TW201837321A - Rotating machine and rotors for use therein - Google Patents

Abstract

A rotating machine and rotor are disclosed. The rotating machine comprises: a stator; a rotor rotatable about an axis of rotation within the stator; at least one fixed supporting member comprising a shaft passing through the rotor and supporting the two bearings, the two bearings being mounted around the at least one fixed supporting member; wherein the rotor is rotatably mounted on an outer surface of the two bearings, and the two bearings are located towards opposing axial ends of the rotor.

Description

Rotary machine and rotor for rotating machine

The invention relates to the field of rotary machines and rotors for rotary machines.

The present invention relates to the field of rotating machines, and in the preferred embodiment relates to pumps, and in particular to vacuum pumps. Rotating machines need to be carefully designed and manufactured to allow the moving parts to collide with each other precisely. For example, when the radial clearance is too small, the radial clearance can cause the moving parts of a rotating machine to get stuck, and when the radial clearance is too large, the radial clearance can lead to poor performance. It is increasingly desirable to make the pump smaller. The smaller a pump, the faster it must be rotated to pump the same amount of fluid for a given period of time. Faster rotation can result in poorer stability of the moving parts, which can cause problems with small gaps. In addition, the increased speed can also result in increased temperatures, which can be problematic due to uneven expansion of the assembly and due to increased wear. A conventional pump, such as the pump shown in FIG. 1, includes a rotor 20 located within a stator 10 that is mounted for rotation within the bearing 30. An increased rotational speed of one of the rotors can cause the rotor to flex, and this deflection can increase significantly as it approaches the resonant frequency of the rotor. It would be desirable to provide a rotating machine with an improved tolerance for increased speed and temperature.

