JP7092825B2 - Vacuum pump - Google Patents

Description

The present invention relates to a vacuum pump including a vacuum chamber that is vacuum-tightly separated from the pressure chamber by a board, particularly a turbo molecular pump, and a method for manufacturing the vacuum pump.

In the prior art, vacuum pumps having a glass feedthrough with an insulated brazing junction for conducting a signal from a vacuum chamber to a pressure chamber are known. However, when there are many signals to be conducted, the board is much cheaper than vacuum feedthrough. Vacuum pumps with such boards are also known, but cannot be used when pumping corrosive gas. This is because corrosive process gases can damage the board. Thus, for this type of application, for example , as is important in the semiconductor industry, more expensive glass feedthroughs with braids must be used.

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

According to the present invention, this problem is solved by a method for manufacturing a vacuum pump having the feature of claim 1 and a vacuum pump having the feature of claim 14 .

The vacuum pump according to the present invention, particularly a turbo molecular pump, comprises a vacuum chamber defined by a pump housing and a board, the pump housing has a connection opening, and the connection opening is vacuum tightly closed by the board. This allows the board to separate the vacuum chamber from the pressure chamber, making the vacuum chamber or part of the vacuum chamber airtight and having a gas barrier in front of the board on the vacuum side to prevent corrosive gas from coming into contact with the board. , Are provided apart from the board.

The present invention is based on the general idea of isolating process gas from the board. The advantage is that corrosive process gas can be pumped without it coming into contact with the board and damaging the board. As a result, the vacuum pump according to the present invention has more flexible usability. In the vacuum pump according to the present invention, the board can also be used as a vacuum feedthrough when pumping a corrosive process gas, which is a simpler and cheaper means than a glass feedthrough having a brazing junction. Therefore, the vacuum pump according to the present invention can be manufactured more economically.

The gas barrier is at least nearly airtight and at least substantially blocks the passage of pumped gas. The gas barrier is arranged in the vacuum chamber of the vacuum pump so that the process gas is isolated from the board. The gas barrier is not in direct contact with the board and / or the connection joints so that the board and , in some cases, the electrical connection joints of the board are not compromised by the gas barrier. Further, according to its advantages, the board and connection joints are accessible for maintenance, modification and / or repair even in the presence of gas barriers, so that the board can be easily replaced, for example . Wear.

While there can be a vacuum generated by at least one pump stage in the vacuum chamber in the operating state of the vacuum pump, the board separates the vacuum chamber from, for example , a pressure chamber in which atmospheric pressure can act, as a feedthrough. .. The leakage rate of the board as a vacuum feedthrough is at least virtually negligible .

The advantageous configuration of the present invention is evident from the dependent claims, the specification and the drawings.

According to one embodiment, the gas barrier of the vacuum pump comprises a sealing material. The encapsulating material can preferably be used to inject into at least a portion of the vacuum chamber with any geometric shape and optionally with components enclosed therein. The encapsulating material as a gas barrier can fill the vacuum chamber or part of the vacuum chamber at least almost airtightly without the use of additional sealing means.

The gas barrier can be formed in various forms depending on the material. For example , the encapsulating material, in a fluid state, can be poured into a region of the vacuum chamber provided to accommodate the gas barrier, where the encapsulating material is subsequently cured. Each gas barrier formed in another form can be introduced into the vacuum chamber of the vacuum pump in an appropriate manner. For example , the gas barrier of a vacuum pump may have self-expanding material properties. In addition, the gas barrier can be introduced as a solid into a portion of the vacuum chamber where it can expand . In this case, the solid has shape memory properties and is compressible for introduction into a vacuum chamber, which not only allows for its own passive expansion later, but also as an auxiliary means. Can use an adjunct, which allows forcible swelling.

Preferably, the vacuum pump has at least one connecting conductor, which extends through the gas barrier and is connected to the board, in particular the side of the board facing the gas barrier. Since the other end of the electrical connection conductor can be connected to the vacuum pump motor, actuator system and / or sensor system, the signal is passed through the gas barrier to the board and vacuum pump motor, actuator system and / or . It can be transmitted to and from the sensor system.

Preferably, the connection between the connecting conductor and the board is a plug-in connection. This is cheaper, especially when there are a large number of connecting conductors, and at the same time is more comfortable to handle than waxed joints. In addition, plug-in connections are advantageous for vacuum pump assembly, repair and / or maintenance. This is because the plug-in connection can be broken and reconnected without being destroyed. Alternatively, the connecting conductors can be irreversibly attached to the board, and in particular the connecting conductors can be brazed.

The connecting conductor may have at least a nearly airtight covering in the area of the gas barrier, at least in part, especially in the edge area of the gas barrier. In particular, the connecting conductor may be partially surrounded along its circumference by an insulator of the connecting conductor or a material that blocks the entry of gas into the interior of the connecting conductor. This can more effectively prevent gas exchange through the surface of the connecting conductor or , in some cases, inside or outside the insulator of the connecting conductor through the gas barrier. As the covering, for example , a shrinkable tube having an inner adhesive or another sealing means is suitable. The shrink tube or other sealing means is in direct contact with, in particular, the end region of the gas barrier, i.e. the region of the vacuum chamber, on the board side or pumping region side, and in some cases with the gas present therein. Can be used in areas of contact, gas barriers.

