TW202130912A - Rotor and multistage dry vacuum pump - Google Patents

Abstract

Rotor (7) for a multistage dry vacuum pump (1), the vacuum pump (1) including two shafts (5, 6) configured to turn in a synchronized manner in opposite directions in at least two pumping stages (1a-1f) to drive a gas to be pumped between an inlet (3) and an outlet (4), the rotor (7) including: a hub (9) configured to be engaged on one of the shafts (5, 6) of the vacuum pump (1), and at least one first and one second rotor element (8a, 8b) arranged along the hub (9), each rotor element (8a, 8b) extending in a respective pumping stage (1a-1f) and being configured to cooperate with a respective rotor element (8a, 8b) conjugate with another rotor (7) of the vacuum pump (1), the rotor elements (8a, 8b) and the hub (9) being made in one piece.

Description

Rotor and multi-stage dry vacuum pump

The present invention relates to the rotor of a multi-stage dry vacuum pump. The present invention is also related to a multi-stage dry vacuum pump provided with two such rotors.

Dry vacuum pumps include one or more pumping stages in series, in which gas is pumped to circulate between the inlet and the outlet. The conventional vacuum pump includes a pump with a rotary lobe (called a Lu's pump) and a pump with a claw (also known as a claw pump). The reason these vacuum pumps are called "dry" is that when they are running, the rotor rotates in the stator, and there is no mechanical contact between the rotors and between the rotor and the stator, which makes it unnecessary to use oil in the pumping stage.

In order to be able to perform machining and assembly, the rotor and stator of a dry vacuum pump are sometimes composed of an axial assembly of multiple elements. The stacking of this component needs to adjust its functional gap step by step. This type of dry pump structure actually requires independent machining of each element of the stator, and requires a long and delicate assembly operation, which consists of adjusting the position of the petals in each pressure chamber.

Given that the gap between the rotor's petals and the stator's walls is very small to ensure that each compression stage of the vacuum pump is sealed, it is obvious that the assembly is particularly long and delicate, and it is estimated that there are five or six This operation requires several hours of manpower on a dry vacuum pump. In order to achieve high-quality labor, the operation of this joint adjustment component is correspondingly time-consuming.

Another problem in the conventional multi-stage dry vacuum pump is that it is difficult to align the stator or rotor elements one by one. It should be noted that the error risk accumulates, which results in the difficulty of controlling the rotor and stator in the mass production process. Clearance. This configuration requires more precise production of parts, when the number of parts in the stack increases as the number of compression stages of the vacuum pump increases.

Also known, for example from the patent document US 6,572,351 (B2), is a vacuum pump structure with a stator composed of a half-shell assembled on a longitudinal assembly surface substantially parallel to the axis of the rotor. Therefore, due to the small number of interfaces to be aligned, the assembly of this pump must be faster. This structure also makes it possible to reduce the risk of accumulated alignment errors. This can reduce the cost of the vacuum pump and facilitate assembly.

In this configuration, the rotor can be a one-piece rotor, that is, machine directly on the shaft. This embodiment simplifies the production and assembly of moving parts of the vacuum pump. The machining tolerances of the components no longer accumulate like the petals installed on the shaft.

However, if an event occurs that affects the vacuum pump, for example, if the rotor and stator are stuck, the entire rotor and shaft (rotor-shaft) must be replaced. It is clear that a dry vacuum pump with a half-shell structure is disadvantageous because the entire vacuum pump must be replaced if only one component may be damaged.

In addition, the one-piece shaft rotor is supported by bearings arranged between the oil sump and the pumping stage. Disassembling the one-piece shaft rotor inevitably involves the complete disassembly of the entire vacuum pump, which makes such maintenance operations potentially costly.

Another disadvantage of the one-piece shaft-rotor is the lack of feasible modularization between different pump models. The one-piece shaft rotor has a certain production rigidity, which is not conducive to transposing the rotor into a similar configuration. Therefore, it is difficult to adapt the vacuum pump to specific customer needs without designing a brand-new pump.

An object of the present invention is to at least partially solve one of the above-mentioned disadvantages.

To this end, the present invention aims to provide a rotor for a multi-stage dry vacuum pump. The vacuum pump includes two shafts that are configured to rotate synchronously in opposite directions in at least two pumping stages to drive the pump. The gas pumped between the inlet and the outlet, the rotor includes: -A hub configured to mesh with one of the plurality of shafts of the vacuum pump, and -At least one first rotor element and one second rotor element, which are arranged along the hub, each rotor element extends in the respective pumping stage and is configured to interlock with the respective rotor element conjugated to the other rotor of the vacuum pump ( cooperate), the rotor element and the hub are made in one piece.

The one-piece and removable rotor can thus be replaced without the need to disassemble the entire shaft from its bearing. During maintenance, the shaft can be maintained at the position of at least two bearings of the vacuum pump, which can significantly reduce the disassembly and assembly time, as well as the corresponding interference period and cost. In terms of assembly, the vacuum pump can further benefit from the advantages of the one-piece rotor, while enabling easy and fast disassembly and assembly during continuous maintenance. Through a single machining operation, the rotor can be manufactured in one piece, which makes it easier to meet tolerances. In addition, the one-piece rotor enables the production of extremely thin rotor elements in the pumping stage, which are located at the outlet side of the multi-stage vacuum pump where the pressure is highest, which makes it possible to reduce the power consumption of the vacuum pump.

The rotor may further have one or more of the following features (independent or combined).

The hub may have the feature of a central penetrating housing that is configured to accommodate one end of the shaft at its engagement.

The hub may have the characteristics of a tapered central housing that is configured to accommodate an end of a complementary tapered shaft on which the energizing rotor can be driven.

The penetrating orifice can be arranged in the hub and/or in the rotor element to inject flushing gas.

The flushing gas (or neutral gas) may be nitrogen, for example.

The penetrating orifice arranged in the hub enables the flushing gas to be injected into the gap between the hub and the stator between the pumping stages, thereby forming a barrier to the pumped gas and possible powder or particles. In addition, the penetrating orifice can be exhausted at the height of the rotor element in the pressure chamber of the vacuum pump to dilute the pumped gas.

The hub may have the characteristics of a nose at one axial end of the rotor, which is located on one side of the rotor element, which is intended to be configured in the final pumping stage communicating with the outlet and in the driving part of the vacuum pump On this side, the seal is intended to be arranged between the nose of the rotor and the stator of the vacuum pump.

