Turbo molecular vacuum pump

Abstract

To provide a turbo molecular vacuum pump that includes a stator, a rotor, and a stator blade and has an exhaust speed improved for respective states in a region of a pump intake port.SOLUTION: A stator blade 20 includes a fitting part 28 with an end part 30 for being fitted to a stator 12. The stator blade is fitted to the stator by the end part. The end part defines a fitting plane 32. A blade plane 26 and the fitting plane extend while being perpendicular to a rotation axis 18 and are separated from each other along the rotation axis.SELECTED DRAWING: Figure 9A

Description

Technical Field

[0001] The present invention relates to a turbomolecular vacuum pump including a stator, at least one rotor having a plurality of rotor blades circumferentially distributed, the rotor being rotatably drivable about a rotation axis to exert a pumping action, and at least one stator blade attached to the stator, interacting with the rotor to exert a pumping action and having a plurality of stator blades circumferentially distributed, the stator blades defining a blade plane.

Background Art

[0002] The blade plane is understood to be a plane extending perpendicular to the rotation axis in which the stator blades are located. That is, the blade plane may be defined by any part of the stator blade as long as it intersects or contacts the stator blade. Thus, the blade plane may extend through the stator blade centrally in the axial direction, for example, extending parallel to the rotation axis, or may be defined by the upper or lower blade edges.

[0003] A turbomolecular vacuum pump should have the highest possible exhaust speed, especially. In this context, the design of the intake region, especially the region near the pump intake defining the intake port plane, is extremely important. In this case, the optimal utilization of the structural space provided in the pump housing for accommodating the components that exert the pumping action, especially the rotor-stator set located closest to the pump intake, is particularly important. In this context, the rotor-stator set is understood to be a set of moving blades and stator blades arranged alternately axially one above the other.

[0004] Generally, the stationary blades are attached to the stator by clamping the radially outer region of the stationary blades. In this case, the clamping or sandwiching is specifically carried out in a plane axially located at the height of the blade plane by a spacer ring fitted in the pump housing. The spacer ring and the pump housing are components of the stator of the vacuum pump, that is, within the scope of the present disclosure, the pump housing is regarded as a component of the stator. In this case, the stationary blades are sandwiched between two spacer rings that are directly continuous axially. In the case of stationary blades made of metal plates, for example, the collar region that circumscribes the radially outer side of the stationary blades is axially clamped via the spacer ring. On the other hand, in the case of milled or sawn stationary blades, the blades may be axially clamped with their radially outer blade tips, that is, with their free end portions. To axially clamp the stationary blades to the stator, a radial structural space is required within the pump housing.

[0005] When designing the intake region of a turbomolecular vacuum pump, that is, the region of the components that exhibit the pumping action and that is located closest to the pump intake port, in order to obtain the highest possible exhaust speed, an attempt is made to arrange the rotor-stator set as close as possible axially to the pump intake port. That is, the first moving blade on the intake side should be located as close as possible axially to the pump intake port in order to minimize flow losses. At the same time, the rotor-stator set and thus also the first stationary blade already located there should have the largest possible outer diameter with respect to the inner diameter of the respective pump housing located there.

[0006] Here too, it must be noted that in the region of the pump intake port, the structural space is restricted by the pump flange and the means used to connect the pump flange to the recipient flange. These means may in particular be screws, in which case it must also be considered that sufficient space must be provided within the flange for handling the screws and for the tools for moving the screws. Moreover, the pump flange must meet certain standards, for example ISO standards, especially with regard to its diameter.

[0007] Since the above-mentioned peripheral conditions limit the structural space provided for the moving blades and the stationary blades in the region of the pump inlet, the rotor stator set cannot be arbitrarily arranged near the pump inlet when the outer diameter of the first stationary blade must be as large as possible at the same time. Summary of the Invention Problems to be Solved by the Invention

[0008] Therefore, an object of the present invention is to provide a turbo molecular vacuum pump having an improved exhaust speed with respect to each situation in the region of the pump inlet. Means for Solving the Problems

[0009] According to the present invention, this problem is solved by the turbo molecular vacuum pump according to claim 1, in particular, the stationary blade has a mounting portion having an end portion for mounting to the stator, and with the end portion, the stationary blade is mounted to the stator, the end portion defines a mounting plane, and the blade plane and the mounting plane extend perpendicular to the axis of rotation and are spaced apart from each other along the axis of rotation.

[0010] The end portion is a part of the mounting portion that directly interacts with the stator (for example, a spacer ring and a shoulder portion of the pump housing or two spacer rings) for mounting the stationary blade to the stator.

[0011] The mounting plane is a plane in which at least a part of the end portion that is further spaced from the blade plane than other regions of the mounting portion in the axial direction is located.

[0012] By having the mounting plane and the blade plane axially spaced apart from each other, the blade plane can be arranged closer to the pump inlet when the axial mounting positions are the same. Therefore, it is possible to reduce the flow loss in the inlet region and improve the exhaust speed. Based on the parameters of existing turbo molecular vacuum pumps, it has been found that an improvement in the exhaust speed of more than 3% can actually be achieved for the main gas, namely nitrogen. In one example, in the calculation, it was assumed that the rotor stator set located closest to the pump inlet was positioned 10 mm closer to the pump inlet than those without the configuration according to the present invention. For the gas nitrogen, an increase from 240 liters / second in the conventionally used configuration to 249 liters / second in the configuration according to the present invention was obtained.