A first aspect of the present invention provides a rotary machine comprising: a stator; a rotor rotatable about a rotation axis of the stator; the rotor rotatably mounted on two bearings, the two Bearings are positioned toward opposite axial ends of the rotor; at least one fixed support member supporting at least one of the bearings, the at least one of the bearings being mounted about the at least one fixed support member such that the rotor Rotatablely mounted on an outer surface of one of the at least one of the bearings; wherein the at least one fixed support member includes a shaft member that passes through the rotor, the two bearings being mounted for positioning toward either end of the rotor On the part of the shaft. The inventors of the present invention have recognized that the resonant frequency and stiffness of the rotor are related to the thickness or diameter of the shaft member on which the rotor is mounted; an increase in one of the thicknesses of the shaft member increases both the resonant frequency and the stiffness. However, the inventors have also recognized that an increased thickness of one of the shaft members requires an increased bearing size and this results in higher power consumption and increased heat generated in the rotating machine. The inventors have solved these conflicting problems in a simple and subtle manner by mounting the rotor on the outer surface of at least one of the bearings (rather than in a conventional manner, mounted within the inner surface of the bearing). In this way, bearings of the same size can support a substantially thicker and therefore stiffer shaft member. To achieve this, at least one of the bearings is mounted about a fixed support member and the rotor is mounted on the outer surface of the bearing to allow the rotor to be supported on the outer bearing diameter rather than the inner bearing diameter. In this way, an increased diameter rotor support can be used for bearings of the same size. The inner race of the bearing is supported by the fixed component and thus fixed, while the outer race supports the rotating rotor and moves. This is different from conventional bearings in which the outer race is fixed and the inner race moves with the rotating rotor shaft. The rotor is mounted towards either axial end to increase the resistance to lateral movement of the rotor. In this regard, the bearings are each positioned away from a central position such that in certain embodiments, the rotor does not extend beyond the bearings, or only extends beyond the bearings by a factor of less than 5% of the axial length of the rotor. . Furthermore, the fixed support member is fixed and non-rotatable and passes through one of the shaft members of the rotor. This provides a robust support for the rotor. It should be noted that, conventionally, bearing selection is typically driven by the shaft diameter due to rotor dynamics and the need for a certain minimum stiffness, and this can result in bearings having significantly higher load capacity than needed. By mounting the rotor on the outer surface of at least one of the bearings, the bearing selection can be driven more strongly by the load capacity of the bearing. It should be noted that the rotor can be mounted on one of the bearings facing either end of the rotor or on a plurality of bearings facing either axial end. The bearing can have several forms and, in some embodiments, can be a rolling element bearing mounted within a housing. In certain embodiments, the at least one fixed support member includes a cooling fluid inlet for cooling fluid flow, a cooling fluid flow path, and a cooling fluid outlet. A particularly advantageous feature of mounting the bearing on a stationary support and allowing the rotor to rotate about the bearing is that this provides a chance to provide a cooling fluid for the stationary support, thereby allowing the bearing and other potentially features of the rotating machine located adjacent thereto to be cooled. . Applying a cooling fluid to a fixed component is a simple matter, and applying a cooling fluid to a rotating component is much more complicated. Therefore, mounting the bearing on a stationary component rather than on the rotating shaft of the rotor provides an opportunity to apply cooling fluid to the stationary component. If the bearing is not allowed to become overheated, the bearing will preferably function and have a longer life. Overheating of the bearing can cause internal voids to change and cause the metal to become soft. In addition, the seal located near the bearing can also be cooled by the cooling fluid, which can also result in a longer life and also results in a more efficient seal. In this regard, it should be noted that the bearing generates significant heat during use and this heat can be dissipated by cooling the support members of the bearing. The cooling fluid can be any fluid that is capable of transporting heat away, but in some embodiments is water, the water has a high heat capacity and is inexpensive, non-toxic, and readily available. In certain embodiments, the fluid inlet and the fluid outlet are located at opposite axial ends of the shaft member. In other embodiments, the inlet and outlet are located at the same end for cooling the entire shaft member, or there is an inlet and an outlet at each end to independently cool each end of the shaft member. Having the fluid inlet and outlet at the opposite axial ends of the shaft allows cooling fluid to flow through the shaft and transfer heat along the entire length of the shaft, rather than only in the region of the bearing. This in turn provides a cooling effect to the rotor. In this regard, cooling the stator of a rotating machine is generally quite simple, and cooling the rotor that is sealed within the machine is more difficult. Mounting the rotor on a stationary shaft member and providing a cooling fluid to provide cooling to the rotor through the shaft member is an efficient and convenient way. In other embodiments, the inlet and outlet may be located at the same end, with a flow path continuing along the shaft member and rearwardly reaching the cooling fluid outlet at the same end as the inlet. In some embodiments, the shaft member has a central portion between the bearing mounting portions, one of the central portions having an outer circumference proximate to an inner circumference of the rotor. In the case where the shaft member passes through the rotor, the outer circumference of the central portion of the shaft member is close to the inner circumference of one of the rotors, thereby allowing the cooling of the shaft member to have a cooling effect on the rotor due to heat transfer between the corresponding surfaces. In this regard, the distance between the surfaces should be sufficiently large that any deflection of the rotor does not cause the surfaces to contact, while being sufficiently low to improve heat transfer. In this regard, a distance between 100 microns and 3 mm can be envisaged. In some embodiments, the central portion of the shaft member has a diameter that is larger than the bearing mounting portions. It may be advantageous to increase the diameter of the shaft member within the rotor that is remote from the bearing. In this regard, in the case of a support bearing, a narrower shaft member results in a smaller bearing and lower power requirements and less heating, whereas in the case where the shaft member is being cooled, a wider shaft member can result in an improvement. Heat transfer and a lower temperature rotor. Thus, in certain embodiments, it may be advantageous to increase the diameter of the shaft member at the central portion when compared to the portion in which the bearing is mounted. In some embodiments, the outer surface of the shaft member can be roughened such that heat transfer to the surface of the shaft member is improved. In