The nose of the rotor coupled with the seal can ensure the seal between the final pumping stage and the driving part of the vacuum pump. This is especially necessary to prevent pollution caused by contaminated gas or particles from the dry pumping part. Ensure the integrity of the lubricated bearings of the drive components. The seal obtained in this way makes it possible to increase the service life of the driving parts of the vacuum pump without maintenance, which can be as long as 8 to 10 years. During frequent maintenance periods (for example, once every two years), the rotor can be replaced or cleaned without disassembling the bearings of the drive components.

The conjugate joint rotor element has, for example, lobes with the same profile.

According to an embodiment, the at least one rotor element includes at least two lobes.

The petals may be characterized by a helical twist about the longitudinal axis.

By improving the volumetric efficiency, the spirally twisted valve profile enables an increase in the effective pumping rate. This embodiment further promotes the vertical configuration of the vacuum pump, in which the axis is oriented vertically, which enables further reduction of the footprint and facilitates the pumping of powder or particles.

The petals of at least one rotor element may be hollow.

The hollow flap can reduce the weight of the vacuum pump. In addition, the hollow rotor element enables the reduction of thermal inertia and drives less mass to move, which can reduce the risk of deterioration that may occur when the rotor is touched or stuck.

The contours of the rotor elements can be of the same type or different types. "Same type of profile" means rotor elements with the same general shape. It should be understood that the thickness and/or radial dimension of the same type of rotor elements may vary between different pumping stages, especially those with the same general shape. The production volume decreases with the pumping stage (or remains the same).

According to an embodiment, the first rotor element intended to be arranged in the first pumping stage communicating with the inlet of the vacuum pump includes at least two lobes with helical twist characteristics, and the at least one second rotor element includes at least two straight Style petals.

According to another example, the rotor includes six straight three-lobed rotor elements.

The object of the present invention is also a multi-stage dry vacuum pump, which includes: -Two shafts configured to rotate synchronously in opposite directions in at least two pumping stages of the vacuum pump to drive the gas to be pumped between the inlet and the outlet, and -The two rotors mentioned above are detachable and meshed with the respective shafts of the vacuum pump.

The vacuum pump may further have one or more of the following features (independent or combined).

According to an embodiment, the vacuum pump is a main vacuum pump configured to discharge pumped gas at atmospheric pressure.

According to another embodiment, the vacuum pump is a dry vacuum pump with two or three pumping stages, the two or three pumping stages are connected upstream of the main vacuum pump, and the outlet pressure is generated by the main vacuum pump.

The shafts can each be supported by at least two bearings located on either side of the pumping stage.

According to another example, the shaft is cantilever mounted. The fixed part of the cantilever shaft enables the simple engagement and disengagement of the rotor and the shaft without disassembling the shaft from any bearing.

The shaft is supported by, for example, a support on the side of the final pumping stage communicating with the outlet, and on this side of the driving part of the vacuum pump. This is particularly empowered to limit the transfer of lubricant from the oil sump to the pumping stage. It is because of the lower pressure difference between the oil sump under normal pressure and the final pumping stage.

According to an embodiment, in the case where the hub of the rotor is a hollow penetrating hub, the vacuum pump may include at least one expandable clamping ring which is accommodated in the central penetrating shell (or hole) of the hub and It is arranged between one end of the shaft and the hub to fix the rotor to the shaft through a double cone assembly. Each rotor can therefore be set at a single angle and assembled on its respective shaft through a clamping operation using an expandable clamping ring. Assembling and disassembling the rotor will become simpler and faster. Therefore, by simplifying the assembly operation in this way, there will be more opportunities to automate the assembly operation.

In the case where the hub of the rotor is a hollow penetrating hub, the vacuum pump may include a plug-seal which is installed in the central penetrating shell (or hole) of the hub of the rotor and It is configured to close the center penetrating shell of the hub in a sealed manner. The plug seal makes it possible to prevent rusty gas, powder, etc. from entering the central penetrating housing, which may corrode or damage the shaft or the expandable clamping ring. The central penetration housing can then experience an increased flushing gas pressure.

According to another embodiment, at least one end of the shaft is tapered and the rotor is driven to the tapered end of the shaft by means of a tapered central housing complementary to the hub of the rotor.

The methods for fixing and sealing the rotor to the shaft are simple and versatile. Especially through the use of a combination of different rotor element contours, this enables the use of different pumping techniques (such as straight-lobe or spiral-lobe pumping). This has real flexibility in the production of vacuum pumps used, and has the efficiency based on the same mechanical drive components.

According to an embodiment, the hub has the characteristics of a nose at one axial end of the rotor, the nose is located on one side of the rotor element, which is arranged in the final pumping stage communicating with the outlet, and in the vacuum pump On the side of the driving part, the vacuum pump further includes at least one seal, which is arranged between the nose of the rotor and the stator.

The seal may include a rubbing ring seal.

The vacuum pump may include a rubbing ring arranged between the nose of the rotor and the rubbing ring seal. The rubbing ring makes it possible to avoid replacing the entire rotor when there is local wear on the surface rubbed against the rubbing ring seal.

The orifice can be formed in the rubbing ring seal for injecting purge gas. Because the rotor is a multi-stage rotor, and because the nose of the rotor is located on one side of the higher pressure pumping stage, flushing gas can be injected into the rubbing ring seal. The lower pressure level energizes to ensure the efficiency of the pump at the inlet. Therefore, the flushing gas injected into the rubbing ring seal ensures that the protection of the support through the improved seal is improved without or only slightly affecting the pumping efficiency.

According to another example, the seal includes a dynamic seal ring characterized by a disk arranged facing the transverse wall of the stator, and the vacuum pump includes a flushing gas inlet discharged between the transverse wall and the disk. In operation, injecting flushing gas between the disk and the lateral wall creates a gas screen, which forms a barrier to the gas to be pumped and lubricant.

According to another embodiment, wherein the hub does not have the feature of a nose at the axial end of the rotor, the dry vacuum pump includes a fixing and sealing ring mounted on the shaft close to one axial end of the rotor on one side of the rotor The rotor element is intended to be configured on the side of the driving part of the vacuum pump in the final pumping stage communicating with the outlet.

According to the first example, the vacuum pump further includes at least one rubbing ring seal arranged between the fixing and sealing ring and the stator. The orifice can be formed in the rubbing ring seal for injecting purge gas.

According to a second example, the fixing and sealing ring includes a disk arranged facing the transverse wall of the stator, and the vacuum pump includes a flushing gas inlet for discharging gas from the nose of the fixing and sealing ring between the transverse wall and the disk.