[0013] The geometry of the inlet region, particularly the pump housing and the flange region, does not need to be modified for the present invention. Therefore, the pump according to the present invention meets the respective standards such as ISO standards here.

[0014] Advantageous embodiments of the present invention are described in the dependent claims, the specification and the drawings.

[0015] According to one embodiment, the blade plane is axially closer to the pump inlet than the mounting plane. Thereby, the structural state of the existing turbo molecular vacuum pump, particularly the shoulder portion of the pump housing present in or near the inlet region, can still be used for mounting the stationary blades, particularly the first stationary blades.

[0016] According to one embodiment, the stationary blades are integrally formed.

[0017] The stationary blades may be a punched and / or bent part made of a metal plate, i.e., a so-called metal plate stationary blade, or may be manufactured by machining the starting material. These possibilities for manufacturing the stationary blades are basically known and are suitable for the present invention as long as they enable the manufacture of stationary blades having axially spaced blade planes and mounting planes configured according to the present invention.

[0018] In fact, the stationary vanes of the metal plate often consist of two semi-circular or semi-annular halves in order to facilitate assembly or to enable assembly in the first place. Therefore, when referring to the "stationary vane" in this case, it means the two halves joined together. In short, in the present disclosure, when referring to an integral or one-piece configuration in relation to such stationary vanes of the metal plate, the two halves of the stationary vane are each understood to be integral.

[0019] In the stationary vane of the metal plate, the mounting portion may be formed by a collar on the outer radial side of the stationary vane. The collar has an end portion on the outer radial side and is coupled to the stator blade on the inner radial side. Therefore, while a known stationary vane of the metal plate is disk-shaped over its entire diameter, that is, including the collar on the outer radial side, the stationary vane according to the present invention has a mounting portion on the outer radial side, and the mounting portion leads from the blade plane to a mounting plane defined by its end portion.

[0020] In principle, specifically, depending on the respective configuration of the turbo molecular vacuum pump each time, it is also possible to configure the collar on the inner radial side of the stationary vane as the mounting portion, so that the stationary vane can be tightened to the stator on the inner radial side.

[0021] In this case, the mounting portion may have a collar portion on the outer radial side or the inner radial side. The collar portion is located within the blade plane and is coupled to the stationary vane.

[0022] According to another embodiment, the mounting portion is formed by the free end portion of the stator blade. In particular, a stationary vane that has been sawed or milled may be configured in this way. In this case, at least some, preferably all, of the stator blades have a radial, particularly outer radial, end portion leading from the blade plane to the mounting plane, and in this case, these end portions together form the mounting portion of the stationary vane.

[0023] According to one embodiment, the mounting portion has a transition portion that leads from the blade plane to the end portion of the mounting portion. The dimensions and / or shape of the transition portion can be basically arbitrarily selected, whereby, in particular, the axial spacing between the blade plane and the mounting plane can be adjusted. The transition portion is not directly attached to the stator, but rather the stator vanes are attached to the stator, for example by clamping, via the end portion.

[0024] According to one embodiment, the transition portion has at least partially the shape of a cylinder or a cone having a rotation axis as a central axis.

[0025] According to one embodiment, the end portion of the mounting portion has an annular shape or a conical shape having a rotation axis as a central axis, or has a curved path within a cross section including the rotation axis. The shape of the end portion can be basically arbitrarily selected, in particular according to the clamping form desired each time in the stator.

[0026] According to one embodiment, the mounting portion has or includes an L-shape in a cross section including the rotation axis. That is, illustratively speaking, the stator vane may be configured in a pot or hat shape.

[0027] According to one embodiment, the L-shape is formed by the transition portion and the end portion of the mounting portion. In this case, the transition portion extends parallel to the rotation axis, while the end portion extends perpendicular to the rotation axis and thus extends within the mounting plane, that is, the end portion defining the mounting plane is completely located within the mounting plane.

[0028] According to one embodiment, the stationary blade is part of a turbo molecular pump stage comprising a plurality of stationary blades and a plurality of moving blades of a rotor, each having a plurality of rotor blades, and the stationary blade and the moving blade interact to exert a pumping action. The turbo molecular pump stage may have one or more rotor stator sets. The stationary blade is in particular part of the first rotor stator set, i.e., the one closest to the pump intake. In particular, the first stationary blade of the rotor stator set, i.e., the one closest to the pump intake, is configured in accordance with the present invention.

[0029] According to one embodiment, the stationary blade is the stationary blade among a plurality of stationary blades spaced apart from each other in the axial direction of the stator and closest in the axial direction to the pump intake. Additionally or alternatively, in addition to this stationary blade, one or more stationary blades having the same structure as the stationary blade may be provided, and in the one or more stationary blades, the blade plane is located closer to the pump intake than the mounting plane in the axial direction. In this case, the axial distance between the blade plane and the mounting plane may be the same for all stationary blades configured in accordance with the present invention, or may vary, for example, increase or decrease towards the pump intake. By stationary blades of the same configuration are meant in this case stationary blades in which the blade plane and the mounting plane are spaced apart from each other in the axial direction, i.e., along the axis of rotation. Stationary blades of the same structure in this sense may be the same, but this is not essential, and the stationary blades may differ from each other in other respects. For example, stationary blades of the same configuration may have different diameters. The axial distance between the blade plane and the mounting plane may also differ for stationary blades of the same configuration.