According to one embodiment, the gas barrier is located in the first pump portion of the pump and is not in contact with the second pump portion of the pump that defines the pumping region of the vacuum chamber. In particular, the gas barrier does not come into contact with a portion of the pump housing of the second pump portion according to the present embodiment. In this case, the pump portion can be a separate component of the vacuum pump, eg screwed together, in particular in the assembled vacuum pump. The first pump portion may be, for example , the lower part of the pump and the second pump portion may be the upper part of the pump. The pumping region of the vacuum chamber may include one or more pump stages of the vacuum pump and may at least partially include the motor, actuator system and / or sensor system of the vacuum pump.

If the gas barrier is located only in the first pump section without contacting the second pump section, this will facilitate the introduction of the gas barrier on the one hand and the assembly and / or vacuum pump assembly on the other hand. Or it can be easily disassembled, and thus the maintenance, modification and / or repair of the pump. This is because the pump parts can be handled separately and the failed structure group can be easily replaced.

According to one embodiment, the gas barrier is located in a channel that is formed in the pump housing and communicates with the vacuum chamber. In particular, the channel can extend from the connection opening of the vacuum pump through the pump housing to the pumping area. The channel may be dimensioned to accommodate one or more connecting conductors for connecting the board to the motor, actuator system and / or sensor system, which is in addition to the gas barrier. The channel may have dimensions that also allow continuity of the connector of the connecting conductor for connecting to the board. In particular, the channel may have a width that allows the diagonal dimensions of the largest board-compatible connector required to be conductive.

The channel may have a curved or curved region, which region is filled by a gas barrier. Such a channel arrangement structure is advantageous for isolating the gas barrier from the board and / or the connection joint. The bent or curved region of the channel fills only the curved or bent region of the gas barrier, while the region of the channel or vacuum chamber adjacent to the gas barrier remains free from the material of the gas barrier. By being there, it can act like a siphon. For example , the channel is filled to a certain level by a gas barrier, in this case having a V-shaped or U-shaped portion of the channel where the front and / or back regions of the gas barrier remain open. You can do it . In particular, when encapsulation material is used, due to the working operation of injection, the pump portion containing the channel reaches only the region where the encapsulation material is siphonally bent or curved, and the channel is a gas barrier all around. Can be oriented in the injection direction until filled with. After the encapsulation material has hardened, the pump portion with the gas barrier can be arbitrarily positioned in the operating state of the pump.

According to one embodiment, the bent region of the channel is formed in at least a portion of the pump by at least two intersecting perforations, in particular bag holes and / or milled parts. In this way, the bent channel can be easily formed in the pump portion. The various perforations, pouches and / or milled parts may start from the same surface or different surfaces of the pump part, in which case the resulting channel will be connected adjacent to the pressure chamber. It can extend from the opening towards the pumping area of the vacuum pump. Additional perforations, bag holes and / or milled parts can suitably capture channel extension so that connecting conductors and / or connectors can be accommodated in the channel. Alternatively or additionally, the channel can be formed , for example , by introducing a separate component with an angle member or other element.

The bent region of the channel can be bent multiple times in a labyrinth-like manner. Especially when through is expected, multiple directions must be changed significantly and the channel can extend as such. In this case, for example , the directions may be at right angles to each other, in which case different angles are possible within the framework of structural circumstances. This can also form the channel in part again in a tank or siphon shape, which allows conduction of the connecting conductor from the board to the pumping region of the vacuum pump, and the channel or by gas barrier. Airtight filling of the channel portion is possible.

The bent region of the channel can be defined by the surface of the pump housing and an angle member fixed to the pump housing. In particular, the angle member can be a separate component attached to the pump housing and has at least two parts whose surfaces extend at an angle to each other. In particular, the surfaces can form right angles to each other, but different angles are possible.

For example , an open channel can be placed within the pump housing, which is transformed into a channel with a curved geometry by assembling separate components, in particular angle members. In addition to the open channel, another perforation, bag hole and / or milling section may be placed within the pump housing to accommodate the bent surface of the angle member. This preferably allows the use of more compact channels. For only the dimensions of the open channel need to be large enough to accommodate the connector of the connecting conductor in some cases, while the bent region of the channel is only the connecting conductor itself. This is because it is sufficient to accommodate the connector, and it is not necessary to accommodate the connector. The open channel also provides easy access to all edges formed within the channel during manufacturing so that the edges can be easily deburred and / or rounded. Thereby, it is possible to preferably avoid damage to the connecting conductor or the insulator of the connecting conductor.

Preferably, a seal element is arranged between the angle member and the pump housing. The seal element can be, for example , an O-ring or a seal strip. This allows the bent channel to be sealed even in the area of the separately mounted angle member, thus preventing the outflow of the encapsulant during injection, especially when the encapsulant is used as a gas barrier. The sealing element can be omitted when using different types of gas barriers or when using high viscosity encapsulant materials.

The spatial volume remaining between the gas barrier and the board in the vacuum region, for example at least in general, cannot be connected to both the pumping region and the pressure chamber of the vacuum chamber to guide the gas, and therefore: Also called dead space. Accordingly, the pressure difference between the dead space and the pumping region of the vacuum chamber separated by the gas barrier and adjacent to it, and / or the dead space, separated by the board and adjacent to it. The pressure difference between the pressure chamber and the dead space does not result in a direct pressure adaptation between the dead space and the pumping area and / or pressure chamber of the vacuum chamber. In some cases, the pressure that progresses slowly due to the remaining leak gas flow, which can be identified based on the leak rate between the pumping area of the vacuum chamber and the dead space, or between the pressure chamber and the dead space. Fittings can be achieved, but in the case of low leakage rates, this pressure fitting can be done, for example , hours or months later.