On the one hand, the fixing and sealing ring thus ensures the function of sealing between the rotor and the stator, and on the other hand, the adjustment of the axial position of the rotor and the adjustment of the gap between the rotor and the stator. The fixing and sealing ring ensures the simplification of axial adjustment, because it is easier to redesign or adjust the length of the ring than to redesign or adjust the length of the rotor. In addition, the fixing and sealing rings promote anti-friction and/or protective coating deposition.

According to an embodiment, the vacuum pump comprises at least two attached rotor elements, which are fixed to respective shafts in the pumping stage. It is also possible to adapt the pump model only by changing the attached rotor element of the pumping stage.

The following embodiments are examples. Although this specification refers to one or more embodiments, this does not necessarily mean that each reference is related to the same embodiment, or that the feature is only applicable to a single embodiment. Single features of different embodiments can also be combined or interchanged to provide other embodiments.

"Upstream" refers to an element placed in front of another element with respect to the circulation direction of the gas to be pumped. Conversely, "downstream" refers to a component placed behind another component with respect to the circulation direction of the gas to be pumped.

The longitudinal or axial direction of the vacuum pump is defined as the direction in which the shaft extends.

The present invention is applicable to any type of multi-stage dry vacuum pump, that is, the pump includes at least two pumping stages, for example, includes two to ten pumping stages. The vacuum pump can be a main vacuum pump configured to release pumped gas at atmospheric pressure, or a dry vacuum pump with two or three pumping stages connected upstream of the main vacuum pump, and The outlet pressure is produced by the main vacuum pump.

Figure 1 shows an embodiment of a multi-stage dry vacuum pump 1, which includes a stator 2 (or pump body) forming at least two pumping stages 1a-1f (here, six pumping stages 1a-1f). The sending stage is assembled in series between the inlet 3 and the outlet 4 of the vacuum pump 1, and pumpable gas circulates therein. The pumping stage 1a communicating with the inlet 3 of the vacuum pump 1 is a lower pressure stage, and the pumping stage 1f communicating with the outlet 4 is a higher pressure stage.

The vacuum pump 1 further includes two shafts 5, 6 parallel to each other and two rotors 7 meshed on the respective shafts 5, 6 of the vacuum pump 1, which are configured to rotate synchronously in opposite directions in the pumping stages 1a-1f. The rotors 7 each include a hub 9 configured to engage with one of the shafts 5, 6 of the vacuum pump 1, and at least a first and a second rotor element 8a, 8b, which are arranged along the hub 9, each rotor element 8a, 8b extend in the respective pumping stages 1a-1f. Each rotor element 8a, 8b is configured to interlock with the respective conjugated rotor element 8a, 8b of the other rotor 7.

Each pumping stage 1a-1f delimits a pressure chamber 10 of the stator 2 which houses the two rotors of the vacuum pump 1 conjugated to the rotor elements 8a, 8b. The chamber 10 has its own inlet and outlet. During the rotation, the gas sucked from the inlet is trapped in the volume created by the rotor elements 8a, 8b and the pressure chamber 10 of the pumping stages 1a-1f, and the gas is then compressed and driven into the outlet and secondary.

The pressure chambers 10 of successive pumping stages 1a-1f are connected in series with each other through at least one respective interstage passage 11 which connects the outlet of the pressure chamber 10 of the previous pumping stage to the inlet of the secondary pressure chamber 10. The inter-stage passage 11 is, for example, arranged in the body of the stator 2, for example, in the body of the stator 2 together with the pressure chamber 10. For example, each pumping stage has two interstage passages 11, which are connected in parallel between the outlet and the inlet of the compression stage 10 and are arranged on either side of the compression chamber 10.

The pumping stages 1a-1f have the characteristic of generating volume (that is, the pumped gas volume), which decreases (or equals) with the pumping stage. The first pumping stage 1a has the highest generating flow rate and the final pumping stage 1f has the lowest flow rate.

In operation, the shafts 5, 6 are driven to rotate by a drive member, which includes a motor M for driving the rotor, a gear for synchronizing the rotor, and a bearing that supports the shaft of the rotor.

The motor M of the vacuum pump 1 is mounted on one of the shafts 5, 6 (for example, at one end of the vacuum pump 1), such as on the side of the outlet 4 of the vacuum pump 1.

The shafts 5 and 6 are supported by bearings and are lubricated by lubricant from the oil groove 12 of the driving part of the pump 1, and the oil groove 12 is provided between the motor M and the stator 2. Lubricant especially enables the lubrication of the rolling member 13 of the bearing and the synchronous gears of the shafts 5 and 6 of the vacuum pump 1. The dry vacuum pump 1 typically rotates above 40 Hz, such as between 50 Hz and 150 Hz.

The reason why the vacuum pump 1 is called "dry type" is that when it is running, the rotor 7 rotates in the stator 2, and there is no mechanical contact between the rotor 2 and between the rotor and the stator. Oil.

The stator 2 is formed by a plurality of stator elements, for example. The stator 2 includes, for example, two half-shells 2a, 2b (only one is shown in the drawings), and the half-shells are assembled radially on the surface of the longitudinal assembly, the surface being, for example, parallel to the shafts 5 and 6 of the vacuum pump 1, And it includes a seal support 2c and a bearing support frame 2d arranged between the half shells 2a, 2b of the pumping stages 1a-1f and the oil groove 12.

The vacuum pump 1 further includes a lubricant sealing device 14 which is provided between the driving part and the dry pumping part (in which gas is circulated). The energizing shaft of the sealing device 14 can rotate in the dry pumping part while restricting the transfer of lubricant. The sealing device 14 is arranged at the height of the shaft passage and carried by the sealing member support 2c. The sealing device 14 includes, for example, at least one seal (such as a non-rubbing dynamic seal), or at least one rubbing ring seal (such as a lip seal), or a combination of the foregoing.

As can be seen from the example in FIG. 1, the hub 9 has features such as a central penetrating housing 15 (or hole), which has the general shape of a cylinder, for example, in which it engages with one of the shafts 5 and 6 of the vacuum pump 1 ( Especially at one end of the shaft 5a, 6a). The rotor 7 meshed with the shafts 4 and 5 rotates with the shafts 5 and 6.