[0030] According to one embodiment, the stationary blade is axially clamped between the stator by means of an end portion of the mounting part. Such a possibility of mounting the stationary blade to the stator is basically known and thus conforms to the present invention, i.e., the present invention does not necessarily require a novel mounting method.

[0031] According to one embodiment, exactly one stator vane is sandwiched between two spacer rings each configured as a separate component. Alternatively, two or more stator vanes may be sandwiched between the same two spacer rings. Only one, a plurality, or all of the two or more stator vanes may be configured according to the present invention, i.e., may have a spacing between the blade plane and the mounting plane.

[0032] According to one embodiment, exactly one stator vane is sandwiched between a spacer ring configured as a separate component and the shoulder portion of the stator, in particular the shoulder portion of the pump housing forming part of the stator. Alternatively, two or more stator vanes may be sandwiched between the spacer ring and the shoulder portion. Only one, a plurality, or all of the two or more stator vanes may be configured according to the present invention, i.e., may have a spacing between the blade plane and the mounting plane. Thus, the present invention is also suitable for these generally known mounting methods.

[0033] According to one embodiment, the stator, in particular the pump housing forming part of the stator, has in the region of the pump intake a flange portion for establishing a mechanical connection with the recipient and a shoulder portion axially spaced from the pump intake, the shoulder portion defining, together with the flange portion, an assembly region 44 for at least one coupling element, in particular at least one screw, to be mounted on the flange portion, and exactly one stator vane is sandwiched between a spacer ring configured as a separate component and the shoulder portion, or two or more stator vanes are sandwiched between the spacer ring and the shoulder portion. Here too, only one, a plurality, or all of the two or more stator vanes may be configured according to the present invention, i.e., may have a spacing between the blade plane and the mounting plane.

[0034] Such a configuration of the intake port region of the turbo molecular vacuum pump, that is, a configuration having a shoulder portion axially spaced from the flange portion, is basically known, and according to what it means, the present invention is also suitable for this kind of configuration. Therefore, the stator vane according to the present invention may be configured to be fastened particularly to the shoulder portion of the stator, especially the pump housing.

[0035] According to a preferred development form, the stator vane sandwiched between the spacer ring and the shoulder portion is the stator vane located closest axially to the pump intake port. The mounting plane of this stator vane is located in the region of the shoulder portion, and the blade plane of this stator vane is located between the pump intake port and the shoulder portion.

[0036] According to the present invention, further according to independent claim 15, it relates to a stator vane for a turbo molecular vacuum pump. The stator vane is a plurality of stator blades arranged dispersedly in the circumferential direction, the stator blades defining a blade plane, and a mounting portion having an end portion. With the end portion, the stator vane can be mounted to the stator of the turbo molecular vacuum pump. The end portion includes a mounting portion defining a mounting plane. The stator vane defines a central axis, and the blade plane and the mounting plane extend perpendicular to the central axis and are spaced apart from each other along the central axis. When the stator vane is used as specified in the turbo molecular vacuum pump according to the present invention, the central axis of the stator vane coincides with the rotation axis of the rotor.

[0037] The stator vane may be configured like the stator vane of the turbo molecular vacuum pump according to the present invention described above. That is, the development form of the stator vane disclosed in relation to the turbo molecular vacuum pump is also applicable to the stator vane claimed in independent claim 15.

[0038] Hereinafter, the present invention will be described exemplarily with reference to the drawings.

Brief Description of the Drawings

[0039]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 7

Figure 8

Figure 9A

Figure 9B

Figure 9C

Figure 10A

Figure 10B

Figure 10C

Figure 10D

Figure 10E

Mode for Carrying Out the Invention

[0040] The prior art turbo molecular pump 111 shown in FIG. 1 has a pump intake 115 surrounded by an intake flange 113. As is known per se, a recipient (not shown) may be connected to the pump intake 115. The gas arriving from the recipient is sucked in from the recipient through the pump intake 115 and can be pumped through the pump to the pump exhaust 117. An auxiliary vacuum pump, such as a rotary vane pump, for example, may be connected to the pump exhaust 117.

[0041] In the orientation of the vacuum pump according to FIG. 1, the intake flange 113 forms the upper end of the housing 119 of the vacuum pump 111. The housing 119 has a lower part 121. A lateral electronics housing 123 is arranged in the lower part 121. The electronics housing 123 houses the electrical and / or electronic components of the vacuum pump 111 for operating, for example, an electric motor 125 (see also FIG. 3) arranged within the vacuum pump. The electronics housing 123 is provided with a plurality of connections 127 for accessories. Furthermore, a data interface 129 (for example, compliant with the RS485 standard) and a current supply connection 131 are arranged in the electronics housing 123.