According to one embodiment, the area of the vacuum pump defined by the gas barrier and the board is connected to a secondary gas source.

Preferably, the secondary gas source provides, for example , a sealing gas, a protective gas, an inert gas or an aerated gas, whereby a predetermined atmosphere without corrosive components is formed in the dead space. Will be done. Such a protective gas atmosphere can effectively prevent unwanted gas diffusion from the pumping region of the vacuum chamber 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 can be adapted to the pressure in the pumping area of the vacuum chamber, in which case, for example , a gas under higher pressure in the dead space will slowly vacuum. Can diffuse into the pumping area of the room. When the vacuum pump is subsequently switched off and the pumping area of the vacuum chamber is ventilated, for example , again the gas diffuses back from the pumping area of the vacuum chamber to the dead space, depending on the leakage rate of the gas barrier. Can be. When the gas diffusing into the dead space still contains trace amounts of corrosive process gas, the corrosive process gas can cause damage to the board as a vacuum feedthrough. The protective gas atmosphere produced by the secondary gas source can suitably prevent such a situation.

Without a gas barrier, a large amount of protective gas must be flowed along the cable connection towards the pumping area of the vacuum chamber during and after operation of the vacuum pump to ensure adequate protection of the board. It doesn't become. Combined with at least a nearly airtight gas barrier, the increase in protective gas consumption to create a given atmosphere in the dead space is extremely small and negligible.

The secondary gas source can be connected to the dead space in various forms, eg , a perforation or cover of the secondary gas source towards another gas inlet already present in the vacuum pump. Separate dead space to the secondary gas source by the lateral connection in the form of a channel and / or by the transverse connection towards another region ventilated by the secondary gas source. Can be connected by the connection part of.

Another object of the present invention is a method for manufacturing a vacuum pump. In this manufacturing method, a vacuum chamber and a board defined by a pump housing are prepared, a connection opening is formed in the pump housing, and the connection opening is vacuum-tightly closed by the board, whereby the board presses the vacuum chamber. A gas barrier is formed in front of the board on the vacuum side that separates from the chamber and keeps the vacuum chamber or part of the vacuum chamber airtight so that corrosive gas does not come into contact with the board, and the gas barrier is separated from the board. It is assumed that it is. The vacuum pumps so manufactured can reasonably achieve the advantages mentioned above.

According to one embodiment, a channel with a bent or curved region may be formed within the pump housing, at least one connecting conductor may be laid through the channel, and a gas barrier may be formed in the bent or curved region of the channel. Can be formed, connecting conductors can be connected to the board, and the board can be vacuum tightly attached to the pump housing.

In this case, the channel can be formed in one piece by the pump housing or in multiple pieces by the pump housing and / or additional components such as angle members, covering elements or the like.

The order of the method steps can be changed depending on the specific configuration of the channel and other components. When an open channel with an angle member is used, for example , a connecting conductor can first be laid through the open channel before the bent channel is formed by assembling the angle member. The same is true for alternative or additional method steps.

Hereinafter, the present invention will be described, exemplary by way of example, with reference to the accompanying figures. A number of features are combined and disclosed in the drawings, the description of the drawings and the claims. Those skilled in the art would preferably consider these features individually and integrate them into another meaningful combination.

The perspective view of the turbo molecular pump is shown. The bottom view of the turbo molecular pump of FIG. 1 is shown. The cross-sectional view of the turbo molecular pump along the cutting line AA shown in FIG. 2 is shown. The cross-sectional view of the turbo molecular pump along the cutting line BB shown in FIG. 2 is shown. The cross-sectional view of the turbo molecular pump along the cutting line CC shown in FIG. 2 is shown. FIG. 6 shows a cross-sectional view of a lower portion of a pump having a bent channel, a gas barrier and a board as a vacuum feedthrough according to a first embodiment. The manufacturing schematic diagram for forming the channel of FIG. 6 is shown. FIG. 6 shows a cross-sectional view of the bent channel of FIG. FIG. 6 shows a cross-sectional view of the lower portion of the pump of FIG. 6 in the injection direction. FIG. 2 shows a cross-sectional view of a lower portion of a pump having a bent channel, a gas barrier and a board as a vacuum feedthrough according to a second embodiment. FIG. 8 shows a schematic manufacturing diagram for forming the channel of FIG. FIG. 8 shows a cross-sectional view of the bent channel of FIG. FIG. 8 shows a cross-sectional view of the lower portion of the pump in FIG. 8 in the injection direction. FIG. 3 shows a cross-sectional view of a lower portion of a pump having a bent channel with angle members, a gas barrier and a board as a vacuum feedthrough, according to a third embodiment. The plan view of the lower part of the pump and the angle member of FIG. 10 are shown. FIG. 10 shows a schematic manufacturing diagram for forming the open channel of FIG. FIG. 10 shows a cross-sectional view of a bent channel to which the angle member of FIG. 10 is attached. FIG. 10 shows a cross-sectional view of the lower portion of the pump in FIG. 10 in the injection direction. FIG. 3 shows a cross-sectional view of a vacuum pump having a pump lower portion according to a third embodiment.

The turbo molecular pump 111 shown in FIG. 1 has a pump inlet 115 surrounded by an inlet flange 113. A vacuum container (not shown) can be connected to the pump inlet 115 by a means known per se. Gas arriving from the vacuum vessel is drawn from the vacuum vessel through the pump inlet 115 and pumped through the pump to the pump outlet 117. A pre-vacuum pump ( eg , a rotary vane pump) may be connected to the pump outlet 117.

