Pump, bearing assembly for a pump, and method for assembling a bearing assembly - Patents.com

Abstract

A bearing assembly (10), a method of assembling the bearing assembly, and a pump are disclosed. The bearing assembly is for mounting a rotatable shaft of a pump and includes an inner ring (14) and an outer ring (12) and a plurality of rollable elements (16) mounted between the inner and outer rings (14, 12). The bearing assembly includes a lubricating oil guide element (30) extending radially outward from an outer periphery of the inner ring (14). The lubricating oil guide element (30) may include an inclined radial surface. At least a portion of the inclined radial surface faces an annular gap between the inner and outer rings (14, 12), and a radially inner portion of the inclined surface is closer to the rollable elements (16) than a radially outer portion of the inclined surface.

Description

[Technical field]

[0001] The present invention relates to a bearing assembly for a pump, a method of assembling the bearing assembly, and a pump equipped with such a bearing assembly. [Background technology]

[0002] Pumps with oil-lubricated bearings are often restricted to limited operating orientations to allow the oil circuit to be maintained and isolated from the pump mechanism. Certain applications require additional operating orientations that cannot be accommodated with standard products. In this regard, in standard products, the pump is oriented with its axis of rotation vertical, with the oil-lubricated bearings located below the rotor. In an upside-down orientation, the oil-lubricated bearings are above the rotor, but in pumps configured to operate in any orientation, the pump's axis of rotation can be horizontal or at any angle between horizontal and vertical. To accommodate such orientations, a method is needed to distribute oil throughout the oil circuit regardless of the pump's orientation. This problem has been addressed through the use of oil flingers.

[0003] The oil flinger is mounted on the shaft of the pump and is positioned to impede oil migration along the shaft and direct oil away from the shaft. Locating the flinger on the shaft presents some assembly challenges and can lead to imbalances in the rotor dynamics of the pump, requiring rebalancing when the flinger is replaced. Summary of the Invention [Means for solving the problem]

[0004] A first aspect provides a bearing assembly for mounting a rotatable shaft of a pump, the bearing assembly comprising: a bearing including an inner ring and an outer ring and a plurality of rollable elements mounted between the inner ring and the outer ring; and a lubricating oil guiding element extending radially outwardly from an outer periphery of the inner ring, the lubricating oil guiding element including a radially extending surface, at least a portion of the radially extending surface facing an annular gap between the inner ring and the outer ring.

[0005] The lubricating oil guide element or oil flinger extending radially from the inner ring portion of the bearing assembly allows the element to rotate and provide the flinging action without being directly attached to the shaft. This configuration allows any balancing required by the presence of the lubricating oil guide element to be performed on the bearing assembly before the bearing assembly is mounted on the pump. Also, the lubricating oil guide element can be mounted on the pump together with the bearing assembly, avoiding the need for an additional mounting step. Furthermore, if the lubricating oil guide element needs to be replaced, it can be replaced together with the bearing assembly. This allows the oil flinger to be replaced without modifying the pump. Furthermore, providing such a new bearing assembly on a conventional pump allows the pump to be retrofitted with an oil flinger.

[0006] The lubricating oil guiding element is arranged with a radially extending surface that extends at least partially across the annular gap between the inner and outer rings, which annular gap confines the rollable elements so that lubricating oil, such as oil, flowing through the gap contacts the lubricating oil guiding element and is guided away from the shaft supported by the bearing assembly. This arrangement allows the lubricating oil to be guided away from the shaft both when the pump is operating and the lubricating oil guiding element is rotating, and when the pump is not operating and the element is stationary.

[0007] In some embodiments, the radially extending surface facing the rollable element is an inclined surface, a radially inner portion of the radially extending surface being closer to the rollable element than a radially outer portion of the radially extending surface.

[0008] The inclined or angled surfaces help guide the lubricating oil away from the bearings, which can be particularly advantageous when the pump is not running and there is no centrifugal force acting on the lubricating oil contacting the surfaces.

[0009] In some embodiments, the lubricating oil guide element is disposed towards an axial end of the inner race.

[0010] In some embodiments, the lubricating oil guide element includes a drip edge on a surface facing away from the rollable element.