[0042] There are also turbo molecular pumps that are connected to external drive electronics without having this type of attached electronics housing.

[0043] In the housing 119 of the turbo molecular pump 111, an intake port 133 for ventilation is provided, particularly in the form of a ventilation valve. The vacuum pump 111 can be ventilated through the intake port 133 for ventilation. In the region of the lower part 121, further above it, a seal gas connection part 135 (also referred to as a purge gas connection part) is arranged. Through the seal gas connection part 135, purge gas can be fed 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 accommodated in the vacuum pump 111. In the lower part 121, further above it, two coolant connection parts 139 are arranged. In this case, one coolant connection part is provided as an intake port for the coolant, and the other coolant connection part is provided as an exhaust port. The coolant can be introduced into the vacuum pump for cooling purposes. Another turbo molecular vacuum pump (not shown) that exists is operated exclusively in an air-cooled manner.

[0044] Since the lower surface 141 of the vacuum pump can be used as a base, the vacuum pump 111 can be operated vertically with reference to the lower surface 141. Moreover, the vacuum pump 111 can be fixed to the recipient via the intake flange 113 and thus can be operated in a so-called suspended state. Furthermore, the vacuum pump 111 can be configured to be operable even when it is oriented in a direction different from that shown in FIG. 1. It is also possible to realize a form of the vacuum pump in which the lower surface 141 is not arranged downward but horizontally or upward. In this case, in principle, any angle is conceivable.

[0045] Another turbo molecular vacuum pump (not shown) that exists and is larger than the particularly shown pump cannot be operated vertically.

[0046] In the lower surface 141 shown in FIG. 2, various screws 143 are further arranged. By these screws 143, the components of the vacuum pump, which are not specified in detail here, are fixed to each other. For example, the bearing cover 145 is fixed to the lower surface 141.

[0047] At 141 below, fixing holes 147 are further arranged. Through the fixing holes 147, the pump 111 can be fixed to, for example, the installation surface. This is impossible for another existing turbo molecular vacuum pump (not shown) that is larger than the specifically illustrated pump.

[0048] From FIG. 2 to FIG. 5, a coolant pipeline 148 is shown. Inside the coolant pipeline 148, the coolant introduced and discharged through the coolant connection part 139 can circulate.

[0049] As shown in the cross-sectional views from FIG. 3 to FIG. 5, the vacuum pump has a plurality of process gas pump stages. The process gas pump stages are for pumping the process gas acting on the pump intake port 115 to the pump exhaust port 117.

[0050] Inside the housing 119, a rotor 149 is arranged. The rotor 149 has a rotor shaft 153 that is rotatable about the rotation axis 151.

[0051] 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. The turbo molecular pump stages have a plurality of radial moving blades 155 fixed to the rotor shaft 153, and a plurality of stationary blades 157 arranged between the moving blades 155 and fixed inside the housing 119. In this case, one moving blade 155 and one adjacent stationary blade 157 form one turbo molecular pump stage. The stationary blades 157 are held at a desired axial interval from each other by a spacer ring 159.

[0052] The vacuum pump further has Holweck pump stages arranged inside and outside each other in the radial direction and connected in series with each other so as to exert a pumping action. There is another turbo molecular vacuum pump (not shown) that does not have Holweck pump stages.

[0053] The rotor of the Holweck pump stage has a rotor hub 161 arranged on the rotor shaft 153, and two cylindrical side surface-shaped Holweck rotor sleeves 163, 165 fixed to the rotor hub 161 and supported by this rotor hub 161. The Holweck rotor sleeves 163, 165 are oriented coaxially with respect to the rotation axis 151 and are engaged with each other inside and outside in the radial direction. Two cylindrical side surface-shaped Holweck stator sleeves 167, 169 are further provided. The Holweck stator sleeves 167, 169 are similarly oriented coaxially with respect to the rotation axis 151 and are engaged with each other inside and outside in the radial direction when viewed in the radial direction.

[0054] The pumping surface of the Holweck pump stage is formed by the side surfaces, that is, the inner and / or outer side surfaces in the radial direction of the Holweck rotor sleeves 163, 165 and the Holweck stator sleeves 167, 169. The inner side surface in the radial direction of the outer Holweck stator sleeve 167 faces the outer side surface in the radial direction of the outer Holweck rotor sleeve 163 while forming a radial Holweck gap 171, and together with this outer side surface, forms the first Holweck pump stage following the turbo molecular pump. The inner side surface in the radial direction of the outer Holweck rotor sleeve 163 faces the outer side surface in the radial direction of the inner Holweck stator sleeve 169 while forming a radial Holweck gap 173, and together with this outer side surface, forms the second Holweck pump stage. The inner side surface in the radial direction of the inner Holweck stator sleeve 169 faces the outer side surface in the radial direction of the inner Holweck rotor sleeve 165 while forming a radial Holweck gap 175, and together with this outer side surface, forms the third Holweck pump stage.

[0055] A radially extending channel may be provided at the lower end of the Holbeck lotus sleeve 163. Through the channel, the Holbeck gap 171 located radially outside is connected to the central Holbeck gap 173. A radially extending channel may further be provided at the upper end of the inner Holbeck stator sleeve 169. Through the channel, the central Holbeck gap 173 is connected to the Holbeck gap 175 located radially inside. Thereby, a plurality of Holbeck pump stages engaging with each other inside and outside are connected in series with each other. A connection channel 179 leading to the exhaust port 117 may further be provided at the lower end of the Holbeck rotor sleeve 165 located radially inside.