this regard, increasing the surface area increases the heat transfer of the surface, but can also result in an increased distance from at least some of the surface to the rotor. This in turn will reduce the heat transfer between the rotor and the shaft member to some extent. Thus, providing small fins (such as a spiral pattern) on the outer surface of the shaft member can improve heat transfer and can be advantageous. In certain embodiments, the rotary machine includes at least one other rotor that is rotatable about at least one other rotational axis that is parallel to the rotational axis, each of the at least one other rotor being mounted to two In other bearings, at least one of the other bearings is mounted about at least one other fixed support member; wherein each of the at least one other rotor is rotatably mounted to the at least one of the two other bearings On one of the outer surfaces, the two other bearings are positioned toward opposite axial ends of the at least one other rotor. While embodiments of the present invention are applicable to single rotor machines, such embodiments are particularly applicable to multi-rotor machines (such as dual rotor machines) in which two or more rotors are rotated within a stator, and each The rotor system is mounted on a bearing on a fixed support member. In particular, such dual rotor machines or multi-rotor machines require small clearances and therefore high tolerances, and mount at least one end of the rotor on the outer surface of the bearing and thereby provide less deflection and greater stiffness. advantageous. In certain embodiments, the rotor, the stationary support member, and the bearings of the rotor correspond to at least one other rotor and have the same features. In certain embodiments, the rotor and the other rotor each include a radial projection and are mounted such that the radial projections engage one another. A plurality of dual-rotor machines or multi-rotor machines have intermeshing radial projections on their rotors, the intermeshing radial projections for pumping a fluid, and such types of rotary machines are particularly suitable for use in the present invention Example. In some embodiments, the rotary machine further includes a motor and a gear member driven by the motor for driving the rotor, the motor being biased relative to the rotor. The rotor can be driven by a motor and the motor can be biased relative to the rotor, wherein the gears are used to drive the rotor. In the case of a twin rotor machine, the gear will drive the two rotors. In other embodiments, the motor can be directly coupled to the rotor; and in the presence of a dual rotor, the gear can be used to drive the second rotor. In certain embodiments, the rotor includes an axial projection at a defined non-zero radial position on either end of the rotor, the axial projections forming a hollow cylindrical shape, the axial projections One of the inner circumferences is mounted on one of the outer circumferences of one of the bearings. In order to mount the motor on the outer surface of the bearing, the rotor can have axial projections at a particular radial position, the axial projections will have the form of a hollow cylinder and can be mounted around the bearing. These projections provide a mounting surface for supporting the rotor on the outer surface of the bearing. In some embodiments, the gear members are configured to contact the axial projections to drive the rotor. Where there are axial projections for mounting the rotor on the bearing, the axial projections can be driven by the gear member to rotate the rotor. In some embodiments, the bearings are mounted to the fixed support member as a tight clearance fit and the rotor is mounted to the bearings as a slight interference fit. In order to provide bearings in which the outer surface of the bearing supports the rotating member, the bearings are mounted as a tight clearance fit on the fixed inner support member and the outer rotor is mounted as a slight interference fit such that the outer rotor is freely rotatable advantageous. The tight clearance fit allows for axial movement of the bearing on the shaft due to thermal expansion. A slight interference fit ensures that the outer race rotates with the rotor. The term "slight" indicates a certain allowance for allowing thermal expansion. Although embodiments of the invention are applicable to a number of different rotating machines, such embodiments are particularly suitable for use in a vacuum pump in which the clearance is small and thus the flexibility of a rotor is advantageous, particularly in the rotor When rotating rapidly or under high temperature conditions. The vacuum pump can be one of several different types of pumps, such as a spiral (single-ended or double-ended) pump or a dry pump of a roots pump or blower, a turbo pump or a vane pump . In certain embodiments, the pump comprises one of: a double ended pump comprising one of the discharge outlets at both axial ends and a single ended pump having a discharge port at one axial end And a pump having an inlet on the opposite radial side. A double-ended pump can be advantageous because the double-ended pump helps manage the thermal load when compression occurs in both directions, and the mechanical load on the shaft member is equal in either direction and on both bearings. However, the heat associated with such a pump can be high and such pumps tend to be relatively expensive. Therefore, providing additional cooling facilities for the pumps and a stiffer mounting member can be advantageous and is worthwhile in this pump. A second aspect of the present invention provides a rotor for a pump including an axial projection at a defined non-zero radial position on both axial ends of the rotor, the axial projections Each of the portions forms a hollow cylindrical shape and is configured to rotatably mount the rotor via a bearing located within the hollow cylindrical shape, wherein the rotor includes a cylindrical shape through one of the centers of the rotor The hole allows a shaft member to pass through the rotor. The rotor including one of the hollow cylindrical mounting projections at each end adapted to be mounted on the outer surface of the bearing allows the bearing to be mounted on the stationary support and allows at least one projection of the support shaft that acts as the rotor to be mounted to the bearing One of the inner support surfaces of the shaft member (as is customary) is wide. The increased diameter of one of the support shafts of the rotor provides rigidity and stability and increases its resonant frequency. The rotor includes axial projections at both ends, the projections forming a hollow cylindrical shape and configured to rotatably mount the rotor via bearings located within the hollow cylindrical shape. The rotor is hollow and includes a cylindrical space through one of the centers of the rotor such that a shaft member can pass through the rotor. Where the rotor has a hollow center, a shaft member can pass through the center. This reduces the material required to make the rotor and reduces its weight. Moreover, where a cooling fluid is used, it provides a potential path for the cooling fluid to flow through the rotor and provide effective cooling along the length of the rotor. Other specific and preferred aspects are set forth in the accompanying independent technical solutions and the associated technical solutions. The features of the subsidiary technical solutions may be combined with the features of the independent technical solutions and combined with features other than those explicitly stated in the scope of the patent application. Where a device feature is illustrated as being operable to provide a function, it will be appreciated that this includes providing the functionality or adapting or configuring to provide one of the features of the device.