The rotor elements 8a, 8b and the hub 9 are made in one piece. The one-piece and removable rotor 7 can therefore be replaced without disassembling the entire shafts 5, 6 from their bearings. During maintenance, the shafts 5 and 6 can be maintained at the positions of at least two bearings of the vacuum pump 1, which can significantly reduce the disassembly and assembly time, and the corresponding interference period and cost. In terms of assembly, the vacuum pump 1 can further benefit from the advantages of the one-piece rotor 7, and at the same time, it can be easily and quickly disassembled and assembled during future maintenance. Through a single machining operation, a one-piece rotor 7 can be manufactured, which makes it easier to meet tolerances. In addition, the one-piece rotor 7 enables the production of ultra-fine rotor elements 8a, 8b in the pumping stages 1e-1f. The ultra-fine rotor elements are located on the outlet 4 side of the multi-stage vacuum pump 1 where the pressure is highest. This makes it possible to reduce the power consumption of the vacuum pump 1. Another advantage is that due to the removable nature of the rotor 7, the rotor 7 can be easily adapted to customer needs by changing the coating of the rotor elements 8a, 8b to protect the rotor 7 or improve sliding in certain applications.

According to an embodiment, the shafts 5, 6 may each be supported by at least two bearings located on either side of the pumping stages 1a-1e. However, in order to facilitate further assembly and disassembly of the rotor 7, the shafts 5 and 6 can be cantilevered. In other words, the shafts 5, 6 are supported by bearings located on only one side of the stator 2 of the pumping stages 1a-1f. This side is, for example, the outlet 4 side of the vacuum pump 1, which is energized to limit the transfer of lubricant from the oil tank 12 to the pumping stages 1a-1f. This is because the oil tank 12 under normal pressure and the final pumping stage 1f The reason for the lower pressure difference.

For example, there is no guiding device on the other side (on the side of the inlet 3). The cantilever-mounted shafts 5, 6 are particularly feasible due to the high mechanical strength of the one-piece rotor 7. The shafts 5 and 6 cantilevered to enable the simple engagement and disengagement of the rotor 7 and the shafts 5 and 6 without disassembling the shafts 5 and 6 from any bearings.

In order to fix the hollow rotor 7 to the shafts 5, 6, the vacuum pump 1 includes at least one expandable clamping ring 17, for example. The expandable clamping ring 17 is accommodated in the central penetrating housing 15 of the hub 9, and is radially arranged between one end 5a, 6a of the shafts 5, 6 and the hub 9 to pass through the double cone assembly. Fix the rotor 7 to the shafts 5, 6. Therefore, there are two expandable clamping rings 17 for fixing each rotor 7 to the respective shaft 5, 6 (Figures 1 to 3). Therefore, by wedging the expandable clamping ring 17, the connection between the shafts 5 and 6 and the hub 9 can be achieved. The expandable clamping ring 17 enables mechanical clamping and torque transfer from the shafts 5 and 6 to the rotor 7.

As can be better seen from Figure 4a, the expandable clamping ring 17 typically includes two tapered split rings 18a, 18b, for example, opened by three respective axial grooves regularly distributed. The tapered rings 18a, 18b are coaxially installed inside the other. The expandable clamping ring 17 also includes at least one nut (such as a single axial nut 20) that is coupled with the conical rings 18a, 18b.

The expandable clamping ring 17 is mounted on the ends 5a, 6a of the shafts 5, 6, the latter being thinned, for example, radially, which allows a wrench inserted into the central penetration housing 15 of the rotor 7 to access the nut 20, the latter For example, it is also locally enlarged in the radial direction. At assembly time, tighten the nut 20 to clamp the two rings 18a, 18b together, which will expand the outer conical ring 18b, while the inner conical ring 18a imposes more on the ends 5a, 6a of the shafts 5, 6 The high pressure causes the rotor 7 to be wedged onto the shafts 5 and 6, as depicted in the schematic diagram of Fig. 4b. Each rotor 7 can therefore be assembled on the respective shafts 5 and 6 in a single clamping and angle setting operation by means of the expandable clamping ring 17. Assembling and disassembling the rotor 7 will become simpler and faster. Therefore, by simplifying the assembly operation in this way, there will be more opportunities to automate the assembly operation.

The shafts 5 and 6 extend in the center penetrating housing 15 of the rotor 7, for example, leaving empty spaces between the ends 5 a and 6 a of the shafts 5 and 6 and the ends of the rotor 7.

The wheel hub 9 may further have the feature of a nose 28 at one axial end of the rotor 7, which is located on one side of the rotor element 8b, which is intended to be configured in the final pumping stage 1f communicating with the outlet 4 , And on this side of the drive part of the vacuum pump 1 (Figure 1). The nose portion 28 is specially energized by at least one sealing member 29 of the vacuum pump 1 which can be arranged between the nose portion 28 of the rotor 7 and the stator 2 to seal the passage between the latter.

The nose 28 of the rotor 7 coupled with the seal 29 can ensure the seal between the final pumping stage 1f and the driving part of the vacuum pump 1, which is particularly necessary to prevent contaminated gases or particles from the dry pumping parts The resulting contamination ensures the integrity of the lubricated bearings of the drive components. The seal obtained in this way makes it possible to increase the service life of the driving parts of the maintenance-free vacuum pump 1, which can be as long as eight to ten years. During frequent maintenance periods (for example, once every two years), the rotor 7 can be replaced or cleaned without disassembling the bearings of the driving parts.

The seal 29 may be a rubbing annular seal and/or a non- rubbing dynamic seal.

In the first embodiment shown in Figs. 1 to 8, the sealing member 29 includes a lip or double-lip rubbing ring seal (Fig. 5). The lip of the rubbing ring seal is made of PTFE, for example. It is installed in the ring of an annular seal made of aluminum or stainless steel, for example. The ring rubbing the annular seal is fixed to the stator 2 and the lip rubs against the rotating nose 28.

The orifice 30 may be formed in the rubbing ring seal for injecting purge gas, especially between the lips. The orifices 30 are, for example, regularly distributed on the seal, and an annular gas barrier is created between the dry pumping part and the driving part of the pump 1 during operation.

Because the rotor 7 is a multi-stage rotor, and because the nose 28 of the rotor 7 is located on the side of the higher pressure pumping stage 1f, flushing gas can be injected into the rubbing ring seal. The lower pressure level makes it possible to ensure the pumping efficiency at the inlet 3. Therefore, through the improved seal, the flushing gas injected into the rubbing ring seal ensures improved protection of the bearing without or only slightly affecting the pumping efficiency.

In addition, the vacuum pump 1 may include a mechanism for injecting flushing gas into the central penetration housing 15 of the rotor 7. The flushing gas can, for example, pass through channels (not shown) formed in the shafts 5, 6.