[0056] The surfaces of the Holbeck stator sleeves 167, 169 that exhibit the aforementioned pumping action each have a plurality of Holbeck grooves that extend axially while spirally orbiting around the axis of rotation 151. On the other hand, the opposing side surfaces of the Holbeck rotor sleeves 163, 165 are smoothly formed and send the gas for the operation of the vacuum pump 111 forward in the Holbeck grooves.

[0057] For the rotatable shaft support of the rotor shaft 153, a rolling bearing 181 is provided in the region of the pump exhaust port 117, and a permanent magnet type magnetic bearing 183 is provided in the region of the pump intake port 115.

[0058] In the region of the rolling bearing 181, a conical splash nut 185 is provided on the rotor shaft 153. The splash nut 185 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 operating medium storage part. In another turbo molecular vacuum pump (not shown) that exists, a splash screw may be provided instead of the splash nut. Thereby, various configurations are realizable, so in the above relationship, the term "splash tip" is also used.

[0059] The actuating medium storage part has a plurality of absorbent disks 187 stacked one above the other. These disks 187 are impregnated with an actuating medium, for example a lubricant, for the rolling bearing 181.

[0060] During operation of the vacuum pump 111, the actuating medium is transmitted by capillary action from the actuating medium storage part via the scraping-off member to the rotating splash nut 185, and then, based on centrifugal force, is sent along the splash nut 185 towards the rolling bearing 181 in the direction of the increasing outer diameter of the splash nut 185. There, for example, the lubricating function is fulfilled. The rolling bearing 181 and the actuating medium storage part are surrounded in the vacuum pump by a trough-shaped insert 189 and a bearing cover 145.

[0061] The permanent magnet type magnetic bearing 183 has a bearing half 191 on the rotor side and a bearing half 193 on the stator side. These each have a ring stack, which consists of a plurality of rings 195, 197 of permanent magnets stacked axially one above the other. The ring magnets 195, 197 face each other while forming a radial bearing gap 199 therebetween. In this case, the rotor-side ring magnet 195 is arranged radially outward, and the stator-side ring magnet 197 is arranged radially inward. The magnetic field existing within the bearing gap 199 causes a magnetic repulsive force between the ring magnets 195, 197. That repulsive force realizes the radial shaft support of the rotor shaft 153. The rotor-side ring magnet 195 is supported by a support portion 201 of the rotor shaft 153. The support portion 201 surrounds the ring magnet 195 radially outward. The stator-side ring magnet 197 is supported by a stator-side support portion 203. The support portion 203 extends through the ring magnet 197 and is suspended from a radial support member 205 of the housing 119. Parallel to the rotation axis 151, the rotor-side ring magnet 195 is fixed by a cover element 207 connected to the support portion 203. The stator-side ring magnet 197 is fixed in one direction parallel to the rotation axis 151 by a fixed ring 209 connected to the support portion 203 and a fixed ring 211 connected to the support portion 203. A disc spring 213 may be further provided between the fixed ring 211 and the ring magnet 197.

[0062] Inside the magnetic bearing, an emergency bearing or a safety bearing 215 is provided. The emergency bearing or the safety bearing 215 rotates idly in a non-contact manner during the normal operation of the vacuum pump, and only engages when the rotor 149 is excessively displaced radially relative to the stator. Thus, a radial stopper for the rotor 149 is formed to prevent a collision between the structure on the rotor side and the structure on the stator side. The safety bearing 215 is configured as a non-lubricated rolling bearing and forms a radial gap together with the rotor 149 and / or the stator. Due to the gap, the safety bearing 215 does not engage during normal pump operation. When the safety bearing 215 engages during a radial displacement, and the radial displacement is dimensioned large enough, the safety bearing 215 does not engage during the normal operation of the vacuum pump, and at the same time is small enough to prevent a collision between the structure on the rotor side and the structure on the stator side in any situation.

[0063] 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 the rotor 149. The rotor shaft 153 of the rotor 149 extends through the motor stator 217. A permanent magnet assembly may be arranged radially outward or embedded in the portion of the rotor shaft 153 that extends through the motor stator 217. An intermediate chamber 219 is arranged between the motor stator 217 and the portion of the rotor 149 that extends through the motor stator 217. The intermediate 219 has a radial motor gap. Through the motor gap, the motor stator 217 and the permanent magnet assembly may magnetically influence each other to transmit the driving torque.

[0064] The motor stator 217 is fixed within the housing in a motor chamber 137 provided for the electric motor 125. Via a seal gas connection 135, seal gas (also referred to as purge gas, which may be, for example, air or nitrogen) can reach the motor chamber 137. Through the seal gas, the electric motor 125 can be protected against the process gas, for example, the corrosive part of the process gas. The motor chamber 137 may be evacuated via the pump exhaust port 117. That is, a vacuum pressure realized by an auxiliary vacuum pump connected to the pump exhaust port 117 acts, at least approximately, within the motor chamber 137.

