlet 133, in particular in the form of a flood 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 pump lower part 121 there is also a sealing gas connection 135, which is also referred to as a purge gas connection, via which purge gas to protect the electric motor 125 (see, for example, FIG Fig. 3 ) can be brought in front of the gas conveyed by the pump into the engine compartment 137, in which the electric motor 125 is accommodated in the vacuum pump 111. There are also two coolant connections in the pump lower part 121 139 arranged, wherein one of the coolant connections is provided as an inlet and the other coolant connection as an outlet for coolant, which can be passed 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 attached to a recipient via the inlet flange 113 and can thus be operated in a manner of hanging. In addition, the vacuum pump 111 can be designed so that it can also be operated if it is aligned in a different way than in FIG Fig. 1 is shown. Embodiments of the vacuum pump can also be realized, in which the underside 141 cannot be arranged facing downwards, but turned to the side or directed upwards.

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

Fastening bores 147 are also 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 introduced and discharged via the coolant connections 139 can circulate.

Like the sectional views of the Figures 3 to 5 show, the vacuum pump comprises a plurality of 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 rotatable about an axis of rotation 151.

The turbomolecular pump 111 comprises a plurality of turbomolecular pump stages which are connected to one another in a pumping manner with a plurality of radial rotor disks 155 attached 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 one Pump stage. The stator disks 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 have a pumping effect and are connected in series with one another. The rotor of the Holweck pump stages comprises a rotor hub 161 arranged on the rotor shaft 153 and two cylindrical jacket-shaped Holweck rotor sleeves 163, 165 fastened to and supported by the rotor hub 161, which are oriented coaxially to the axis of rotation 151 and nested one inside the other in the radial direction. Furthermore, two cylindrical jacket-shaped Holweck stator sleeves 167, 169 are provided, which are also oriented coaxially to the axis of rotation 151 and are nested one inside the other in the radial direction.

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

At the lower end of the Holweck rotor sleeve 163, a radially extending channel can be provided, via which the radially outer Holweck gap 171 is connected to the central 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 central Holweck gap 173 is connected to the radially inner Holweck gap 175. As a result, the nested Holweck pump stages are connected in series. At the lower end of the radially inner Holweck rotor sleeve 165, a connection channel 179 to the outlet 117 can also be provided.

The aforementioned pump-active surfaces of the Holweck stator sleeves 163, 165 each have a plurality of Holweck grooves running spirally 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 Drive the vacuum pump 111 in the Holweck grooves.

A roller bearing 181 in the area of the pump outlet 117 and a permanent magnet bearing 183 in the area of the pump inlet 115 are provided for rotatably mounting 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 increasing toward the roller bearing 181. The injection nut 185 is in sliding contact with at least one scraper of an operating fluid reservoir. The resource storage includes a plurality of absorbent disks 187 stacked one on top of the other, which are impregnated with an operating medium for the roller bearing 181, for example with a lubricant.

In the operation of the vacuum pump 111, the operating medium is transferred by capillary action from the operating medium storage via the wiper to the rotating spray nut 185 and, as a result of the centrifugal force along the spray nut 185, is conveyed 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 enclosed in the vacuum pump by a trough-shaped insert 189 and the bearing cover 145.

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

An emergency or catch bearing 215 is provided within the magnetic bearing, which runs empty without contact during normal operation of the vacuum pump 111 and only comes into engagement with an excessive radial deflection of the rotor 149 relative to the stator in order to provide a radial stop for the rotor 149 to form, since a collision of the rotor-side structures with the stator-side structures is prevented. The catch 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 catch bearing 215 to be disengaged in normal pumping operation. The radial deflection at which the catch bearing 215 engages is dimensioned large enough that the catch bearing 215 does not engage during normal operation of the vacuum pump, and at the same time is small enough so that the rotor-side structures collide with the stator-side structures under all circumstances is prevented.

The vacuum pump 111 comprises the electric motor 125 for rotatingly driving 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 which extends through the motor stator 217. Between the motor stator 217 and the section of the rotor 149 which extends through the motor stator 217, an intermediate space 219 is arranged which comprises a radial motor gap, via which the motor stator 217 and the permanent magnet arrangement for transmitting the drive torque can magnetically influence one another.