A penetrating orifice may be formed in the hub 9 to inject flushing gas into the gap between the hub 9 and the stator 2 between the pumping stages 1a-1f. In operation, the flushing gas injected through the rotating orifice forms a gas screen, which forms a barrier to the pumped gas and any powder or particles.

In addition, the penetrating orifice can be exhausted in the pressure chamber 10 of the vacuum pump 1 at the height of the rotor elements 8a, 8b to dilute the pumped gas.

The vacuum pump 1 may further include at least one plug seal 21 which is installed in the central penetrating shell 15 of the hub 9 of the rotor 7 and configured to seal the central penetrating shell of the hub 9 in a sealed manner Body 15 (Figures 2 and 3). The plug seal 21 makes it possible to prevent rusty gas, powder, etc. from entering the central penetrating housing 15, which may corrode or damage the shafts 5, 6 or the expandable clamping ring 17. The pressure of the flushing gas in the central penetrating shell 15 can then be increased.

As can be better seen in FIG. 6, the plug seal 21 includes, for example, a main body 22 whose general shape matches the general shape of the central penetrating housing 15, for example, a cylindrical shape. The main body 22 is made of steel, for example.

The plug seal 21 also includes an O-ring seal 23 disposed between the main body 22 and the central penetrating housing 15, which is disposed in the circumferential groove 25 of the main body 22, for example. The O-ring seal 23 is made of, for example, a fluoroelastomer, such as FKM (or FPM) or FFKM (or FFPM).

According to the first embodiment, the plug seal 21 is fixed to the shafts 5 and 6 of the vacuum pump 1. For this purpose, the main body 22 of the plug seal 21 has features such as an axial rod 24 configured to be inserted in complementary axial bores of the ends 5a, 6a of the shafts 5, 6 in order to The positioning of the plug seal 21 on the shafts 5, 6 is facilitated. The axial rod 24 is threaded, for example, and is clamped in the threaded axial holes of the shafts 5 and 6 by means of tools that cooperate with two blind holes 26 formed on the outer surface of the main body 22, for example.

These methods for fixing and sealing the rotor 7 to the shafts 5 and 6 are simple and versatile. This enables the use of different pumping techniques (such as straight-lobe or spiral-lobe pumping), and further enables the use of combinations of different rotor element profiles. This has real flexibility in the production of vacuum pumps used, and has the efficiency based on the same mechanical drive components.

As can be better seen in Fig. 7, the conjugated rotor elements 8a, 8b have, for example, the characteristics of a petal 16 having the same profile.

At least one rotor element 8a, 8b includes, for example, at least two lobes 16, and may include, for example, two, three, four, five, or more lobes 16. The petals 16 are regularly distributed in the circumferential direction.

In addition, the petals 16 of several rotor elements 8a may be hollow. For example, the petals 16 of the first or the first two more bulky pumping stages 1a, 1b with less risk of leakage may be hollow. However, all the rotor elements 8a of the rotor 7 may be hollow. The rotor elements 8a, 8b can have different sized cavities. For example, the petals 16 of the rotor elements 8a of the so-called low-pressure pumping stages 1a-1c are pierced by holes having a larger diameter than the petals 16 of the rotor elements 8b of the so-called high-pressure pumping stages 1d-1f. The hollow flap 16 is capable of reducing the weight of the vacuum pump 1. Similarly, the hollow rotor element 8a enables the reduction of thermal inertia and drives less mass to move, which can reduce the risk of deterioration that may occur when the rotor 7 is touched or stuck.

The rotor elements 8a, 8b of the multi-stage rotor 7 may have the same type or different types of profile features. "Same type of profile" means rotor elements 8a, 8b with the same general shape. It should be understood that the thickness and/or radial dimension of the same type of rotor elements 8a, 8b can vary between different pumping stages 1a-1f In particular, the production volume of the pumping stages 1a-1f decreases (or equals) with the pumping stages 1a-1f.

In the example of Figures 1 to 8, the contours of the six rotor elements 8a, 8b of the rotor 7 are therefore all of the same type. The rotor elements 8a, 8b of the rotor 7 and the conjugated rotor elements 8a, 8b are three-lobed rotor elements, that is, they each include three lobes 16. This type of vacuum pump 1 including two rotors 7 (each having the characteristics of six straight three-lobe rotor elements) is a main vacuum pump configured to discharge pumped gas at atmospheric pressure.

Other embodiments are feasible.

Therefore, in the example of FIG. 9, the rotor elements 8a, 8b and the conjugated rotor elements 8a, 8b each include two diametrically opposed lobes 16. The two-lobed configuration in which the cross-sections of the rotor elements 8a and 8b are essentially the shape of the number 8 is also called the Roots configuration. In addition, the profiles of the six rotor elements 8a, 8b are all of the same type.

Figures 10 and 11 show two other embodiments.

In these examples at least one rotor element 8a comprises at least two lobes 16 characterized by a helical twist about a longitudinal axis, which is also the axis of rotation of the rotor 7. The helical twist is, for example, less than a quarter turn. For example, it is between 60˚ (inclusive) and 90˚ (inclusive).

By improving the volumetric efficiency, the spirally twisted valve profile enables an increase in the effective pumping flow rate.

In addition, in these examples, the contours of the rotor elements 8a, 8b of the rotor 7 are different.

For example, the first rotor element 8a intended to be arranged in the first pumping stage 1a communicating with the inlet 3 of the vacuum pump 1 includes at least two lobes 16 with helical twist characteristics, and the at least one second rotor element 8b includes at least two straight lobes 16.

The vacuum pump 1 is, for example, a dry vacuum pump with two or three pumping stages. The two or three pumping stages are connected upstream of the main vacuum pump, and the outlet pressure is generated by the main vacuum pump. The rotor 7 includes, for example, a first rotor element 8a and one or two second rotor elements 8b, the first rotor element 8a includes two lobes 16 with helical twists, and the second rotor element 8b includes three straight lobes 16 ( Figure 10). According to another example, the rotor 7 includes a first rotor element 8a and one or two second rotor elements 8b, the first rotor element 8a includes three lobes 16 with helical twists, and the second rotor element 8b includes three straight Style petal 16 (Figure 11). The rotor 7 has a nose 28 at one of the axial ends of the rotor 7 on one side of the rotor element 8b, which is intended to be arranged in the final pumping stage 1f communicating with the outlet 4 and in the vacuum pump On that side of the drive part.