[0011] One potential problem that may arise, especially when the pump is stationary, is that oil or lubricating oil that adheres to the lubricating oil guiding element due to surface tension may run down the radially outer surface and then along the surface facing away from the bearing towards the shaft. In some embodiments, such flow is prevented by providing a dripping edge on the surface facing away from the bearing. The dripping edge prevents the flow such that the lubricating oil collects at this point and forms a droplet, which falls off the surface. The dripping edge may be an angled surface, some form of relief, a lip or a recess.

[0012] In some embodiments, the surface facing away from the rollable element comprises an annular recess, an edge of the annular recess constituting the drip edge.

[0013] The annular recess or groove in the surface of the lubricating oil guiding element facing away from the bearing provides a dripping edge for the oil or lubricating oil that adheres to the lubricating oil guiding element by surface tension and moves along this surface, which is particularly effective when the pump is not running and the lubricating oil or oil is not thrown off the lubricating oil guiding element by rotational forces.

[0014] In some embodiments, the annular recess has a radially inner edge, the annular recess being between 30 and 70% of the distance between the radially inner edge and the radially outer edge of the surface facing away from the rollable element.

[0015] The drip edge, which in some embodiments is the inner edge of the recess or groove, may be advantageously located at a distance from the shaft such that when the bearing is mounted on the shaft, the lubricating oil does not approach the shaft before dripping off the surface. If the drip edge is at a distance from the inner radius of the inner ring, when the bearing is mounted on the pump, the pump housing may extend beyond the drip edge, in some embodiments to the inner edge of the recess, such that the lubricating oil drips onto the housing and is prevented from flowing between the housing and the shaft.

[0016] In some embodiments, a radially extending surface of the lubricating oil guiding element furthest from the rollable elements is flush with a radially extending surface of the inner ring furthest from the rollable elements or extends axially beyond a radially extending surface of the inner ring furthest from the rollable elements.

[0017] It may be advantageous if the lubricating oil guide element is flush with or extends slightly beyond the axial end of the inner ring of the bearing. In this regard, having the bearing flush with or extend slightly beyond the end of the inner ring when mounting the bearing in the pump can help position the bearing assembly on the shaft when the bearing assembly is mounted in a recess in the shaft. If the lubricating oil guide element is made of a material that is softer than the inner ring of the bearing assembly, such as a polymer, having the lubricating oil guide element extend slightly beyond the inner ring can help pinch and clamp the bearing assembly in place.

[0018] In some embodiments, a portion of the inner ring includes a thinned portion having a reduced outer diameter at a portion where the lubricating oil guide element is attached.

[0019] The oil guide element may be mounted on a reduced profile thin section of the inner ring to provide an axial backstop function that helps resist excessive movement within the bearing, and therefore the rotor, in the unlikely event of a bearing failure, thereby preventing or at least limiting collisions and subsequent damage to the rotating machinery.

[0020] In some embodiments, the lubricating oil guide element is integral with the inner race.

[0021] Integrating the lubricating oil guiding element into the inner ring also makes it easier to manufacture and provides a robust solution.

[0022] In another embodiment, the lubricating oil guiding element has an annular shape and is attached to the inner ring.

[0023] Alternatively, the lubricating oil guide element may be a separate element attached or coupled to the inner ring, which may facilitate easier assembly of the bearing, especially when bearing supports such as compact metal spring dampers are used.

[0024] The lubricating oil guide element can be attached to the inner ring in a number of ways, which can include at least one of a press fit, a clearance fit, an interference fit, bonding, crimping, circlips, or adhesive.

[0025] In some embodiments, the lubricating oil guide element is formed from one of a polymer, a composite, or a metal.

[0026] In some embodiments, the inner ring has an axial extension extending axially beyond the outer ring, the lubricating oil guide element being attached to the axial extension, the bearing assembly further comprises a bearing support configured to support the outer ring of the bearing, the bearing support having a radial extension surrounding at least a portion of an outer surface of the outer ring and extending across one end face of the outer ring towards the axial extension of the inner ring, thereby obscuring at least a portion of the annular gap between the inner ring and the outer ring, and the lubricating oil guide element being located further from the rollable element than the radial extension of the bearing support.

[0027] The bearing assembly may be constructed integrally with a bearing support. Advantageously, the bearing support may include a shield extending radially across the annular gap between the inner and outer rings, which shield may be configured to help provide some degree of lubricant retention and to provide robust axial and / or radial end stop protection. Having the shield extending from the bearing support, rather than from one of the inner and outer rings, facilitates manufacturing and assembly of the bearing assembly.