The inlet flange 113 forms the upper end of the housing 119 of the vacuum pump 111 in the direction of the vacuum pump of FIG. The pump housing 119 has a lower portion 121. An electronics housing 123 is arranged laterally in the lower portion 121. An electrical and / or electronic component of the vacuum pump 111 is housed within the electronics housing 123. These components are for operating, for example , an electric motor 125 arranged in a vacuum pump. The electronics housing 123 is provided with a plurality of connections 127 to accessories. Further, a data interface 129 ( for example , one conforming to RS485 standard) and a current supply connection unit 131 are arranged in the electronics housing 123.

The housing 119 of the turbo molecular pump 111 is provided with a ventilation inlet 133, particularly in the form of a ventilation valve. The vacuum pump 111 can be ventilated through the ventilation inlet 133. A seal gas connection portion 135 (also referred to as a purge gas connection portion) is further arranged in the region of the lower portion 121 of the pump. Through the seal gas connection portion 135, purge gas can be sent into the motor chamber 137 in order to protect the electric motor 125 (see, for example , FIG. 3) against the gas pumped by the pump. In the motor chamber 137, the electric motor 125 is housed in the vacuum pump 111. Two more coolant connecting portions 139 are arranged on the lower portion 121 of the pump. In this case, one coolant connection is provided as an inlet for the coolant and the other coolant connection is provided as an outlet. The coolant can be introduced into the vacuum pump for cooling purposes.

Since the lower surface 141 of the vacuum pump can be used as a base, the vacuum pump 111 can be operated vertically on the lower surface 141. However, the vacuum pump 111 can also be fixed to the vacuum container via the inlet flange 113, so that it can operate in a suspended state, so to speak. Further, the vacuum pump 111 may be configured to operate even when oriented in a manner different from that shown in FIG. It is also possible to realize a form of a vacuum pump in which the lower surface 141 can be arranged sideways or upward instead of downward.

Further, various screws 143 are arranged on the lower surface 141 shown in FIG. 2. These screws secure the components of the vacuum pump, which are not specified here in detail, to each other. For example , the bearing cover 145 is fixed to the lower surface 141.

A fixing hole 147 is further arranged on the lower surface 141. The pump 111 can be fixed , for example , to the installation surface via the fixing hole 147.

2 to 5 show the coolant pipe 148. In the coolant pipe 148, the coolant introduced or derived via the coolant connecting portion 139 can be circulated.

As shown in the cross-sectional views of FIGS. 3-5, the vacuum pump has a plurality of process gas pump stages. These process gas pump stages are for pumping the process gas acting on the pump inlet 115 to the pump outlet 117.

A rotor 149 is arranged in the pump housing 119. The rotor 149 has a rotor shaft 153 that can rotate about the rotation axis 151.

The turbo molecular pump 111 has a plurality of turbo molecular pump stages connected in series with each other so as to exert a pumping action. These turbo molecular pump stages have a plurality of radial rotor disks 155 fixed to the rotor shaft 153 and a stator disk 157 disposed between the rotor disks 155 and fixed within the housing 119. In this case, one rotor disk 155 and one stator disk 157 adjacent to the rotor disk 155 each form one turbo molecular pump stage. The stator discs 157 are held by spacer rings 159 at desired axial spacing from each other.

The vacuum pumps also have Holbeck pump stages that are radially located inside and outside of each other and connected in series with each other to exert a pumping action. The rotor of the Holbeck pump stage has a rotor hub 161 located on the rotor shaft 153 and two cylindrical flank rotor sleeves 163,165 fixed to the rotor hub 161 and supported by the rotor hub 161. These Holbeck rotor sleeves 163 and 165 are coaxially oriented with respect to the axis of rotation 151 and are connected in and out of each other in the radial direction. Further, two Holbeck stator sleeves 167 and 169 having a cylindrical side surface are provided. These Holbeck stator sleeves 167,169 are also coaxially oriented with respect to the axis of rotation 151 and are connected in and out of each other when viewed in the radial direction.

The pumping surface of the Holbeck pump stage is formed by the sides, i.e., the radial inner and / or outer surfaces of the Holbeck rotor sleeves 163,165 and the Holbeck stator sleeves 167,169. There is. The radial inner surface of the outer Holbeck stator sleeve 167 faces the radial outer surface of the outer Holbeck rotor sleeve 163, forming a radial Holbeck gap 171 and this Holbeck gap 171. At the same time, a first Holbeck pump stage following the turbo molecular pump is formed. The radial inner surface of the outer Holbeck rotor sleeve 163 faces the radial outer surface of the inner Holbeck stator sleeve 169, forming a radial Holbeck gap 173, and this Holbeck gap 173. At the same time, a second Holbeck pump stage is formed. The radial inner surface of the inner Holbeck stator sleeve 169 faces the radial outer surface of the inner Holbeck rotor sleeve 165, forming a radial Holbeck gap 175, and this Holbeck gap 175. At the same time, a third Holbeck pump stage is formed.

The lower end of the Holbeck rotor sleeve 163 may be provided with a channel extending radially. Through this channel, the Holbeck gap 171 located on the outer side in the radial direction is connected to the central Holbeck gap 173. Further, the upper end of the inner Holbeck stator sleeve 169 may be provided with a channel extending in the radial direction. Through this channel, the central Holbeck gap 173 is connected to the Holbeck gap 175 located inward in the radial direction. As a result, a plurality of Holbeck pump stages connected to each other inside and outside are connected in series with each other. The lower end of the Holbeck rotor sleeve 165 located radially inward may further be provided with a connecting channel 179 leading to the outlet 117.