The motor stator 217 is fixed in the pump housing within the motor space 137 provided for the electric motor 125. Via the sealing gas connection 135, a sealing gas, which is also referred to as a purge gas and which can be, for example, air or nitrogen, can get into the engine compartment 137. The electric motor 125 can be protected from process gas, for example from corrosive portions of the process gas, by means of the sealing gas. The engine compartment 137 can also be evacuated via the pump outlet 117, ie in the engine compartment 137 there is at least approximately the vacuum pressure caused by the fore-vacuum pump connected to the pump outlet 117.

A so-called and known labyrinth seal 223 can also be provided between the rotor hub 161 and a wall 221 delimiting the motor space 137, in particular in order to achieve a better seal of the motor space 217 with respect to the radially outside Holweck pump stages.

Fig. 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 space V delimited by the pump housing 119, which is separated from a pressure space D by means of a circuit board 241 as a vacuum bushing. The circuit board 241 is attached in a vacuum-tight manner to the pump housing 119 in the region of a connection opening 225 using an O-ring 243.

The vacuum space V comprises an angled channel 224, in which a gas barrier 231 is arranged, which is arranged 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 casting compound which has a region 229 (9) angled like a siphon. Figure 7B ) of channel 224 is filled gas-tight.

The circuit board 241 is connected to connection conductors 233 which extend through the gas barrier 231 up to an opening 239 to a pump area 240 ( Fig. 8 ) of the turbomolecular pump 111. The connection conductors 233 have plug connectors 235 which are connected to the circuit board 241. The plug connectors 235 and the adjoining sections of the connecting conductors 233 are received in a receiving space 226 of the angled channel 224. At their end facing the pump region 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 potting compound 231 is not in contact with the circuit board 241 or the plug connectors 235, so that the contacts cannot be adversely affected by the gas barrier 231, in particular by the potting compound. The gas barrier 231 and the circuit board 241 thus define an area of the vacuum space V, referred to as dead space T, which is at least substantially non-gas-connected to the pump area 240 and the pressure space D. A secondary gas source (not shown) can be connected to the dead space T, which can allow flooding of the dead space T with a protective gas in order to keep corrosive process gas from the circuit board 241 even more effectively. The pump lower part 121 is oriented as required in the operating state or can be arranged in any orientation as required, since the hardened casting compound 231 remains effective as a gas barrier under all orientations.

The potting compound 231 in the embodiment shown is arranged exclusively in the lower pump part 121 and is not in contact with an upper pump part 249 ( Fig. 8 ) that defines the pumping area 240 of the vacuum space. The pump lower part 121 can therefore advantageously be easily dismantled for service, maintenance and repair purposes and handled separately. 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 for example enables the circuit board 241 to be easily replaced.

7A to 7C outline the manufacture of the first embodiment of the pump lower part 121 Fig. 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 extend from opposite sides of the pump lower part 121 and intersect at an angle of 90 ° in the exemplary embodiment shown. It goes without saying that, depending on the design constraints, other angles are also possible. A first blind bore 227a extends in the pump housing 119 from the side of the designated pressure chamber D and defines the connection opening 225. A second blind bore 227b defines the opening 239 to the pump region 240 of the turbomolecular pump 111. The pump housing 119 has a third blind bore in the region of the connection opening 225 227c, which extends 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 °, with other angles also being possible here.

Figure 7B shows the total 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 pump lower part 121 shown.

The Figure 7C shows the pump lower part 121 during the insertion of the gas barrier 231 in a potting orientation, which in the exemplary embodiment shown rotates the pump lower part 121 in comparison to the operating state Fig. 6 90 ° to the right. Through channel 224 are first Leads 233 are laid, which on the part of the connection opening 225 have plug connectors 235 for connection to the circuit board 241. The dimension of the channel 224 is selected so that the connection conductors 233 and the plug connectors 235 can be implemented. 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 designed as a potting compound which is initially sufficiently flowable to be introduced into the channel 224 by potting and which then hardens there. For potting, the pump lower part 121 is positioned as shown such that the angled area 229 forms the lowest point of the channel 224 in the manner of a siphon. The potting 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 pump area 240 until the channel 224 is sealed gas-tight. The connecting 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 connection connections. The pump lower part 121 remains in the orientation shown until the potting compound 231 has hardened.