[0028] Although the bearing support may provide some degree of lubricating oil retention, when used in pumps configured to operate in different orientations it is important that there is at least one path for lubricating oil to exit the bearing, and thus in some embodiments the radial extension of the bearing support comprises a number of openings configured to allow the passage of lubricating oil between the interior of the bearing and the exterior of the bearing.

[0029] As mentioned above, for the bearing assembly to function when the pump is positioned in different orientations, passages for the lubricating oil to exit the bearing are advantageous. In some embodiments, these are provided by openings in the bearing support. The number of openings can be selected to provide an appropriate strength of the bearing support, such that it allows sufficient passage of the lubricating oil when the pump is positioned in different orientations, while providing robust axial and / or radial end stop protection.

[0030] In some embodiments, the plurality of apertures comprises at least three apertures, preferably at least nine apertures.

[0031] It has been found that three or four or more openings are sufficient to reduce accumulation of lubricating oil in the bearings, even when the pump is oriented horizontally, although nine openings have been found to be particularly advantageous.

[0032] In some embodiments, the lubricating oil guide element is configured to extend radially beyond at least a radially inner portion of the plurality of openings.

[0033] In order for the lubricating oil guiding element to enable effective guiding of the lubricating oil, it may be advantageous for the lubricating oil guiding element to extend beyond the radially inner portion of said opening.

[0034] In some embodiments, the axially extending portion of the inner ring includes a recess having a reduced outer diameter, and the radially extending portion of the bearing support extends into the recess.

[0035] In some embodiments, an innermost surface of the radially extending portion of the bearing support forms a side of a gap with the reduced profile outer surface of the inner ring.

[0036] The radial extension of the bearing support is configured to provide at least one of an axial and radial end stop in the event of bearing failure. The lubricating oil guiding element can provide a further axial end stop.

[0037] In some embodiments, the bearing support may be a compact spring metal damper.

[0038] In some embodiments, the outer diameter of the inner ring at the portion where the lubricating oil guide element is attached is smaller than the outer diameter of the recess in which the bearing support extends.

[0039] Positioning the lubricating oil guide element in a portion of the outer ring having a smaller diameter than the recess through which the bearing support extends allows the lubricating oil guide element to provide an additional axial end stop and also aids in positioning the different elements both when assembling the bearing assembly and when mounting it on the pump shaft.

[0040] A second aspect provides a pump including at least one rotatable shaft supporting a rotor within a stator, said at least one rotatable shaft being mounted on at least one bearing assembly according to the first aspect.

[0041] In some embodiments, the pump comprises a lubricating oil reservoir on one axial side of the bearing assembly and a lubricating oil recovery mechanism on the other axial side, the lubricating oil guide element is configured to guide lubricating oil onto the lubricating oil recovery mechanism, and the pump further comprises a lubricating oil transfer mechanism for transferring the lubricating oil from the lubricating oil recovery mechanism to the lubricating oil reservoir.

[0042] The lubricating oil used to lubricate the bearings can be recirculated using a lubricating oil recovery mechanism and a lubricating oil transfer mechanism, where the lubricating oil guide element guides the lubricating oil to the lubricating oil recovery mechanism, and the lubricating oil transfer mechanism transfers the lubricating oil from the recovery mechanism to a lubricating oil reservoir, where the lubricating oil is reused to lubricate the pump. The recovery and transfer mechanism, and of course the reservoir, can be a felt or fibrous material with storage and wicking functions. The recovery and recirculation of the lubricating oil helps to maintain a sufficient amount of lubricating oil in the system, preventing intermittent bearing lubrication and bearing damage.

[0043] In some embodiments, the pump comprises a vacuum pump, and in some embodiments, a turbomolecular pump.

[0044] In some embodiments, the pump includes a vacuum pump configured to operate in multiple orientations.

[0045] In vacuum pumps, it is important to prevent the lubricating oil used to lubricate the bearings from leaking into the pump chamber and contaminating the vacuum. Thus, the embodiments are particularly applicable to vacuum pumps, where the lubricating oil guiding element helps to protect the pump chamber from the ingress of lubricating oil.

[0046] Vacuum pumps that are configured to operate in multiple orientations, and that may in fact be transported and stored in multiple orientations, are at high risk of oil leakage and therefore the lubricating oil guide elements of the embodiments are particularly useful in such vacuum pumps.