Each of the above-mentioned pumping surfaces of the Holbeck stator sleeves 163 and 165 has a plurality of Holbeck grooves spirally orbiting around the rotation axis 151 and extending axially. On the other hand, the opposite sides of the Holbeck rotor sleeves 163,165 are smoothly formed and pump gas forward in the Holbeck groove for the operation of the vacuum pump 111.

A rolling bearing 181 is provided in the region of the pump outlet 117 and a permanent magnetic magnetic bearing 183 is provided in the region of the pump inlet 115 for the rotatable shaft support of the rotor shaft 153.

In the region of the rolling bearing 181 the rotor shaft 153 is provided with a conical splash nut 185. It has an outer diameter that increases towards the rolling bearing 181. The splash nut 185 is in sliding contact with at least one scraping member of the working medium reservoir. The working medium reservoir has a plurality of absorbent discs 187 stacked one above the other. These discs 187 are impregnated with a working medium for rolling bearings 181 such as a lubricant.

During operation of the vacuum pump 111, the working medium is transmitted from the working medium reservoir through the scraping member to the rotating splash nut 185 by capillary phenomenon and along the splash nut 185 based on centrifugal force. , Splash nut 185 is pumped towards the rolling bearing 181 towards the increasing outer diameter. There, for example , the lubrication function is exhibited. The rolling bearing 181 and the working medium storage portion are surrounded by a tank-shaped insert 189 and a bearing cover 145 in a vacuum pump.

The permanent magnet type magnetic bearing 183 has a bearing half portion 191 on the rotor side and a bearing half portion 193 on the stator side. They each have one ring stack, which consists of a plurality of rings 195,197 of permanent magnets stacked up and down in the axial direction. The ring magnets 195 and 197 face each other while forming a radial bearing gap 199, in which case the ring magnet 195 on the rotor side is radially outward and the ring magnet 197 on the stator side is radial. It is located inside the direction. The magnetic field present in the bearing gap 199 causes a magnetic repulsive force between the ring magnets 195 and 197. The repulsive force provides radial support for the rotor shaft 153. The ring magnet 195 on the rotor side is supported by the support portion 201 of the rotor shaft 153. The support portion 201 surrounds the ring magnet 195 on the outer side in the radial direction. The ring magnet 197 on the stator side is supported by the support portion 203 on the stator side. The support portion 203 extends through a ring magnet 197 and is suspended on a radial support 205 of the housing 119. The ring magnet 195 on the rotor side is fixed by the cover element 207 connected to the support portion 203 in parallel with the rotation axis 151. The ring magnet 197 on the stator side is fixed in one direction parallel to the rotation axis 151 by a fixing ring 209 coupled to the support portion 203 and a fixing ring 211 coupled to the support portion 203. Further, a disc spring 213 may be provided between the fixing ring 211 and the ring magnet 197.

An emergency bearing or a safety bearing 215 is provided in the magnetic bearing. The emergency bearing or safety bearing 215 slips in a non-contact manner during normal operation of the vacuum pump and only engages when the rotor 149 is excessively displaced in the radial direction relative to the stator. Since the collision between the structure on the rotor side and the structure on the stator side is prevented, a stopper in the radial direction with respect to the rotor 149 is formed. The safety bearing 215 is configured as a non-lubricated rolling bearing and forms a radial gap with the rotor 149 and / or the stator. This gap prevents the safety bearing 215 from engaging during normal pump operation. The radial displacement to which the safety bearing engages is sized sufficiently large that the safety bearing 215 does not engage during normal operation of the vacuum pump and is at the same time small enough so that the structure on the rotor side. Collision between the and the structure on the stator side is prevented in all situations.

The vacuum pump 111 has an electric motor 125 that rotationally drives the rotor 149. The armature of the electric motor 125 is formed by a rotor 149. The rotor shaft 153 of the rotor 149 extends through the motor stator 217. Permanent magnet assemblies may be placed in portions of the rotor shaft 153 extending through the motor stator 217, either radially outward or embedded. An intermediate chamber 219 is arranged between the motor stator 217 and the portion of the rotor 149 extending through the motor stator 217. The hollow chamber 219 has a motor gap in the radial direction. Through this motor gap, the motor stator 217 and the permanent magnet assembly transmit driving torque, so that they can magnetically influence each other.

The motor stator 217 is fixed in the motor chamber 137 provided for the electric motor 125 in the pump housing. Through the seal gas connection portion 135, the seal gas (also referred to as purge gas, which may be air or nitrogen, for example ) can reach the inside of the motor chamber 137. Through the seal gas, the electric motor 125 can be protected against a process gas, eg , a corrosive portion of the process gas. The motor chamber 137 can be evacuated via the pump outlet 117. That is, the vacuum pressure realized by the pre-vacuum pump connected to the pump outlet 117 acts at least approximately substantially on the motor chamber 137.

A so-called labyrinth seal 223 known per se may be further provided between the rotor hub 161 and the wall portion 221 defining the motor chamber 137. This achieves better sealing of the motor chamber 217, in particular for the Holbeck pump stage located radially outward.