According to another example, the vacuum pump 1 is a main vacuum pump configured to discharge pumped gas at atmospheric pressure. The rotor 7 includes a first rotor element 8a and a number of between four and eight second rotor elements 8b, the first rotor element 8a includes two or three lobes 16 with helical twists, and the second rotor element 8b includes three A straight petal 16. The rotor 7 has the characteristics of a nose 28 at one axial end of the rotor 7, which is located on one side of the rotor element 8b, which is intended to be arranged in the final pumping stage communicating with the outlet and in the vacuum pump On that side of the drive part.

A modified embodiment of the sealing mechanism between the rotor 7 and the driving part of the vacuum pump 1 will now be described.

Figures 12a and 12b show a first variant embodiment.

In this example, the vacuum pump 1 includes a rubbing ring 35 arranged between the nose 28 of the rotor 7 and the rubbing ring seal.

The rubbing ring 35 is made of hard steel or martensitic steel, for example. The rubbing ring 35 may have coating characteristics, for example, to reduce the wear caused by rubbing, and to improve the protection of the pumped gas. In this case, applying coating to the small rubbing ring 35 is simpler than applying coating to the nose 28 of the rotor 7.

The rubbing ring 35 is mounted on the nose portion 28 by, for example, an O-ring seal 36 arranged radially between the rubbing ring 35 and the nose portion 28. The O-ring seal 36 is installed in the annular groove 37 of the rubbing ring 35, for example.

The rubbing ring 35 makes it possible to avoid replacing the entire rotor 7 when there is local wear on the surface rubbed against the rubbing O-ring seal. In fact, over time, only the surface in contact with the rubbing O-ring seal may wear. The wear surface on the removable rubbing ring 35 can then be replaced without replacing the rotor 7.

According to another embodiment, the rubbing ring comprises a ceramic type deposit, which is deposited, for example, using a plasma torch. This deposit is easy to resurface during maintenance.

Figures 13a, 13b and 13c show a second variant embodiment of the sealing method, the sealing mechanism being between the nose 28 of the rotor 7 and the driving part of the vacuum pump 1.

In this variant, the seal 38 coupled with the nose 28 of the rotor 7 is a non-rubbing dynamic seal.

According to an embodiment, the seal 38 includes a dynamic sealing ring (Figure 13b). The dynamic seal ring is mounted on the nose portion 28 of the rotor 7 by, for example, an O-ring seal 41 arranged radially between the dynamic seal ring and the nose portion 28 (FIG. 13a). The O-ring seal 41 is installed in the annular groove of the dynamic seal ring, for example.

The dynamic sealing ring has the characteristics of a disc 42 which faces the transverse wall 43 of the stator in the vacuum pump 1. The lateral wall 43 may be formed in a complementary bearing surface formed in the stator (Figure 13c).

The surface of the disc 42 facing the stator 2 may have the characteristics of a spiral groove 44, which enables the flushing gas to be better distributed around the disc 42 (Figure 13b).

The dynamic seal ring is made of, for example, alumina ceramics _{such as Al 2} O _{3 or nitride-based ceramics such as Si 3} N ₄ , or hard steel or Asada loose iron steel or includes coatings of the above.

The vacuum pump 1 further includes a flushing gas inlet 45 formed in the stator 2 to discharge gas between the transverse wall 43 and the disk 42 in a direction perpendicular to the rotation axis of the rotor 7.

In operation, injecting flushing gas between the disk 42 and the lateral wall 43 of the stator 2 will create a gas screen between the rotating disk 42 and the fixed lateral wall 43 of the stator 2.

The gas screen forms a barrier to the gas and lubricant to be pumped. Therefore, the seal 38 produces a "non-friction dynamic" sealing property between the stator 2 and the rotor 7.

14a, 14b and 14c show a third variant embodiment of the sealing mechanism, which is between the rotor 7 and the driving part of the vacuum pump 1.

In this example, the hub 9 does not have a nose 28 at the axial end of the rotor 7 (Figure 14c). On the other hand, the vacuum pump includes a setting and sealing ring 46 which is mounted on the shaft 5 against an axial end of the rotor 7 and on the rotor element 8b of the rotor 7 On the side, the rotor is intended to be arranged in the final pumping stage 1f communicating with the outlet 4, and on this side of the driving part of the vacuum pump 1. The fixing and sealing ring 46 thus forms a “nose” mounted on the rotor 7.

The fixing and sealing ring 46 is mounted on the shaft 5 through an O-ring seal 47 axially arranged between the fixing and sealing ring 46 and the rotor 7, for example. The O-ring seal 47 is, for example, installed in the annular groove 48 of the fixing and sealing ring 46 (Figure 14b).

According to the first example, the vacuum pump 1 further includes at least one rubbing ring seal 29, such as a lip seal radially arranged between the fixing and sealing ring 46 and the stator 2 (Figure 14a). The ring rubbing the annular seal is fixed to the stator 2 and the lip rubs against the rotating fixed and sealing ring 46. Orifices can be formed in the rubbing ring seal to inject flushing gas.

According to a second example not shown, the fixing and sealing ring 46 includes a disc, which is in the vacuum pump 1 and faces the transverse wall 43 of the stator 2. The vacuum pump 1 includes a flushing gas inlet 45, which is located oppositely The fixing between the transverse wall 43 and the disc and the nose of the sealing ring 46 discharge gas to create a gas screen between the rotating disc and the fixed transverse wall 43 of the stator 2. As mentioned above for the dynamic seal ring, the surface of the disk facing the stator 2 fixed and the seal ring 46 may have the characteristics of a spiral groove.

In addition to providing a sealing function between the rotor 7 and the stator 2, the fixing and sealing ring 46 also provides an adjustment and setting function for positioning the rotor 7 in the axial direction and for adjusting the gap between the rotor 7 and the stator 2. The fixing and sealing ring 46 ensures the ease of axial adjustment, because it is easier to redesign or adjust the length of this ring 46 than to redesign or adjust the length of the entire rotor 7. Similarly, the fixing and sealing ring 46 promotes the possible deposition of anti-friction and/or protective coatings due to its small size relative to the size of the rotor 7.

Figures 15a, 15b and 15c show modified embodiments of the plug seal.

In this example, the plug seal 21 is fixed to the rotor 7 by means of at least two screws 39 (for example, four screws), for example.

To this end, the main body 22 of the plug seal 21 has, for example, the characteristics of a frame 27 provided with a fixing hole 40. Complementary bearing surfaces are formed in the end of the rotor 7. By passing through the fixing hole 40 of the plug seal 21 and tighten the screw 39 on the threaded hole formed on the complementary bearing surface of the rotor 7, the plug seal 21 is fixed to the rotor 7.