[0047] A third aspect provides a method of assembling a bearing assembly according to the first aspect, the method comprising the steps of assembling the bearing by mounting rollable elements inside the inner and outer rings, and mounting a lubricating oil guiding element having an annular shape to the inner ring of the bearing, such that the lubricating oil guiding element extends radially outwardly from an outer periphery of the inner ring.

[0048] In some embodiments, the inner ring comprises an axial extension extending axially beyond the outer ring, and the method comprises a step performed prior to the step of attaching the lubricating oil guiding element, namely, attaching a bearing support to the outer ring of the bearing, the bearing support comprising a radial extension extending across one end face of the outer ring towards the axial extension of the inner ring, thereby obscuring at least a portion of the annular gap between the inner ring and the outer ring, and then performing the step of attaching the lubricating oil guiding element, the lubricating oil guiding element being attached at a position axially further from the rollable element than the radial extension of the bearing support, such that at least a portion of the radial extension of the bearing support is between the rollable element and the lubricating oil guiding element.

[0049] The bearing assembly assembled according to the above method is assembled such that the lubricating oil guide element is part of the bearing assembly. In some embodiments, the bearing support is also part of the assembly and is in place before being installed in the pump. This allows the bearing assembly to be balanced, cleaned, inspected and tested before being installed in the pump. The bearing assembly can be installed in the pump at the time of manufacture of the pump or at the time of service when the bearings are replaced.

[0050] Further particular and preferred aspects are set out in the independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate and in combinations other than those explicitly set out in the claims.

[0051] Where features of an apparatus are described as operable to provide a certain functionality, this should be understood to include features of the apparatus that provide that functionality or that are adapted or configured to provide that functionality.

[0052] Embodiments of the invention are further described below with reference to the accompanying drawings. [Brief description of the drawings]

[0053] [Figure 1] 1 illustrates a bearing assembly with an integrated oil flinger according to one embodiment. [Diagram 2] Schematic showing leakage of lubricating oil when the pump is placed upside down and there is no oil flinger [Diagram 3] 3 shows a schematic of how the lubricating oil flow changes when an oil flinger is added to the pump of FIG. 2; [Figure 4] 1 illustrates diagrammatically how an oil flinger can function as an axial backstop. [Diagram 5] This figure shows how oil accumulates when a bearing support without lubricating oil passages is used and the pump is operated in an upside down position. [Figure 6] 1 shows the lubricating oil recovery and transfer mechanism. [Figure 7] 1 presents a flow diagram illustrating steps in a method for assembling a bearing assembly according to one embodiment. [Figure 8] 1 illustrates a schematic of a bearing assembly with an integral oil flinger according to one embodiment. [Figure 9] 2 illustrates diagrammatically a further bearing assembly according to an embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Before describing the embodiments in detail, an overview will first be provided.

[0055] A bearing assembly having an integrated lubricating oil guide element or oil flinger is disclosed. Providing a bearing assembly with an oil flinger potentially offers several advantages. These include providing an axial backstop, protection from lubricating oil reaching the shaft, directing the lubricating oil towards a desired lubricating oil transport path, the ability to select an appropriate material for the flinger that may be dissimilar to that of the bearing, retrofitting an oil flinger to a pump when installing a new bearing assembly, and improved quality and vibration characteristics since the bearing assembly can be tested prior to assembly into the pump.

[0056] When using a bearing support having a bearing shield, such as the compact metal spring damper disclosed in GB 2019823, the entire disclosure of which is incorporated herein, an oil drain hole can be provided in the shield portion of the bearing support.

[0057] Any existing bearing arrangement in any orientation may use an oil flinger, which distributes oil passing through the bearings away from the pump shaft and prevents oil transmission to the pump mechanism. Traditionally, the flinger is a separate component that is attached to the pump shaft before adding the bearing assembly. This requires modification of the shaft and makes the oil flinger difficult to replace during maintenance. Due to the bearing design and location of the oil flinger inside the pump, it is also difficult to know if the assembly is correct because the bearings block the view. An incorrect assembly can cause oil transmission and vibration generation, both of which can be difficult to observe and find before the product is shipped for use.

[0058] At least some of these problems have been addressed by incorporating a lubricating oil guide element or oil flinger within the bearing assembly.