FIG. 6 shows a first embodiment of the pump lower portion 121 of the turbo molecular pump 111 in an assembled operating state. The turbo molecular pump 111 has a vacuum chamber V defined by a pump housing 119, which is separated from the pressure chamber D by a board 241 as a feedthrough. The board 241 is vacuum-tightly attached to the pump housing 119 using an O-ring 243 in the area of the connection opening 225.

The vacuum chamber V has a bent channel 224, in which a gas barrier 231 is arranged, the gas barrier 231 is provided in front of the board 241 on the vacuum side, and the process gas is applied to the board. Isolate from the connection joints of 241 and board 241. In the illustrated embodiment, the gas barrier 231 is a sealing material that airtightly fills the siphon-bent region 229 (FIG. 7B) of the channel 224.

The board 241 is connected to the connecting conductor 233 , which extends through the gas barrier 231 to the opening 239 towards the pumping region 240 (FIG. 8) of the turbomolecular pump 111. The connecting conductor 233 has a connector 235, and the connector 235 is connected to the board 241. The connector 235 and the portion of the connecting conductor 233 that connects to the connector 235 are housed in the accommodation chamber 226 of the bent channel 224. The connecting conductor 233 may be connected to the motor, actuator system and / or sensor system of the turbomolecular pump 111 at its end near the pumping region 240.

Since the encapsulant material 231 is not in contact with the board 241 or the connector 235, contact failure due to the gas barrier 231, particularly due to the encapsulant material, cannot occur. Thus, the gas barrier 231 and the board 241 define a region of the vacuum chamber V, referred to as the dead space T, which is at least substantially substantially the pumping region 240 and the pressure to guide the gas. Not connected to room D. A secondary gas source (not shown) can be connected to the dead space T, which allows the protective gas to ventilate the dead space T, thereby corroding. Sexual process gas is more effectively isolated from the board 241. The pump lower portion 121 may be oriented as needed in the operating state or may be arranged in any orientation as needed. This is because the cured encapsulation material 231 retains its action as a gas barrier under all orientations.

The encapsulating material 231 is located exclusively in the pump lower portion 121 and is not in contact with the pump upper portion 249 (FIG. 8) defining the pumping region 240 of the vacuum chamber in the illustrated embodiment. Therefore, the pump lower portion 121 can be easily disassembled and handled separately, preferably for service, maintenance and repair purposes. Additional flexibility during assembly and disassembly of the turbomolecular pump 111 is obtained by the pluggable configuration of the connection joints of the board 241 which allows easy replacement of, for example , the board 241. It becomes.

7A-7C illustrate the manufacture of the first embodiment of the pump lower portion 121 in FIG. For clarity, other components of the turbomolecular pump 111, located within the pump lower portion 121, are not shown.

In FIG. 7A, a portion of the channel 224 provided for accommodating the gas barrier 231 is made up of two bag holes 227a, 227b that intersect each other, with the bag holes 227a, 227b of the pump lower portion 121, each other. Starting from the opposite side, the illustrated embodiment shows crossing at an angle of 90 °. Of course, different angles can be considered in principle, depending on the structural peripheral conditions. The first bladder hole 227a starts from the side of the predetermined pressure chamber D in the pump housing 119 and defines the connection opening 225. The second bag hole 227b defines an opening 239 towards the pumping region 240 of the turbomolecular pump 111. The pump housing 119 has a third bag hole 227c in the area of the connection opening 225, where the third bag hole 227c accommodates the channel 224 for accommodating electrical or electronic connection components. Expand by the amount of room 226. In the illustrated embodiment, the third bag hole 227 and the first bag hole 227a intersect at an angle of 45 °, in which case another angle is possible here as well.

FIG. 7B shows the entire cross section of the resulting channel 224. In the region where the first bag hole 227a and the second bag hole 227b intersect, the channel 224 has a region having a curved contour 229, which contour 229 is in the illustrated orientation of the pump lower portion 121. , Oriented to the right.

FIG. 7C shows the pump lower portion 121 during the introduction of the gas barrier 231 in the injection direction corresponding to the state in which the pump lower portion 121 is rotated 90 ° to the right with respect to the operating state in FIG. 6 in the illustrated embodiment. Shows. Through the channel 224, the connecting conductor 233 is first laid, and the connecting conductor 233 has a connector 235 for connecting to the board 241 on the side of the connecting opening 225. In this case, the dimensions of the channel 224 are selected so that the connecting conductor 233 and the connector 235 can be conducted. A seal groove 237 is provided to accommodate an O-ring 243 for vacuum-tightly assembling the board 241.

In the illustrated embodiment, the gas barrier 231 is configured as a sealing material, which initially has sufficient fluidity to be introduced into channel 224 by injection, followed by It cures there. For injection, the pump lower portion 121 is positioned such that the bent region 229 forms the lowest point of the channel 224 in the form of a siphon, as shown. Through the connection opening 225 and / or the opening 239 towards the pump region 240, the encapsulant material 231 is introduced into the siphon-like region 229 of the channel 224 until the channel 224 is airtightly closed. At that time, the connecting conductor 233 is embedded in the sealing material 231. The area before and after the encapsulant remains open from the gas barrier 231 so that the encapsulant does not contact the connection joints of the board 241 or board 241. The pump lower portion 121 is held in the illustrated orientation until the encapsulation material 231 cures.

FIG. 8 shows a second embodiment of the pump lower portion 121 of the turbo molecular pump 111 in an assembled operating state, and FIGS. 9A-9C schematically show the manufacture of the second embodiment. .. The second embodiment is largely similar to the first embodiment shown in FIG. 6, and therefore, the differences between these embodiments are specifically referred to below.