Before discussing the embodiments in more detail, an overview will first be provided. As previously noted, a small diameter shaft member on a rotating machine can provide a relatively low resonant frequency for a rotor that can compromise operating speed. As rotary machines such as pumps or compressors become smaller, rotary machines require higher operating speeds to move the same amount of fluid. As the speed increases, it is likely to approach the natural frequency of the rotor, which leads to instability. In particular, the deflection of the rotor results in a loss of the necessary clearance between the stationary part and the moving part. Any movement of the rotor is particularly detrimental to machines with small gaps. Increasing the diameter of the shaft member improves the stiffness of the shaft member and increases the natural frequency of the shaft member. However, increasing the diameter of the shaft member also increases the size of the bearing on which the shaft member is mounted, which results in the heat generated and One of the required power is increased. This has been solved by providing a rotor that is mounted on one of the outer surfaces of the bearing such that the outer race rotates with the rotor and the inner race is fixed. In this way, an increased mounting diameter of one of the rotors is provided without correspondingly increasing the size of the bearing. In order to provide a rotor that can be mounted in this manner, a rotor having a supporting stub or protrusion at either end is used, each of which has a hollow cylindrical shape. This rotor system is mounted on the outer surface of the bearing, and the cylindrical stub shaft surrounds the bearings and allows for rotation. One additional benefit of installing one of the rotors in this manner is that a cooling fluid can be used to cool the stationary support components, and thus the bearings and other access components (such as seals). In addition, providing a fixed support member as a shaft member extending through the rotor allows any cooling fluid to flow along the entire shaft member to have a cooling effect on the entire rotor. The rotor system within a rotating device (specifically, within a vacuum pump) is difficult to cool, and providing cooling in this manner can be advantageous. 2 shows a stator 10 having a water cooling 12 that surrounds two pump rotors 20 and 22 that are intermeshing with each other, and are themselves mounted to bearings 30. The pump rotors 20 and 22 are mounted via respective axial projections 21 and 23 having a hollow cylindrical shape and projecting from an outer axial edge of one of the pump rotors. These axial projections 21, 23 are supported on the outer surface of the bearing 30 and rotate about these bearings. The bearing 30 is mounted on a stationary shaft member 40 having a cooling fluid inlet 41 and an outlet 42. This cooling fluid allows the bearings to be cooled and helps protect the bearings from overheating. In this embodiment, there is a shaft seal 50 between the stator 10 and the bearing 30 that prevents or at least prevents oil surrounding the bearing from leaking into the pump body. In certain embodiments, to avoid an additional thermal load on the rotor, the shaft seal 50 can incorporate a piston ring rather than a lip seal. In other embodiments, the seal may be in the form of a mechanical face seal between the rotor and the top plate, rather than in the form of a radial lip seal on the outer side of the rotor. In this case, the top panel will have a shape that is slightly different than the top panel shown to allow for the installation of a mechanical face seal. Also shown in FIG. 2 is a gear 60 for driving the rotor via axial projections 21 and 23 to cause the rotor to rotate on the bearing 30. Thus, in this embodiment, the pump rotors 20, 22 are supported by a fixed water-cooled shaft member 40 via bearings 30. The inner surface of the bearing is mounted to the shaft member as a tight clearance fit, and the outer surface of the bearing has a slight interference fit with the rotor it supports. This enables the rotors 20, 22 and the axial projections 21, 23 to have a larger diameter than a conventional rotor shaft, since the bearings are located inside the support shaft rather than on the outer surface of the shaft (as in the prior art) The situation) (see Figure 1). The use of larger diameter shafts increases the natural frequency of the rotating block compared to a conventional assembly. It should be noted that for machines with two or more rotors, careful selection of materials will allow the thermal expansion of the top plate, rotor and stator to be matched so that the rotor and stator can be maintained under different operating conditions (which have different thermal load conditions). Radial gap between. For example, in some cases, the stator may be iron or steel and the housing is aluminum, and in this case care should be taken so that if the housing is maintained at 100 ° C and the stator is maintained at 200 ° C, then The shaft and stator bores will remain aligned with each other. In practice, the aluminum housing will also hold the oil used to lubricate the bearings and gears and will need to be maintained at around 80 °C as a maximum temperature. In Figure 2, a water cooled bearing support is used to cool the oil leaving the bearing. In this embodiment, the bearing has a slight interference fit in the rotor and a tight clearance fit on the bearing support. The bearing preload is applied to the inner race on the support shaft using a spring, which may be a wave spring or a coil spring. Figure 2 shows a double ended pump design designed to have a vent at both ends. This design helps manage the thermal load on the rotor and stator as well as the axial load on the bearings. As can be seen, the fixed bearing support member 40 is in the form of a shaft member in which the cooling fluid flows into an inlet 41 and exits from an outlet 42 at the opposite axial ends of the shaft member. In this way, the cooling fluid not only provides a cooling effect to the bearing, but also provides some degree of cooling to the rotor. The rotor is mounted to the bearing and shaped such that there is a narrow gap between the inner diameter of the main central body of the rotor and the stationary shaft member. This narrow gap allows for some degree of deflection of the rotor and/or shaft member without the rotor contacting the shaft member and jamming the pump while also providing heat transfer between the two bodies. Figure 3 shows a design of a Rouer blower with an inlet (not shown) at the top and bottom. The Rouge blower pump can significantly heat up during use, which can result in excessive bearing temperatures. Therefore, it is advantageous to provide additional cooling for the Rogowski blower pump. In this embodiment, as in the embodiment of Fig. 2, the bearing 30 is mounted on a through shaft member 40 which not only provides cooling for the bearing and the seal member 50 around the bearing, but also the rotor 20, 22 itself. Provides cooling. FIG. 4 shows a one-rotor blower pump driven by a biasing motor 70. The bias motor 70 drives the rotors 20, 22 of the pump via a gear 60. FIG. 5 shows an alternate embodiment in which the motor 70 is directly coupled to one of the rotors 22 and the gearing device is used to drive another rotor 20. One effect of this alternative embodiment is that the shaft member 40 that passes through the directly driven rotor 22 is extended and this results in the shaft member being less well supported with the possibility of greater deflection. Figure 6 shows a pump in which the shaft member 40 for mounting the bearing 30 has one of the diameters smaller than the one at its central portion around the bearing mounting portion. Providing an increased diameter at the central portion allows for increased heat capacity and fluid flow and increases the likelihood of heat transfer. Furthermore, the heat capacity of the cooled rotors 20, 22 is reduced by the increased internal diameter. In some embodiments, there are small fins on the outer surface of the shaft member 40 that improve the heat transfer of the outer surface. In this regard, the fins increase the surface area there, but should not be too large, which would therefore increase the distance between the rotor and the body of the shaft member. This particular embodiment is a double ended pump that is particularly suitable for this design due to its increased cost and high efficiency. While embodiments of the present invention are applicable to any type of rotating machine, the embodiments are particularly applicable to thermally operated semiconductor vacuum pumps in which the stator surface temperature typically exceeds 150 °C. Although the present invention has been described in detail with reference to the accompanying drawings, it is understood that the invention is not to be construed as Various changes and modifications can be made in the embodiments in the context of the scope of the invention as defined by the equivalents.