[0059] FIG. 1 shows a bearing assembly 10 with an integrated oil flinger 30. In this embodiment, the oil flinger 30 is a separate part that helps simplify assembly of the bearing assembly components 10. The bearing assembly 10 includes an outer race or ring 12, a cage 13 for holding rolling elements or balls 16, and an inner race or ring 14. The inner race 14 is configured to be mounted on the shaft of the pump and rotate therewith. The inner race 14 has an oil flinger 30 mounted on the outer surface of the shaft end. The bearing assembly is supported in a bearing support 20, which in this embodiment is a compact metal spring damper CMSD. The bearing support 20 includes a shield 26 that is integral with the bearing support 20 and allows some protection against oil loss from the bearing to the pump. In this embodiment, the shield 26 includes at least one opening 25 to allow some loss of oil from the bearing, which is necessary to inhibit pooling of oil in the bearing when the pump is operated in an inverted or horizontal position. There is a gap between the radially inner wall of the shield 26 and the outer wall of the inner ring 14. In this embodiment, the shield 26 spans a recess in the outer surface of the inner ring 14 such that there is an axial and radial clearance between the inner ring and the shield 26. In the event of bearing failure, axial and radial movement will be limited by the size of these gaps, so this bearing can provide both an axial and radial backup bearing for the pump in at least one direction.

[0060] The oil flinger 30 is mounted in a further recess in the axial end of the inner ring to provide an additional axial stop. In embodiments where the bearing is not mounted on a support with a shield 26, the oil flinger 30 can provide an axial stop on its own.

[0061] In this embodiment, the oil flinger 30 is attached to the inner race 14 once the bearing is inserted into the support 20. Once attached to the bearing assembly 10, the oil flinger 30 and bearing assembly can be tested together before being incorporated into the product, which can be done at the bearing manufacturer, ensuring that high quality components are shipped ready for assembly.

[0062] Testing the complete assembly with an integrated oil flinger provides greater assurance that the quality of the part is maintained after the flinger is installed. If an interference fit is used to control the radial position of the flinger, flash or debris can be generated as the part is pressed against the inner race. It may be possible to clean the assembly after the bearings are installed to remove any debris that may have been generated prior to testing. This may not be possible if the assembly is made at the pump production facility.

[0063] The material used to make the flinger will dictate the interference fit required in the bearing to manage the component under all operating conditions and rotational speeds, or the flinger can be attached to the bearing assembly in other ways, such as by adhesive bonding, crimping, circlips, etc.

[0064] Assembling the flinger and having the manufacturer perform subsequent bearing testing ensures that product quality is maintained.

[0065] Incorporating the oil flinger into the bearing assembly allows a new assembly to be retrofitted to an existing or older product in the field. This would not be possible if the flinger were mounted on the pump shaft as this would require an appropriately sized journal on the shaft onto which the flinger would press.

[0066] The addition of an oil flinger to the assembly prevents or at least inhibits direct transfer of oil if the pump is oriented upside down.

[0067] FIG. 2 shows the path of the lubricating oil without the oil flinger and how it flows along the shaft 67 towards the pump chamber, while FIG. 3 shows how the addition of the oil flinger 30 diverts the oil away from the shaft 67 and away from the pump chamber.

[0068] Pumps having bearing assemblies with oil flingers are beneficial because the flinger helps inhibit oil migration from the bearings to the pump mechanism, including during storage or transport. If the pump is turned upside down, the flinger prevents direct oil transfer. With standard bearings, oil can leak past the bearing shield and along the shaft into the motor area, where the oil can migrate into the pump mechanism or out the pump exhaust, either way reducing the supply of lubricating oil to lubricate the bearings and potentially leading to bearing failure. Bearing assemblies with integrated flingers provide a cover over the shaft area, reducing the risk of oil transfer and keeping the oil within the proper area of ​​the pump.

[0069] Fitting the bearing assembly with a flinger can help contain gas transport to the bearing area during operation and help reduce contamination of the oil by pump gases.

[0070] In traditional designs where the flinger is attached to the shaft, if the flinger is dislodged it would be very difficult to detect during manufacturing and may go unnoticed until the pump begins to lose oil during operation, leading to product reliability issues.

[0071] With the flinger integrated into the bearing assembly this provides a poke yoke solution to ensure it is not forgotten when assembling the pump and can be easily checked prior to assembly to the pump or during servicing.