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

Fig. 8 shows the pump lower part 121, which has a circuit board 241 as a vacuum feedthrough and an angled channel 224, in which a gas barrier 231 is arranged. Another pump part, here an upper pump part 249, which the Pump region 240 of the turbomolecular pump 111 is defined, is mounted on the pump lower part 121 and sealed with an O-ring arranged in a sealing groove 247.

How Figure 9A shows, the channel 224 is made of two blind holes 227a and 227b, which intersect at an angle of 90 °, wherein other angles can also be selected taking into account the structural conditions. Both blind holes 227a, 227b are made from the same side of the lower pump part 121, here from the side of the pump area 240, so that the holes define an opening 239 to the pump area 240 and a further hole 251 in the pump housing 119. A milling 245 on the opposite side of the pump lower part 121 completes the passage of the angled channel 224 to the side of the connection opening 225. In comparison to the channel 224 from FIG Fig. 6 Here, the connection opening 225 for the circuit board 241 can be made smaller as a vacuum feedthrough, 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 intersecting blind bores 227a and 227b form a region 229 of the channel 224 which is angled in the manner of a siphon.

Figure 9C shows the pump lower part 121 in an orientation during the introduction of a casting compound as a gas barrier 231 in a casting orientation. Since both blind holes 227a, 227b in Figure 9A Are executed from the same side of the pump housing 119, the pump upper part 249 must already be mounted during the casting in order to seal the drilling opening 251 with the casting compound 231. The opening 239 establishes the communication of the channel 224 with the pump region 240 of the turbomolecular pump 111.

In order to cast the channel 224 with a gas barrier 231, the pump lower part 121 and the pump upper part 249 with the connection conductors 233 carried out are placed in such a way that the siphon-like region 229 can be filled with casting compound 231 from the connection opening 225. The drilling opening 251 is also filled with the potting 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 connecting conductors 233 and can be mounted in a vacuum-tight manner over the connection opening 225 of the pump lower part 121, so that the circuit board separates the vacuum space V from the pressure space D. The pump lower part 121 and the pump upper part 249 can then be oriented as intended for the operation of the turbomolecular pump 111, in particular the pump lower part 121 can be oriented downwards and the pump upper part 249 can be oriented upwards ( Fig. 8 ).

A third embodiment of a pump lower part 121 is shown in FIG Fig. 10 shown in cross section, the steps for manufacturing such a pump lower part 121 are in 11A to 11C outlined. The embodiment shown has a channel 224 which is angled several times like a labyrinth. The angled area is limited in some areas by the surface of the pump housing 119, in some areas by an angle piece 259 fastened to the pump housing 119.

Figure 11A shows the pump lower part 121 viewed from the side of the pump region 240 of the turbomolecular pump 111 and the angle piece 259 before assembly. The pump lower part 121 is drilled through with an open channel 253 and additionally has a first recess 255a and a second recess 255b adjoining it for receiving connecting conductors 233. A mounting area is provided for mounting the angle piece 259 on the pump lower 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 angle piece 259 and the pump housing 119.

Figure 11B shows a cross section through the pump lower part 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 connecting conductors 233 or their insulation are not damaged.

As in Figure 11C shown, the open channel 253 as well as the recesses 255a, 255b and the assembled 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 to it. The channel 224 has an angled area 229, which is provided to receive a gas barrier 231, for example a potting compound. Compared to that in Fig. 6 respectively. Fig. 8 In the first and second embodiment of the channel 224 shown, the open channel 253 need not have a dimension over its entire extent that allows the plug connectors 235 to be passed through. Rather, the angled area 229 only has to provide space for the connecting conductors 233, which allows a compact dimension of the channel. 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 pump lower part 121 is positioned in a potting orientation after the connection conductors 233 have been passed through the open channel 253 and the angle piece 259 has been assembled to form the labyrinthine channel 224, so that the angled area 229 is potted from the port opening 225 can be done ( Figure 11D ). The sealing cord 261 seals the area 229 when using a less viscous one Casting compound, but can be omitted for a more viscous casting compound.

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

In order to avoid gas exchange over the inner and / or outer surface of the insulation of the connecting conductors 233 through the sealing compound 231 between the pumping region 240 of the turbomolecular pump 111 and the circuit board 241, the connecting conductors 233 in FIG Fig. 12 in the area of the gas barrier 231, at least in sections, an at least approximately gas-tight casing 265. In particular in the end regions of the gas barrier 231, which are in direct contact with the vacuum region V on the side of the pump region 240 or on the side of the circuit board 241, a gas-tight sheathing 265 prevents gas entry into the surface or insulation of the connecting conductors 233 and thus possible gas passage through the Potting compound 231 along the connection conductor 233. As shown here, a gas-tight sheath 265 can be achieved by means of shrink tubing, in particular shrink tubing with an internal adhesive.