10‧‧‧ Stator

12‧‧‧Cooling/water cooling

20‧‧‧Rotor/Pump Rotor

21‧‧‧Rotor short shaft/axial projection

22‧‧‧Rotor/Pump Rotor

23‧‧‧Rotor short shaft/axial projection

30‧‧‧ Bearing

40‧‧‧Bearing support parts/fixed shaft parts/fixed water-cooled shaft parts/fixed bearing support parts/through shaft parts/shaft parts

41‧‧‧Cooling fluid inlet/inlet

42‧‧‧Cooling fluid outlet/export

50‧‧‧Axis seals/seals

60‧‧‧ gears

70‧‧‧Motor/Offset Motor

Embodiments of the present invention will now be further described with reference to the drawings in which: FIG. 1 shows a pump according to the prior art; FIG. 2 shows a pump according to an embodiment; FIG. 3 shows an embodiment according to an embodiment. One of the inlets has a Luis blower design at the top and bottom; FIG. 4 shows one of the Luer blower pumps driven by a biasing motor coupled to the pump by a gear according to an embodiment; FIG. 5 shows the drive as shown in FIG. One of the pumps shown in the pump directly couples the motor; and Figure 6 shows a pump having improved cooling due to an increased diameter support shaft member in accordance with an embodiment.