[0072] As mentioned above, the addition of a flinger to the bearing assembly also provides a radial stop 51 for the bearing. Figure 4 shows a schematic cross section through one side of the bearing with the rotor shaft on the right side of the figure, and shows how the shield 26 of the bearing support 20 provides an axial end stop 50 and a radial end stop 52 for the bearing. The oil flinger 30 provides a further axial stop 51. This allows the bearing assembly to control excessive movement within the pump, and also provides a safety mechanism in the unlikely event of a bearing failure. This is particularly useful when retrofitting bearings to a conventional product, as it provides additional safety and robustness without any other modifications to the pump.

[0073] In this embodiment, the oil flinger 30 is shown below the CMSD shoulder or shield 26, and it is the inner portion of the flinger that forms the backstop, but it should be noted that the axial backstop could be provided by any portion of the flinger. However, the inner portion provides a particularly effective backstop due to its stiffness. The inner portion has a lower surface speed than the outer portion and contacts stationary surfaces, resulting in a lower relative surface speed. The inner portion has a lower surface speed than the outer portion and contacts stationary surfaces, resulting in a lower relative surface speed. Furthermore, it is the thicker portion of the flinger that contacts, which is compressed between the CMSD shoulders, and is therefore more effective at resisting movement. If the tip of the flinger were to act as a backstop, it would be left unsupported on one side and more susceptible to deformation.

[0074] The material selected for the flinger will affect its operation as an axial backstop, with suitably robust materials such as polymers, composites, metals, etc. being advantageous.

[0075] In conventional pump designs of any orientation, an oil flinger is mounted on the pump shaft and when the pump is serviced, the oil flinger must be replaced to prevent excessive creep or deterioration from the pumped media. Removal and re-installation of the flinger can upset the vibration and rotor dynamics of the product and ultimately requires balancing of the pump to ensure smooth operation after service.

[0076] Adding an oil flinger to the bearing assembly or providing a bearing assembly in which the oil flinger is integrated into the inner ring of the bearing mitigates these issues as the bearings have already been tested during manufacture, reducing the likelihood of pump vibration or rotor dynamics problems occurring after field maintenance.

[0077] The removal and subsequent fitting of a conventional oil flinger can be particularly difficult, requiring special tooling to ensure it is positioned correctly and to ensure the generation of debris / contaminants is minimised during operation. Providing a flinger on the bearing assembly can reduce these risks.

[0078] The oil flinger of the embodiment is configured to provide an oil recirculation path along with an oil collection and transfer mechanism. In this regard, oil entering the bearing assembly needs to be allowed to exit to prevent accumulation and strong drag. When pumped vertically (upright) and somewhat horizontally, oil enters and exits the bearing assembly from the bottom. When allowed to run inverted, the oil will attempt to fall by gravity and accumulate near the ball (see left diagram in FIG. 5). The oil relief hole 25 shown in the right diagram will allow oil to flow past the bearing and up the flinger (which may be rotating or stationary depending on pump operation) and from there to the recirculation felt system.

[0079] The number, location, size and shape of the holes will affect the oil level in the bearing and the flow rate through the bearing, and will also affect the strength of the shield 26. The location and orientation of the pump will also affect oil buildup. For example, if the pump is mounted horizontally, it is important to have a sufficient number of drain holes, with one toward the bottom. At least three holes have been found to work well, with nine holes being preferred. In this regard, the more holes there are, the more freedom there is in the orientation in which the bearing assembly can be mounted.

[0080] Figure 6 shows the oil recirculation path provided in the pump when it is oriented upside down, i.e., the bearing 10 supporting the rotor shaft 67 is positioned vertically above the motor and pump mechanism, according to one embodiment. The bearing assembly 10 is in a pump housing 68 and has an oil flinger 30 that prevents oil from flowing down the shaft towards the motor and directs the oil towards a recovery mechanism 60 where it can be recirculated and reused to lubricate the bearings. Oil is wicked from the recovery mechanism 60 by an oil transfer mechanism 62, which is a felt, towards an oil reservoir 64. There is an oil delivery means 66 that directs oil from the reservoir 64 towards the bearings.

[0081] Figure 7 shows a schematic of a method for assembling a bearing according to one embodiment. In a first step S10, the bearing is formed by mounting rollable elements, such as balls, within an inner and outer race, allowing the inner and outer races to rotate relative to each other.

[0082] In some embodiments, an additional step S20 is performed of mounting a bearing support to the outer ring of the bearing. In some cases, the bearing support has a shield extending radially across the annular gap between the inner and outer rings.