[0065] 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. Thereby, in particular, a better seal of the motor chamber 217 against the Holweck pump stage located radially outside is achieved.

[0066] As will be described below with reference to FIG. 7 et seq., in the turbo molecular vacuum pump according to the present invention, for features not shown in FIG. 7 et seq., it may be configured as described above based on FIGS. 1 to 5.

[0067] FIGS. 6A and 6B are extremely simplified side views according to the prior art, specifically showing how the stator blades 20 of the metal plate are used in the conventionally used intake region of the turbo molecular vacuum pump.

[0068] The stator vane 20, which is manufactured by punching and bending and thus integrally formed, has a radially outer collar 24 (hereinafter also referred to as the outer collar), a radially inner collar (hereinafter also referred to as the inner collar) not shown, and a plurality of stator blades 22 located therebetween. The stator blades 22 are inclined by bending with respect to the blade plane 26 defined by the collar. According to FIG. 6A, the stator blades 22 project on both sides of the blade plane 26, and according to FIG. 6B, they project only on one side. The outer collar 24 is used to attach the stator vane 20 to a stator not shown by sandwiching the outer collar 24, for example, between two spacer rings. Thereby, the outer collar 24 also defines the mounting plane 32 at the same time, that is, in a known stator vane 20, the blade plane 26 and the mounting plane 32 coincide.

[0069] The metal plate stator vane 20 according to the present invention shown in FIG. 7 (see also FIGS. 8 and 9A) has stator blades 22 inclined toward one side between an inner collar not shown and a radially outer collar portion 24a (hereinafter the outer collar 24a) corresponding to a known metal plate stator vane (for example, as shown in FIG. 6B). The outer collar 24a located within the blade plane 26 is a component of a specially configured attachment portion 28. The attachment portion 28 has, in addition to the outer collar 24a, an end portion 30 and a transition portion 34. The end portion 30 defines a mounting plane 32 extending from the blade plane 26 with an axial spacing 52, and the transition portion 34 leads from the outer collar 24a, that is, from the blade plane 26 to the mounting plane 32 and extends axially (that is, parallel to the axial direction Z). This metal plate stator vane 20 according to the present invention can be manufactured in the same manner by punching and bending corresponding to a known metal plate stator vane. The spacing 52 between the blade plane 26 and the mounting plane 32 is, for example, 10 mm.

[0070] The end portion 30 is used to attach the stator vane 20 to the stator of a turbomolecular vacuum pump. This will be described in detail in connection with FIG. 9A.

[0071] As can be seen from FIG. 8, the halves of the stator blade 20 of the metal plate according to the two-piece invention (only one half is shown in FIG. 8 out of the halves, and the halves are formed corresponding to FIGS. 7 and 9A respectively) each have an annular shape, that is, both the outer collar 24a and the collar portion 24b (hereinafter referred to as the inner collar 24b) located radially inward in the radial direction R each have a semi-circular shape. An axially installed stator blade 22 is located between the inner collar 24b and the outer collar 24a. In the assembled state, the two inner collars 24b of the two halves of the stator blade 20 define a circular opening, through which a rotor (not shown) of the turbo molecular pump extends. In this case, the rotation axis of the rotor coincides with the central axis of the stator blade 20 formed by the two halves. In FIG. 8, a transition portion 34 extending in the axial direction Z and an end portion 30 extending radially outward from the transition portion 34 and perpendicular to the transition portion 34 can be further seen.

[0072] As shown in FIG. 9A, the end portion 30 of the mounting portion 28 of the stator blade 20 located closest to the pump inlet 36 is sandwiched between a spacer ring 50 and a shoulder portion 40 of the pump housing 38. Thereby, the blade plane 26 is located closer to the inlet plane 54 defined by the flange portion 42 and the pump inlet 36 than the mounting plane 32. Thereby, the distance 56 between the inlet plane 54 and the blade plane 26 can be reduced compared with a known pump, which advantageously affects the performance of the turbo vacuum molecular pump 10. This is because the flow loss is reduced.

[0073] An assembly region 44 is located between the shoulder portion 40 and the flange portion 42, and through the assembly region 44, the heads 48 of the circumferentially distributed mounting screws 46 are accessible, and the flange portion 42 can be screwed to a recipient (not shown) by the mounting screws 46.

[0074] The blade plane 26 is located at the height of the assembly region 44 that has not been used in the arrangement of the stator blades based on the fact that the inner diameter of the pump housing 12 decreases there.

[0075] The stationary blade 20 shown in FIG. 9A is the first stationary blade 20, i.e., the one closest to the pump intake 36, and forms part of a turbomolecular pump stage having a plurality of stationary blades 20 and a plurality of moving blades 58 of the rotor 14 that include rotor blades 16. Only the first moving blade 58 is shown in FIG. 9A. The other stationary blades not shown are each sandwiched between two spacer rings 50 and may be formed in a continuous disk shape as in the prior art or, similarly according to the present invention, with a mounting plane axially spaced from the blade plane.