Claims (23)

A rotary machine comprising: a stator; a rotor rotatable about a rotational axis of the stator; the rotor being rotatably mounted to two bearings, the two bearings being oriented opposite the rotor Positioning; at least one fixed support member supporting the two bearings, the bearings being mounted about the at least one fixed support member such that the rotor is rotatably mounted outside of the at least one of the bearings The surface; wherein the at least one fixed support member includes a shaft member passing through the rotor, the two bearings being mounted on a portion of the shaft member positioned toward either end of the rotor. The rotary machine of claim 1, the at least one fixed support member comprising a cooling fluid inlet for cooling the fluid flow, a cooling fluid flow path, and a cooling fluid outlet. The rotary machine of claim 2, wherein the fluid inlet and the fluid outlet are at opposite axial ends of the shaft member. The rotary machine of claim 2, wherein the fluid inlet and the fluid outlet are at the same axial end of the shaft member. A rotary machine according to any one of claims 1 to 4, wherein the two bearings are mounted around the shaft member, and the rotor is rotatably mounted on an outer surface of one of the two bearings. A rotary machine according to any one of claims 1 to 4, wherein the shaft member has a central portion between the bearing mounting portions, an outer circumference of one of the central portions being close to an inner circumference of the rotor. A rotary machine according to claim 6, wherein the central portion of the shaft member has a diameter that is larger than the portion on which the bearings are mounted. A rotary machine according to any one of claims 1 to 4, comprising at least one other rotor rotatable about another axis of rotation parallel to one of the axes of rotation, each of the at least one other rotor Mounted on two other bearings, at least one of which is mounted about at least one other fixed support member; wherein each of the at least one other rotor is rotatably mounted to the two other On the outer surface of at least one of the bearings, the two other bearings are positioned toward opposite axial ends of the at least one other rotor. A rotary machine according to claim 8, wherein the other rotor, the at least one other fixed support member, and the two other bearings have features corresponding to the respective rotors, the at least one fixed support member, and the two bearings. A rotary machine according to claim 8, wherein the rotor and the other rotor each comprise a radial projection and are mounted such that the radial projections mesh with each other. A rotary machine according to any one of claims 1 to 4, further comprising a motor and a gear member driven by the motor for driving the rotor, the motor being biased relative to the rotor. The rotary machine of claim 11, when attached to any one of claims 8 to 10, wherein the motor is operable to drive the rotor and the other rotor via the gear member. A rotary machine according to any one of claims 1 to 4, further comprising a motor coupled directly to the rotor. A rotary machine according to claim 13 when attached to any one of claims 8 to 10 and further comprising a gear member driven by the motor, wherein the gear member is operable to drive the other rotor. A rotary machine according to any one of claims 1 to 4, wherein the rotor includes an axial projection at a defined non-zero radial position on either end of the rotor, the axial projections forming a hollow cylindrical shape The inner circumference of one of the axial projections is mounted on an outer circumference of one of the bearings. A rotary machine as claimed in claim 15, when attached to claim 12, 13 or 14, wherein the gear member is configured to contact the axial projections to drive the rotor. A rotary machine according to any one of claims 1 to 4, wherein the bearings are mounted to the fixed support member as a tight clearance fit, and the rotor is mounted to the bearings as a slight interference fit. A rotary machine according to any one of claims 1 to 4, wherein the rotary machine comprises a vacuum pump. A rotary machine according to claim 18, wherein the vacuum pump comprises one of: a screw pump or a dry pump of a Rouge pump or a blower, a turbo pump, or a vane pump. A rotary machine according to claim 18, wherein the pump comprises one of: a double-end pump including one of the discharge outlets at both axial ends, and a discharge port at one axial end The end pump, and one of the pumps having an inlet on the opposite radial side. A rotor for a pump, the rotor including axial projections at a defined non-zero radial position on both axial ends of the rotor, the axial projections each forming a hollow cylindrical shape, and The rotor is configured to be rotatably mounted via a bearing located within the shape of the hollow cylinder; wherein the rotor includes a cylindrical bore through a center of one of the rotors such that a shaft member can pass through the rotor. The rotor of claim 21, wherein the rotor includes the axial projections at a defined non-zero radial position at the two axial ends of the rotor, the axial projections forming a hollow cylindrical shape and The configuration is rotatably mounted to the rotor via bearings located within the hollow cylindrical shape. The rotor of any of claims 21 or 22, and further comprising a bearing mounted in each of the axial projections.