[0083] In the next step S30, a lubricating oil guide element is attached to the inner ring of the bearing so as to extend at least partially across the annular gap between the inner and outer rings, and, if there is a bearing support, the lubricating oil guide element is attached axially beyond the shield of the bearing support so as to be further away from the rolling elements than the shield.

[0084] Then there is the additional step S40 where the bearing assembly is cleaned, inspected and tested prior to installation in the pump.

[0085] FIG. 8 shows a further embodiment of the bearing assembly in which the oil flinger 30 is integral with the bearing inner ring 14. Integrating the oil flinger with the bearing inner ring makes the bearing easier to manufacture and provides a robust solution. In this embodiment, the surface of the bearing inner ring 14 facing away from the bearing (which in this orientation is the underside of the bearing) is provided with an annular recess or groove 32. This groove or recess 32 serves as a drip edge for the oil that flows down the deflector and along the underside when the rotor is not rotating. This annular recess 32 is arranged such that its radially inner edge radially exceeds the gap 69 between the rotor shaft 67 and the pump housing 68, so that any oil or lubricant that drips from this recess, for example when the rotor stops rotating, falls onto the pump housing part 68, rather than moving along the surface of the inner ring towards the shaft and falling into the gap between the housing and the shaft and flowing along the shaft towards the pump chamber.

[0086] The arrows in the figure represent the flow of oil when the pump is operating. The width of each race can be different sizes and is generally configured to fit snugly within the pump housing 68. The oil flinger or deflector 30 is configured to extend across the gap 69 between the pump housing 68 and the rotor shaft 67 and, as mentioned above, the groove or recess 32 presents a dripping edge to prevent oil leaking along the surface facing away from the bearing and onto the shaft when the rotor is at rest.

[0087] In this embodiment, the oil flinger 30 has a tapered or umbrella shape, with the radius of the oil flinger increasing away from the bearing.

[0088] Figure 9 shows an alternative embodiment in which the oil flinger and bearing inner shaft are formed as a single piece. In this embodiment, the surface of the oil flinger facing away from the bearing does not have a recess, but rather has an angled lower end face which itself forms a dripping edge. In this embodiment, the shape of the flinger or deflector 30 is not tapered, but is still angled away from the shaft so that the radius of the deflector away from the bearing is larger than the radius closer to the bearing, so that lubricating oil flowing along the deflector is deflected away from the shaft.

[0089] Although exemplary embodiments of the present invention are disclosed in detail herein with reference to the accompanying drawings, it should be understood that the present invention is not limited to the precise embodiments, and various changes and modifications may result by those skilled in the art without departing from the scope of the present invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0090] 10 Bearing assembly 12 Outer ring 13 Bearing cage 14 Inner Circle 16 Rollable elements 20 Bearing support 25 Aperture 26 Shield 30 Lubricating oil guide element / oil flinger 32 Recess 50, 51 Axial stop 52 Radial Stop 60 Oil recovery mechanism 62 Oil transfer mechanism 64 Oil Reservoir 66 Oil delivery means 67 Rotor shaft 68 Pump housing 69 Clearance between shaft and housing

Claims

1. 1. A bearing assembly for mounting a rotatable shaft of a pump, comprising: a bearing including an inner ring and an outer ring and a plurality of rollable elements mounted between the inner ring and the outer ring; a lubricant oil guiding element extending radially outward from an outer periphery of the inner ring, the lubricant oil guiding element having a radially extending surface, at least a portion of the radially extending surface facing an annular gap between the inner ring and the outer ring; and A bearing assembly comprising:

2. The bearing assembly of claim 1 , wherein the radially extending surfaces are inclined, a radially inner portion of the inclined surfaces being closer to the rollable elements than a radially outer portion of the inclined surfaces.

3. 3. A bearing assembly as claimed in claim 1 or 2, wherein the lubricating oil guide element is disposed towards one end of the inner ring.

4. A bearing assembly according to claim 1 , wherein the lubricating oil guiding element is provided with a dripping edge on a surface facing away from the rollable element.

5. 5. A bearing assembly according to claim 4, wherein said surface facing away from said rollable element comprises an annular recess, an edge of said annular recess constituting said drip edge.

6. 6. A bearing assembly according to claim 4 or 5, wherein the drip edge is between 30 and 70% of the distance between the radially inner and outer edges of the surface facing away from the rollable elements.