[0076] The transition portion 34 has a cylindrical shape. In this case, since the outer collar 24a and the transition portion 34, and the transition portion 34 and the end portion 30 each form an angle of at least approximately 90°, the mounting portion 28 has an L-shape in a cross section including the axis of rotation 18, and the stationary blade 20 has an overall hat or pot shape.

[0077] FIGS. 9B and 9C show that two or more stationary blades 20 may be sandwiched between the spacer ring 50 and the shoulder portion 40. Another moving blade 58 having a rotor blade 16 is provided between the stationary blade 20 closest to the pump intake 36 and another or subsequent stationary blade 20. Another stationary blade 20 sandwiched between the spacer ring 50 and the shoulder portion 40 may be configured to have a mounting plane 32 axially spaced from the blade plane 26 in a form according to the present invention (see FIG. 9B). Moreover, another stationary blade 20 may be configured in a continuous disk shape as in the prior art (see FIG. 9C).

[0078] FIG. 10A shows that the stationary blade 20 may be sandwiched between two spacer rings 50 of the stator 12 at the end portion 30 of its mounting portion 28.

[0079] The embodiments of FIGS. 10B to 10E differ from the embodiment of FIG. 9A in the shape of the mounting portion 28 including the end portion 30 and the shape of the clamping surface of the spacer ring 50. These embodiments specifically show, by way of example, that the configuration of the stator blade 20 according to the present invention is not limited to the hat or pot shape according to FIG. 9A, and that the mounting portion 28 can in principle have any shape.

[0080] As can be seen similarly from FIGS. 10B to 10E, the spacer ring 50 can be adapted to the shape of the end portion 30 with a clamping surface in each case. In this case, the clamping surfaces of the spacer ring 50 do not have to be precisely adapted to the shape of each end portion 30. In each specific case, the end 30 of the stator blade 20 may be deformed when being clamped, and thus it may be acceptable or desirable to automatically adapt to the interacting clamping surfaces of the spacer ring 50.

[0081] According to FIG. 10B, the transition portion 34 is conical and transitions to the end portion 30 which is similarly conical and has the same cone angle. The free end of the end portion 30 defines the mounting plane 32 there.

[0082] In the embodiment of FIG. 10C, in contrast to the embodiment of FIG. 10B, an outer collar located within the blade plane 26 is not provided, that is, the transition portion 34 leads directly from the radially outer end of the blade 22 to the end portion 30.

[0083] According to FIG. 10D, both the transition portion 34 and the end portion 30 are curved. The curved course can in principle be arbitrarily selected. Here, the mounting plane 32 is defined by the apex of the end portion 30.

[0084] The embodiment of FIG. 10E corresponds to the embodiment of FIG. 10B, but in this case, no transition portion is provided. Instead, the end portion 30 sandwiched between the spacer rings 50 is directly connected to the outer collar 24a.

Explanation of reference numerals

[0085] 10 Turbo molecular vacuum pump 12 Stator 14 Rotor 16 Rotor blade 18 Axis of rotation 20 Stationary vane 22 Stator blade 24 Collar 24a, 24b Collar parts 26 Blade plane 28 Mounting part 30 End part 32 Mounting plane 34 Transition part 36 Pump intake port 38 Pump housing 40 Shoulder part 42 Flange part 44 Assembly area 46 Screw 48 Screw head 50 Spacer ring 52 Distance between blade plane and mounting plane 54 Intake port plane at pump intake port 56 Distance between intake port plane and blade plane 58 Moving vane 111 Turbo molecular pump 113 Intake port flange 115 Pump intake port 117 Pump exhaust port 119 Housing 121 Lower part 123 Electronics housing 125 Electric motor 127 Accessory connection part 129 Data interface 131 Current supply connection part 133 Intake port for ventilation 135 Seal gas connection part 137 Motor chamber 139 Coolant connection part 141 Bottom surface 143 Screw 145 Bearing cover 147 Fixed hole 148 Coolant pipeline 149 Rotor 151 Axis of rotation 153 Rotor shaft 155 Moving blade 157 Stationary blade 159 Spacer ring 161 Rotor hub 163 Holbeck rotor sleeve 165 Holbeck rotor sleeve 167 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 Disk 189 Insert 191 Bearing half on the rotor side 193 Bearing half on the stator side 195 Ring magnet 197 Ring magnet 199 Bearing gap 201 Support part 203 Support part 205 Radial strut 207 Cover element 209 Support ring 211 Fixed ring 213 Disc spring 215 Emergency bearing or safety bearing 217 Motor stator 219 Intermediate chamber 221 Wall part 223 Labyrinth seal

Claims

1. In a turbomolecular vacuum pump (10), A stator (12); at least one rotor (14), said rotor (14) having a plurality of rotor blades (16) distributed circumferentially, said rotor (14) being rotatably drivable about a rotation axis (18) to provide a pumping action; at least one stator vane (20), the stator vane (20) being attached to the stator (12) and interacting with the rotor (14) to provide a pumping action, the stator vane (20) having a plurality of circumferentially distributed stator blades (22), the stator blades (22) defining a blade plane (26); Equipped with The vane (20) has a mounting portion (28) having an end portion (30) for mounting to the stator (12), with which the vane (20) is mounted to the stator (12), the end portion (30) defining a mounting plane (32); The blade plane (26) and the mounting plane (32) extend perpendicular to and are spaced apart from one another along the rotation axis (18). A turbomolecular vacuum pump (10).