FIG. 8 shows a pump lower portion 121, which has a board 241 as a vacuum feedthrough and a bent channel 224, in which a gas barrier 231 is arranged. Another pump portion, here the pump upper portion 249 defining the pumping region 240 of the turbomolecular pump 111, is assembled on the pump lower portion 121 and is sealed by an O-ring located in the seal groove 247. ing.

As shown in FIG. 9A, the channel 224 is made up of two bag holes 227a, 227b, the bag holes 227a, 227b intersect at an angle of 90 °, in this case structural. Considering the circumstances, another angle can be selected . Since both bag holes 227a and 227b are formed from the same side of the pump lower portion 121, here the side of the pumping region 240, perforations are provided in the opening 239 towards the pumping region 240 and in the pump housing 119. It defines another perforated opening 251. A milling section 245 provided on the opposite side of the pump lower portion 121 completes the conduction of the bent channel 224 to the side of the connection opening 225. Compared to the channel 224 of FIG. 6, the connection opening 225 for the board 241 as a vacuum feedthrough can be configured smaller here. This is because the milling section 245 forms a right angle to the surface of the pump housing 119.

FIG. 9B shows the entire cross section of the resulting channel 224. The intersecting bag holes 227a, 227b form a siphon-like bent region 229 of the channel 224.

FIG. 9C shows the lower portion 121 of the pump in the orientation during introduction of the encapsulation material as the gas barrier 231 in the injection direction. Since both blind holes 227a, 227b in FIG. 9A are formed from the same side of the pump housing 119, the pump upper portion 249 is already assembled at the time of injection to seal the perforation opening 251 with the sealing material 231. Must be. The opening 239 establishes communication between the channel 224 and the pumping region 240 of the turbomolecular pump 111.

In order to inject and mold the gas barrier 231 into the channel 224, the pump lower portion 121 and the pump upper portion 249, together with the conductive connecting conductor 233, fill the siphon-shaped bent region 229 with the encapsulation material 231 from the connecting opening 225. It is arranged so that it can be done. At that time, the perforation opening 251 is similarly filled with the encapsulating material 231, and the perforation opening 251 is sealed by contact with the pump upper portion 249.

After the encapsulation material 231 has hardened, the board is vacuum chambered so that the board 241 can be connected to the connector 235 of the connecting conductor 233 and vacuum tightly assembled over the connection opening 225 of the pump lower portion 121. V is separated from the pressure chamber D. In this case, the pump lower member 121 and the pump upper portion 249 may be oriented as set for the operation of the turbomolecular pump 111, in particular the pump lower portion 121 downward and the pump upper portion 249. It may be oriented upwards (Fig. 8).

A third embodiment of the pump lower portion 121 is shown in cross section in FIG. 10, and steps for making this type of pump lower portion 121 are outlined in FIGS. 11A-11C. The illustrated embodiment has a labyrinth-like bent channel 224 multiple times. In this case, the bent region is partially defined by the surface of the pump housing 119 and partly by the angle member 259 fixed to the pump housing 119.

FIG. 11A shows the lower portion 121 of the pump in plan view from the side of the pumping region 240 of the turbomolecular pump 111, and shows the angle member 259 before assembly. An open channel 253 is perforated through the pump lower portion 121, and the pump lower portion 121 is adjacent to the open channel 253 and additionally has a first recess 255a and a second recess for accommodating the connecting conductor 233. Has a recess of 255b. A fixed region 260 is provided for assembling the angle member 259 to the lower portion 121 of the pump. Since the seal groove 257 surrounds the open channel 253 and the recesses 255a, 255b, the seal element 261 can be placed between the angle member 259 and the pump housing 119.

FIG. 11B shows a cross-sectional view of a pump lower portion 121 having an open channel 253 and recesses 255a, 255b. Due to the open structural morphology, all edges 262 are well accessible for machining. In particular, the edge 262 can be deburred or rounded so that the insulator of the connecting conductor 233 or the connecting conductor 233 is not damaged.

As shown in FIG. 11C, the open channel 253, the recesses 255a, 255b, and the assembled angle member 259 form a labyrinth-like channel 224, and the wall portion of the channel 224 is the pump housing 119. And the angle member 259 attached to the pump housing 119. The channel 224 has a bent region 229, the region 229 being provided to accommodate a gas barrier 231 such as a sealing material. Compared to the first and second embodiments of channel 224 shown in FIG. 6 or FIG. 8, the openly configured channel 253 conducts the connector 235 over its entire stretch length portion. It does not have to have the dimensions that allow it. Rather, the bent region 229 only needs to provide space for the connecting conductor 233, which allows for compact dimensions of the channel. A seal strip 261 guided in the seal groove 257 between the angle member 259 and the pump housing 119 seals the channel 224.

In order to inject and mold the encapsulating material as the gas barrier 231 the pump lower portion 121 conducts the connecting conductor 233 through the open channel 253 and after assembling the angle member 259 to form the labyrinth-like channel 224. Since it is positioned in the injection molding direction, injection into the bent region 229 can be performed from the connection opening 225 (FIG. 11D). The seal strip 261 seals region 229 when a lower viscosity encapsulation material is used, but can be omitted for higher viscosity encapsulation materials.

After the encapsulation material 231 has hardened, the connecting conductor 233 can be connected to the board 241 via the connector 235, the board 241 can be vacuum tightly assembled to the pump housing 119 over the connection opening 225, and the bottom of the pump. 121 can be oriented as set for the operation of the turbomolecular pump 111 and coupled to the pump top 249 of the pump.