This embodiment enables the plug seal 21 to be fixed in the central penetration housing 15 in a firm manner.

Figure 16 shows another embodiment of the cantilever mounting of the shaft.

The rotor 7 can be fixed on the cantilever shafts 5 and 6 in other ways, such as a "Morse taper" type fixing device used on a machine tool, as shown in FIG. 16.

In this case, at least one end portion 5a, 6a of the shafts 5, 6 is tapered. The hub 9 of the rotor 7 further has the characteristics of a complementary tapered central housing 32, which energizes the rotor 7 to be driven onto the tapered ends 5a, 6a of the shafts 5, 6.

The rotor 7 is force-fitted to the ends 5a, 6a of the shafts 5, 6, which significantly deforms the tapered central housing 32 of the rotor 7 and holds the rotor 7 on the shafts 5, 6.

As in the previous example, the vacuum pump 1 may include at least one plug seal 21 that is installed in the hub 9 and configured to seal the hub in a sealed manner when the hub penetrates the shell. The central shell 32 of the hub 9 is to ensure that no corrosion gas, powder, etc. enter.

When the rotor 7 needs to be removed for maintenance, in an operation example, the plug seal 21 is removed and the connector is inserted into the ends 5a, 6a of the shafts 5, 6 to replace the plug seal 21 with Oil is injected into the shafts 5 and 6 at high pressure through the internal passages 33 of the shafts 5 and 6. In particular, due to the spiral grooves 34 formed in the shafts 5 and 6, the oil leaving the internal passage 33 forms an oil film between the shafts 5 and 6 and the rotor 7. The spiral groove can "loosen" the rotor and then disassemble the rotor 7.

M: Motor 1: Vacuum pump 1a: Pumping stage 1b: Pumping stage 1c: Pumping stage 1d: pumping stage 1e: pumping stage 1f: Pumping stage 2: stator 2a: half shell 2b: half shell 2c: Seal support 2d: Bearing support frame 3: entrance 4: export 5: axis 5a: end 5b: end 6: axis 6a: end 7: Rotor 8a: First rotor element 8b: second rotor element 9: Wheel hub 10: Pressure chamber 11: Channel 12: oil tank 13: Rolling member 14: Lubricant sealing device 15: Central penetrating shell 16: petals 17: Expandable clamping ring 18a: Conical split ring 18b: Conical split ring 20: Nut 21: Plug seal 22: main body 23: O-ring seal 24: Axial rod 25: Groove 26: blind hole 27: Frame 28: Nose 29: Seal 30: Orifice 32: Conical central housing 33: internal channel 34: Spiral groove 35: rubbing ring 36: O-ring seal 37: ring groove 38: Seal 39: screw 40: fixed hole 41: O-ring seal 42: disc 43: horizontal wall 44: spiral groove 45: Flushing gas inlet 46: Fixing and sealing ring 47: O-ring seal 48: ring groove

Other features and advantages of the present invention will be derived from the following descriptions given by way of non-limiting examples and with reference to the accompanying drawings, in which:

[Figure 1] is a top partial cross-sectional view of a dry vacuum pump (shown as a plugless seal), where one rotor is offset from the other by 90˚.

[Fig. 2] is an exploded perspective view of components of the vacuum pump of Fig. 1. [Fig.

[Fig. 3] Shows several elements in Fig. 2 in an assembled state. In this drawing, only one of the two rotors is shown to facilitate the visualization of the rotor fixed on the shaft.

[Fig. 4a] is a perspective view of the expandable clamping ring of the vacuum pump of Fig. 1. [Fig.

[Fig. 4b] is a schematic diagram of the expandable clamping ring of Fig. 4a.

[Fig. 5] is a perspective view of the first embodiment of the seal ring of the vacuum pump of Fig. 1. [Fig.

[Fig. 6] is a perspective view of the first embodiment of the plug seal of the vacuum pump of Fig. 1. [Fig.

[Fig. 7] is a front view of the rotor of the vacuum pump of Fig. 1. [Fig.

[Fig. 8] is a plan view of the rotor of Fig. 7. [Fig.

[Fig. 9] A perspective view showing two rotors of the vacuum pump according to the second embodiment.

[Fig. 10] A perspective view showing a rotor of a vacuum pump according to a third embodiment.

[Fig. 11] A perspective view showing a rotor of a vacuum pump according to a fourth embodiment.

[Figure 12a] shows a longitudinal section element of a vacuum pump according to a variant embodiment.

[Fig. 12b] is a perspective view of the rubbing ring of Fig. 12a.

[Fig. 13a] A longitudinal section view showing an element of a vacuum pump with a seal according to a second embodiment.

[Fig. 13b] A perspective view showing the dynamic seal ring of the vacuum pump of Fig. 13a.

[Fig. 13c] A perspective view showing the complementary bearing surface of the dynamic seal ring arranged in the stator of the vacuum pump of Fig. 13a.

[Fig. 14a] A longitudinal section view showing the elements of the vacuum pump according to the third embodiment in which the seal mechanism is located between the rotor and the stator.

[Fig. 14b] A perspective view showing the fixing and sealing ring of the vacuum pump of Fig. 14a.

[Fig. 14c] A perspective view showing a rotor of the vacuum pump of Fig. 14a.

[Fig. 15a] A longitudinal section view showing an element of a vacuum pump with a plug seal according to the second embodiment.

[Fig. 15b] A partial perspective view showing elements of the vacuum pump of Fig. 15a.

[Fig. 15c] A perspective view showing the plug seal of the vacuum pump of Fig. 15a.

[Fig. 16] A schematic and partial view showing the engagement of a rotor and a shaft in a vacuum pump according to another embodiment.

In the above drawings, the same elements have the same reference numbers.