7. 7. A bearing assembly as claimed in any preceding claim, wherein a radially extending surface of the lubricating oil guiding element furthest from the rollable element is flush with a radially extending surface of the inner ring furthest from the rollable element or extends axially beyond a radially extending surface of the inner ring furthest from the rollable element.

8. A bearing assembly according to any preceding claim, wherein the lubricating oil guiding element is integral with the inner ring.

9. 8. A bearing assembly according to claim 1, wherein the lubricating oil guide element has an annular shape and is attached to the inner ring.

10. 10. The bearing assembly of claim 9, wherein a portion of the inner ring includes a thinned portion having a reduced outer diameter at a portion where the lubricating oil guide element is attached.

11. The bearing assembly of claim 10 , wherein the lubricating oil guide element is attached to the inner ring by at least one of a press fit, a clearance fit, an interference fit, a bond, a crimp, a circlip, or an adhesive.

12. The inner ring includes an axial extension extending axially beyond the outer ring, and the lubricating oil guide element is attached to the axial extension; The bearing assembly includes: a bearing support configured to support the outer ring of the bearing; Further equipped with the bearing support comprises a radial extension surrounding at least a portion of an outer surface of the outer ring and extending across one end face of the outer ring towards the axial extension of the inner ring, thereby obscuring at least a portion of the annular gap between the inner ring and the outer ring; A bearing assembly according to any one of claims 9 to 11, wherein the lubricating oil guide element is located further from the rollable element than the radial extension of the bearing support.

13. The bearing assembly of claim 12 , wherein the radial extension of the bearing support includes a plurality of openings configured to allow passage of lubricating oil between an interior of the bearing and an exterior of the bearing.

14. The bearing assembly of claim 13, wherein the plurality of apertures includes at least three apertures, preferably nine apertures.

15. 15. A bearing assembly according to claim 13 or 14, wherein the lubricating oil guide element is configured to extend radially beyond at least a radially inner portion of the plurality of openings.

16. 16. A bearing assembly as claimed in any one of claims 12 to 15, wherein the axially extending portion of the inner ring includes a recess having a reduced outer diameter, and the radially extending portion of the bearing support extends into the recess.

17. 17. The bearing assembly of claim 16, wherein an innermost surface of the radially extending portion of the bearing support forms one side of a gap between the inner surface of the reduced outer diameter recess of the inner ring.

18. A bearing assembly as claimed in claim 16 or 17 when dependent on claim 7, wherein the outer diameter of the inner ring at the portion where the lubricating oil guide element is mounted is smaller than the outer diameter of the recess through which the bearing support extends.

19. 20. A pump comprising at least one rotatable shaft supporting a rotor in a stator, said at least one rotatable shaft being mounted on at least one bearing assembly according to claims 1 to 18.

20. 20. The pump of claim 19, wherein the pump comprises a lubricating oil reservoir on one axial side of the bearing assembly and a lubricating oil recovery mechanism on the other axial side, the lubricating oil guide element is configured to guide lubricating oil onto the lubricating oil recovery mechanism, and the pump further comprises a lubricating oil transfer mechanism for transferring the lubricating oil from the lubricating oil recovery mechanism to the lubricating oil reservoir.

21. 21. The pump of claim 19 or 20, wherein the pump comprises a vacuum pump configured to operate in multiple orientations.

22. A method for assembling a bearing assembly according to any one of claims 9 to 11, comprising the steps of: Assembling the bearing by mounting rollable elements inside the inner and outer rings; mounting a lubricating oil guide element having an annular shape on the inner ring of the bearing such that the lubricating oil guide element extends radially outward from an outer periphery of the inner ring; A method comprising:

23. 19. A method of assembling a bearing as claimed in any one of claims 12 to 18, wherein the inner ring comprises an axial extension extending axially beyond the outer ring; The method further comprises a further step, which is carried out before the step of attaching the lubricating oil guiding element, namely mounting a bearing support on the outer ring of the bearing, the bearing support comprising a radial extension extending across one end face of the outer ring towards the axial extension of the inner ring, thereby obscuring at least a portion of the annular gap between the inner and outer rings; Next, performing the step of installing the lubricating oil guiding element; Including, 23. The method of claim 22, wherein the lubricating oil guide element is mounted at a position axially farther from the rollable element than the radial extension of the bearing support, such that at least a portion of the radial extension of the bearing support is between the rollable element and the lubricating oil guide element.

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