To avoid gas exchange between the pumping region 240 of the turbomolecular pump 111 and the board 241 through the inner and / or outer surface of the insulator of the connecting conductor 233 through the encapsulating material 231. The connecting conductor 233 in 12 has at least a partially airtight covering 265 in the region of the gas barrier 231. In particular, in the end region of the gas barrier 231 which is in direct contact with the vacuum region V on the side of the pumping region 240 or the side of the board 241 the airtight covering 265 is the surface or insulator of the connecting conductor 233. It blocks the entry of gas into, and thus the possible passage of gas through the encapsulating material 231 along the connecting conductor 233. As shown here, the airtight covering 265 is obtained by a shrink tube, particularly a shrink tube containing an inner adhesive.

As shown in FIG. 12, at the end of the connecting conductor 233 on the side away from the board 241 in order to prevent gas exchange through the inside of the connecting conductor 233, the motor and actuator system of the turbo molecular pump 111. And / or the connection point 267 leading to the sensor system can also be embedded in the encapsulation material 269.

111 Turbo molecular pump 113 Inlet flange 115 Pump inlet 117 Pump outlet 119 Pump housing 121 Pump lower part 123 Electronics housing 125 Electric motor 127 Accessory connection 129 Data interface 131 Current supply connection 133 Ventilation inlet 135 Seal gas connection 137 Motor room 139 Coolant connection 141 Bottom bottom 143 Thread 145 Bearing cover 147 Fixing hole 148 Coolant piping 149 Rotor 151 Rotating axis 153 Rotor shaft 155 Rotor disk 157 Stator disk 159 Spacer ring 161 Rotor hub 163 Holbeck Rotor sleeve 165 Holbeck Stator sleeve 169 Holbeck stator sleeve 171 Holbeck gap 173 Holbeck gap 175 Holbeck gap 179 Connection channel 181 Rolling bearing 183 Permanent magnet type magnetic bearing 185 Splash nut 187 Disc 189 Insert 191 Rotor side bearing half 193 Bearing half 195 Ring magnet 197 Ring magnet 199 Bearing gap 201 Support part 203 Support part 205 Radial column 207 Cover element 209 Support ring 211 Fixing ring 213 Countersunk spring 215 Emergency bearing or safety bearing 217 Motor stator 219 Intermediate chamber 221 Wall part 223 Labyrinth Seal 224 Channel 225 Connection opening 226 Containment chamber 227a First bag hole 227b Second bag hole 227c Third bag hole 229 Siphon-bent area 231 Gas barrier 233 Connection conductor 235 Connector 237 Seal groove for board 239 Pumping area Facing opening 240 Pumping area 241 Board 243 O-ring 245 Milling part 247 Seal groove for pump upper part 249 Pump upper part 251 Perforated opening 253 Open channel 255a First recess 255b Second recess 257 Seal groove for angle member 259 Angle member 260 Fixed area 261 Seal strip 262 Edge 265 Airtight covering 267 Motor, actuator system, Connection point with sensor system 269 Sealing material for connection point V Vacuum chamber D Pressure chamber T Dead space

Claims (9)

The vacuum chamber (V) defined by the pump housing (119),
A vacuum pump with a board (241).
The pump housing (119) has a connection opening (225), which is vacuum tightly closed by the board (241), whereby the board (241) is vacuum chamber (V). From the pressure chamber (D)
A gas barrier (231) that keeps the vacuum chamber (V) or a part of the vacuum chamber (V) airtight and does not allow corrosive gas to come into contact with the board (241) is on the vacuum side in front of the board (241). It is provided apart from 241),
The gas barrier (231) is formed in the pump housing (119) and is located in the channel (224) communicating with the vacuum chamber (V).
The channel (224) has a bent or curved region (229), the region (229) being filled by a gas barrier (231).
The curved region (229) of the channel (224) is bent in a labyrinth-like manner.
The curved region (229) of the channel (224) is characterized by being defined by a surface of the pump housing (119) and an angle member (259) fixed to the pump housing (119).
Vacuum pump. The vacuum pump (111) according to claim 1, wherein the gas barrier (231) includes a sealing material. The vacuum pump (111) of claim 1 or 2, wherein at least one connecting conductor (233) extends through a gas barrier (231) and is connected to a board (241). The vacuum pump (111) according to claim 3, wherein the connection between the connecting conductor (233) and the board (241) is a plug-in connection. The connecting conductor (233) is characterized by having at least a nearly airtight covering (265) in the region of the gas barrier (231), at least partially or in the end region of the gas barrier (231). 3 or 4 the vacuum pump (111). The gas barrier (231) is arranged in the first pump portion (121) of the vacuum pump (111) and defines the pumping region (240) of the vacuum chamber (V) of the vacuum pump (111). The vacuum pump (111) according to any one of claims 1 to 5, characterized in that it is not in contact with the pump portion (249) of the above. Claimed, the bent region (229) of the channel (224) is formed by at least two intersecting perforations, bladder holes (227a, 227b, 227c) or milling portions (245). The vacuum pump (111) according to 1 . The vacuum pump (111) according to claim 1 , wherein a seal element (261) is arranged between the angle member (259) and the pump housing (119). Any of claims 1-8 , wherein the region of the vacuum chamber (V) defined by the gas barrier (231) and the board (241) is connected to a secondary gas source. The vacuum pump (111) according to item 1.

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