1: Vacuum pump

1a: Pumping stage

1b: Pumping stage

1c: Pumping stage

1d: pumping stage

1e: pumping stage

1f: Pumping stage

2: stator

2a: half shell

2c: Seal support

2d: Bearing support frame

3: entrance

4: export

5: axis

5a: end

6: axis

6a: end

7: Rotor

8a: First rotor element

8b: second rotor element

9: Wheel hub

10: Pressure chamber

11: Channel

12: oil tank

13: Rolling member

14: Lubricant sealing device

15: Central penetrating shell

17: Expandable clamping ring

28: Nose

29: Seal

M: Motor

Claims (21)

A rotor (7) for a multi-stage dry vacuum pump (1), the vacuum pump (1) includes two shafts (5, 6), the two shafts (5, 6) are configured to pump at least two The stages (1a-1f) rotate synchronously in opposite directions to drive the gas to be pumped between the inlet (3) and the outlet (4). The rotor (7) includes: The hub (9) is configured to engage on one of the plurality of shafts (5, 6) of the vacuum pump (1), and At least one first rotor element and one second rotor element (8a, 8b) are arranged along the hub (9), and each rotor element (8a, 8b) extends in the respective pumping stages (1a-1f) and It is configured to interlock with the respective rotor elements (8a, 8b) conjugated to the other rotor (7) of the vacuum pump (1), and the rotor elements (8a, 8b) and the hub (9) are made to be One-piece. The rotor (7) according to claim 1, wherein the hub (9) is characterized by having a nose (28) at an axial end of the rotor (7), and the nose (28) is located on the rotor element (8b), which is intended to be configured in the final pumping stage (1f) communicating with the outlet (4); and on the side of the driving part of the vacuum pump (1), the seal ( 29; 38) is intended to be arranged between the nose (28) of the rotor (7) and the stator (2) of the vacuum pump (1). The rotor (7) according to claim 1 or 2, wherein the at least one rotor element (8a, 8b) includes at least two lobes (16). The rotor (7) according to claim 3, wherein the lobe (16) is characterized by having a helical twist around the longitudinal axis. The rotor (7) according to claim 1 or 2, wherein the contours of the rotor elements (8a, 8b) are different, and the first rotor element (8a) is intended to be arranged at the inlet ( 3) The connected first pumping stage (1a) includes at least two lobes (16) characterized by a helical twist, and the at least one second rotor element (8b) includes at least two straight lobes ( 16). The rotor (7) according to claim 1 or 2, wherein the hub (9) has a central opening (15) passing through it, and the central opening (15) is configured to interact with the shaft (5, 6) When engaged, one end (5a, 6a) of the shaft (5, 6) is accommodated. The rotor (7) of claim 1 or 2, wherein the hub (9) is characterized by having a tapered central housing (32) configured to accommodate a complementary tapered shaft One of the ends (5a, 6a) of (5, 6) energizes the rotor (7) to drive into the shaft (5, 6). A multi-stage dry vacuum pump (1), including: Two shafts (5, 6), the two shafts (5, 6) are configured to rotate synchronously in opposite directions in at least two pumping stages (1a-1f) of the vacuum pump (1) for driving The gas to be pumped between the inlet (3) and the outlet (4), and The two rotors (7) according to any one of claims 1 to 7, which are detachable and meshed with respective shafts (5, 6) of the vacuum pump (1). The dry vacuum pump (1) according to claim 8, wherein the hub (9) is characterized by having a nose (28) at an axial end of the rotor (7), and the nose (28) is located on the rotor On one side of the element (8b), which is arranged in the final pumping stage (1f) communicating with the outlet (4); and on the side of the driving part of the vacuum pump (1), the vacuum pump (1) ) Further comprises at least one sealing element (29; 38), the sealing element (29; 38) is arranged between the nose (28) of the rotor (7) and the stator (2). The dry vacuum pump (1) according to claim 9, wherein the seal (38) includes a dynamic sealing ring, and the dynamic sealing ring is characterized by having a disc (42) disposed facing the transverse wall (43) of the stator (2) ), the vacuum pump (1) includes a flushing gas inlet (45) discharged between the transverse wall (43) and the disc (42). The dry vacuum pump (1) according to claim 9, wherein the sealing member (29) includes a rubbing ring seal, and the vacuum pump (1) includes the nose (28) and the rubbing member provided on the rotor (7) Rub the rubbing ring (35) between the ring seals. The dry vacuum pump (1) according to claim 8, wherein the dry vacuum pump (1) includes a fixing and sealing ring (46), and the fixing and sealing ring (46) is mounted on the shaft (5, 6) against the One axial end of the rotor (7) and located on the side of the rotor element (8b), the rotor element (8b) is intended to be arranged on the side of the drive part of the vacuum pump (1) The outlet (4) is connected to the final pumping stage (1f). The dry vacuum pump (1) according to claim 12, wherein the fixing and sealing ring (46) includes a disc, and the disc is disposed facing the transverse wall (43) of the stator (2), and the vacuum pump (1) includes a pair of A flushing gas inlet (45) is discharged on the nose of the fixing and sealing ring (46) between the transverse wall (43) and the disc. The dry vacuum pump (1) according to claim 12, wherein the dry vacuum pump (1) further comprises at least one rubbing ring seal (29), and the rubbing ring seal (29) is arranged on the fixing and sealing ring (46) and the stator (2). The dry vacuum pump (1) according to claim 11 or 14, wherein the orifice (30) is arranged in the rubbing ring seal for injecting flushing gas. The dry vacuum pump (1) according to any one of claims 8 to 14, wherein the shaft (5, 6) is cantilever mounted. The dry vacuum pump (1) according to claim 16, wherein the shafts (5, 6) are supported by bearings located on the side of the final pumping stage (1f), the final pumping stage (1f) and The outlet (4) on the side of the driving part of the vacuum pump (1) communicates. The dry vacuum pump (1) according to claim 16, wherein the hub (9) of the rotor (7) is a hollow penetrating hub, wherein the vacuum pump (1) includes a plug seal (21), and the plug seals The piece (21) is installed in the central penetrating shell (15) of the hub (9) of the rotor (7) and is configured to seal the central penetrating shell (15) in a sealing manner. The dry vacuum pump (1) according to claim 16, wherein the hub (9) of the rotor (7) is a hollow penetrating hub, wherein the vacuum pump (1) includes at least one expandable clamping ring (17), the The expandable clamping ring (17) is accommodated in the central penetrating housing (15) of the hub (9), and is arranged at one end (5a, 6a) of the shaft (5, 6) and the hub ( Between 9), the rotor (7) is fixed to the shaft (5, 6) through the double cone assembly. The dry vacuum pump (1) according to claim 16, wherein at least one end (5a, 6a) of the shaft (5, 6) is tapered, and due to the cone that is complementary to the hub (9) of the rotor (7) The rotor (7) is driven to the tapered end (5a, 6a) of the shaft (5, 6). The dry vacuum pump (1) according to any one of claims 8 to 14, wherein the shafts (5, 6) are each supported by at least two bearings located on either side of the pumping stage (1a-1e).

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