2. The vacuum pump (10) of claim 1, wherein the blade plane (26) is axially closer to the pump inlet (36) than the mounting plane (32).

3. the vane (20) is of integral construction; and / or the vane (20) is a stamped and / or bent part made of sheet metal or is produced by cutting a blank, in particular by sawing and / or milling a blank, A vacuum pump (10) according to claim 1 or 2.

4. the attachment portion (28) being formed by a collar (24) of the stator vane (20), the collar (24) having an end portion (30) radially outwardly and coupled to the stator blade (22) radially inwardly, or vice versa; and / or the mounting portion (28) has a radially outer collar portion (24a) or a radially inner collar portion (24b), the radially outer collar portion (24a) or the radially inner collar portion (24b) being located in the blade plane (26) and coupled to the stator blade (22); A vacuum pump (10) according to at least one of the preceding claims.

5. 4. A vacuum pump (10) according to claim 1, wherein the mounting portion (28) is formed by a free end portion of the stator blade (20).

6. the mounting portion (28) having a transition portion (34) leading from the blade plane (26) to the end portion (30) of the mounting portion (28); In particular, said transition portion (34) has at least partially the shape of a cylinder or a cone with said axis of rotation (18) as its central axis. A vacuum pump (10) according to at least one of the preceding claims.

7. 7. A vacuum pump (10) according to at least one of claims 1 to 6, wherein the end portion (30) of the mounting portion (28) has the shape of a cylinder or a cone having the axis of rotation (18) as a central axis, or has a curved course in a cross section including the axis of rotation (18).

8. 8. A vacuum pump (10) according to at least one of claims 1 to 7, wherein the mounting portion (28) has or comprises an L-shape in a cross section including the rotation axis (18), in particular the L-shape being formed by a transition portion (34) leading from the blade plane (26) to the end portion (30) of the mounting portion (28) and by the end portion (30) of the mounting portion (28).

9. 9. A vacuum pump (10) according to claim 1, wherein the vane (20) is part of a turbomolecular pump stage comprising a plurality of vanes (20) and a plurality of rotor blades (58) of the rotor (14), each having a plurality of rotor blades (16), the vanes (20) and the rotor blades (58) interacting to provide a pumping action.

10. The stator vane (20) is a stator vane (20) located axially closest to a pump intake port (36) among a plurality of stator vanes (20) spaced apart from one another in the axial direction of the stator (12); and / or In addition to the vane (20), one or more vanes (20) are provided that have the same structure as the vane (20), and in the one or more vanes (20), a blade plane (26) is located axially closer to a pump intake (36) than a mounting plane (32). A vacuum pump (10) according to at least one of the preceding claims.

11. 11. A vacuum pump (10) according to claim 1, wherein the stator vanes (20) are axially sandwiched in the stator (12) with the end portions (30) of the mounting portions (28).

12. Exactly one stator vane (20) is sandwiched between two spacer rings (50), each constructed as a separate component, or two or more stator vanes (20) are sandwiched between two spacer rings (50), each constructed as a separate component, and / or exactly one stator vane (20) is sandwiched between a spacer ring (50) constructed as a separate component and a shoulder portion (40) of the stator (12), in particular a shoulder portion (40) of a pump housing (38) forming part of the stator (12), or two or more stator vanes (20) are sandwiched between a spacer ring (50) constructed as a separate component and a shoulder portion (40) of the stator (12), in particular a shoulder portion (40) of a pump housing (38) forming part of the stator (12); A vacuum pump (10) according to at least one of the preceding claims.

13. said stator (12), in particular a pump housing (38) forming part of said stator (12), has in the region of the pump inlet (36) a flange portion (42) for establishing a mechanical connection with a recipient and a shoulder portion (40) axially spaced from said pump inlet (36), said shoulder portion (40) defining together with said flange portion (42) an assembly region (44) for at least one connecting element, in particular at least one screw (46), which is attached to said flange portion (42); Exactly one vane (20) is sandwiched between a spacer ring (50) and a shoulder portion (40) constructed as separate components, or two or more vanes (20) are sandwiched between a spacer ring (50) and a shoulder portion (40) constructed as separate components. A vacuum pump (10) according to at least one of the preceding claims.

14. 14. The vacuum pump (10) of claim 13, wherein the stator vane (20) is the stator vane (20) located axially closest to the pump inlet (36), the attachment plane (32) of the stator vane (20) is located in the region of the shoulder portion (40), and the blade plane (26) of the stator vane (20) is located between the pump inlet (36) and the shoulder portion (40).

15. A stator vane (20) for a turbomolecular vacuum pump (10), comprising: a plurality of stator blades (22) arranged in a circumferentially distributed manner, the stator blades (22) defining a blade plane (26); a mounting portion (28) having an end portion (30) by which the vane (20) is mountable to a stator (12) of the turbomolecular vacuum pump (10), the end portion (30) defining a mounting plane (32); The vane (20) defines a central axis, and the blade plane (26) and the attachment plane (32) extend perpendicular to and are spaced apart from one another along the central axis. Stator blade (20).

Images