In order to prevent gas exchange via the interior of the connection 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 connection conductor 233 facing away from the circuit board 241, as in FIG Fig. 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 connection

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 gap

173

Holweck gap

175

Holweck gap

179

Connecting channel

181

roller bearing

183

Permanent magnet bearings

185

Spray nut

187

disc

189

commitment

191

half of the bearing on the rotor side

193

stator side bearing half

195

Ring magnet

197

Ring magnet

199

Bearing gap

201

Beam section

203

Beam section

205

radial strut

207

Cover element

209

Support ring

211

Mounting ring

213

Belleville spring

215

Emergency or catch camp

217

Motor stator

219

Space

221

Wall

223

Labyrinth seal

224

channel

225

Connection opening

226

Recording room

227a

first blind hole

227b

second blind hole

227c

third blind hole

229

siphon-like angled area

231

Gas barrier

233

Connection conductor

235

Connectors

237

Sealing groove for circuit board

239

Opening to the pump area

240

Pumping area

241

circuit board

243

O-ring

245

Milling

247

Sealing groove for the upper part of the pump

249

Pump upper part

251

Drill hole

253

open channel

255a

first recess

255b

second recess

257

Sealing groove for contra-angle

259

Elbow

260

Fastening area

261

Sealing cord

262

edge

265

gastight envelope

267

Connection points with motor, actuators and / or sensors

269

Potting compound of the joints

V

Vacuum space

D

Pressure room

T

Dead space

Claims (15)

Vacuum pump, in particular turbomolecular pump (111), comprising a vacuum space (V) delimited 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 chamber (V) from a pressure chamber (D), wherein the circuit board (241) is preceded by a gas barrier (231) spaced apart from the circuit board (241). Vacuum pump (111) according to claim 1,
characterized in that
the gas barrier (231) has a potting compound. Vacuum pump (111) according to claim 1 or 2,
characterized in that
at least one connecting conductor (233) extends through the gas barrier (231) and is connected to the circuit board (241). Vacuum pump (111) according to claim 3,
characterized in that
the connection of the connecting conductor (233) to the circuit board (241) is a plug connection. Vacuum pump (111) according to claim 3 or 4,
characterized in that
the connecting conductor (233) has an at least approximately gas-tight sheath (265) in the region of the gas barrier (231), at least in sections, in particular in an end region of the gas barrier (231). Vacuum pump (111) according to 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 area (240) of the vacuum space (V). Vacuum pump (111) according to 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 communicates with the vacuum space (V). Vacuum pump (111) according to claim 7,
characterized in that
the channel (224) has an angled or curved region (229) which is filled by the gas barrier (231). Vacuum pump (111) according to 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 millings (245). Vacuum pump (111) according to claim 8 or 9,
characterized in that
the angled area (229) of the channel (224) is angled several times like a labyrinth. Vacuum pump (111) according to claim 10,
characterized in that
the angled region (229) of the channel (224) is defined by a surface of the pump housing (119) and an angle piece (259) attached to the pump housing (119). Vacuum pump (111) according to claim 11,
characterized in that
a sealing element (261) is arranged between the angle piece (259) and the pump housing (119). Vacuum pump (111) according to at least one of the preceding claims,
characterized in that
an area of the vacuum space (V) bounded by the gas barrier (231) and the circuit board (241) is connected to a secondary gas source. A method of manufacturing a vacuum pump (111) in which
a vacuum space (V) delimited 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 chamber (V) from a pressure chamber (D), and
a gas barrier (231), which is arranged in front of the circuit board (241) on the vacuum side and is spaced apart from the circuit board (241). A method of manufacturing a vacuum pump (111) according to claim 14,
characterized in that
a channel (224) with an angled or curved region (249) is formed in the pump housing (119),
at least one connecting conductor (233) is laid through the channel (224),
a gas barrier (231) is formed in the angled or curved region (229) of the channel (224),
the connecting conductor (233) is connected to a circuit board (241), and the circuit board (241) is attached to the pump housing (119) in a vacuum-tight manner.

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