Bearing assembly for shaft of turbine and turbine

Abstract

A bearing assembly (10) for a shaft (11) of a turbomachine is described. The bearing assembly (10) includes a shaft (11) having a radial step (111) provided by the shaft or by a separate element secured to the shaft. Furthermore, the bearing assembly (10) comprises a bearing sleeve (12) supporting the shaft (11). At least one of an axial surface (121) of the bearing sleeve (12) facing the radial step (111) and an axial section of the bearing sleeve (12) has at least one groove (122) leading to the bore (123), where a radially outer side of the at least one groove (122) is delimited by a radial side wall (124), where a radially inner side of the groove (122) is open, and where a radial cross-sectional area of the at least one groove (122) increases towards the bore (123).

Description

Technical Field

[0001] Embodiments of the present disclosure relate to bearing assemblies for shafts of turbomachines, such as turbochargers, turbo-compounds, and electric turbines. Background Art

[0002] Known supercharging systems (such as exhaust gas turbochargers) are used to increase the power requirements of internal combustion engines or fuel cell systems. In such exhaust gas turbochargers, a turbine is arranged in the exhaust gas path of the internal combustion engine or fuel cell, and a compressor is arranged upstream of the internal combustion engine or fuel cell and connected to the turbine via a common shaft. The shaft is usually supported by bearings supported in a bearing housing. Therefore, the exhaust gas turbocharger is usually composed of a rotor, a bearing assembly for the shaft, a guide housing section (compressor housing and turbine housing) and a bearing housing. The rotor includes a shaft as well as a compressor impeller and a turbine impeller.

[0003] By boosting the pressure of an internal combustion engine or charging a fuel cell through an exhaust gas turbocharger, the cylinder capacity and fuel mixture in the fuel cell are increased, significantly boosting the engine or fuel cell's power. Alternatively, the energy stored in the exhaust gas of an internal combustion engine or fuel cell can be converted into electrical or mechanical energy using a power turbine. In this case, as with an exhaust gas turbocharger, a generator or mechanical energy consumer is connected to the turbine shaft rather than the compressor.

[0004] Due to the high process pressures in the flow areas on the turbine and compressor sides, the exhaust gas turbocharger shaft is sealed against the bearing housing chamber using a suitable sealing concept. The internal pressure in the bearing housing chamber generally corresponds to atmospheric pressure. However, the gas pressure in the compressor- and turbine-side flow channels depends on the current operating point of the exhaust gas turbocharger and, at most operating points, is higher than the pressure in the bearing housing chamber. However, in certain situations, such as during partial load operation or when the engine is at a standstill, negative pressures must also be taken into account.

[0005] The rotating shaft of an exhaust gas turbocharger is typically supported by hydrodynamic fluid film bearings, but the required oil is taken from the internal combustion engine's oil supply or, in the case of fuel cells, from an external supply. In addition to supplying oil to the bearings, the oil can also be used to cool the supercharging system or the power turbine, depending on the application. The lubricating oil supplied to the bearings and cooling holes (usually splash holes) collects in the bearing housing, from where it exits the bearing housing via a drain.

[0006] The shaft seals between the bearing housing and the turbine or compressor are used to prevent oil from leaking into the gas paths of these components. Idle or partial load conditions in internal combustion engines are particularly critical with regard to oil tightness, as under these operating conditions, slight overpressures of only a few millibars can occur in the bearing housing. These overpressures are often sufficient to create a positive pressure gradient across the shaft seal, meaning that the pressure inside the bearing housing is higher than on the compressor or turbine side. Positive pressure gradients are often the main cause of oil leaks, as air and oil are drawn through the seals from the bearing housing into the gas paths of these components. The oil in the sealing area runs the risk of coking, which in turn leads to increased wear and, in the worst case, seal failure, resulting in the failure of the entire supercharging system or power turbine. Therefore, constant care must be taken to ensure that the shaft seals are functioning properly and sealing efficiently.

[0007] Therefore, in view of the foregoing, there is a need for an improved bearing assembly for a shaft of a turbomachine that at least partially overcomes the problems of the prior art. Summary of the Invention

[0008] In view of the above, there is provided a bearing assembly according to independent claim 1. Further aspects, advantages and features are apparent from the dependent claims, the description and the accompanying drawings.

[0009] More specifically, according to one aspect of the present disclosure, a bearing assembly for a turbine shaft is provided. The bearing assembly includes a shaft having a radial step provided by the shaft or by a separate element fixed to the shaft. Furthermore, the bearing assembly includes a bearing sleeve supporting the shaft. An axial surface of the bearing sleeve facing the radial step and at least one of an axial section of the bearing sleeve have at least one groove leading to a bore. The radial outer side of the at least one groove is defined by a radial sidewall, the radial inner side of the at least one groove is open, and the radial cross-sectional area of ​​the at least one groove increases toward the bore.

[0010] Thus, an improved bearing assembly is provided compared to the prior art. In particular, the bearing assembly advantageously provides improved oil tightness. Furthermore, embodiments of the bearing assembly described herein provide for redirection of oil flow from the bearing, which in turn helps reduce internal oil loading of the shaft seal in the bearing housing of the supercharged system. Furthermore, the bearing assembly described herein provides a more compact design, particularly in the axial direction, compared to the prior art.

[0011] According to another aspect of the present disclosure, a turbomachine is provided, comprising a bearing assembly according to any embodiment described herein. In particular, the turbomachine may be a turbocharger, a compound turbine or an electric turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to understand the above features of the present disclosure in detail, a more detailed description of the present disclosure, which has been briefly summarized above, can be obtained by referring to the embodiments. The drawings related to the embodiments of the present disclosure are described as follows:

[0013] Figure 1 shows a schematic cross-sectional view of a bearing assembly according to embodiments described herein;

[0014] Figure 2 shows a schematic cross-sectional view of a bearing assembly according to another embodiment described herein;

[0015] Figure 3 shows a schematic perspective view of a bearing sleeve according to an embodiment described herein;

[0016] Figure 4 Shown Figure 3 The enlarged part;

[0017] Figure 5 A schematic cross-sectional view of a bearing sleeve according to embodiments described herein is shown, illustrating an axial section of the bearing sleeve having at least one slot leading to a bore.

[0018] Figure 6 Shown along Figure 5 A front cross-sectional view of the line AA indicated in FIG. DETAILED DESCRIPTION

[0019] Reference will now be made in detail to various embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. In the following description of the figures, like reference numerals represent like parts. Generally, only the differences with respect to various embodiments are described. Each example is provided by way of explanation of the present disclosure and is not meant to limit the present disclosure. In addition, features shown or described as part of one embodiment can be used on other embodiments or in combination with other embodiments to produce yet another embodiment. This description is intended to include such modifications and variations.

[0020] In the following description of the accompanying drawings, the same reference numerals represent the same or similar parts. Generally, only the differences with respect to the various embodiments are described. Unless otherwise stated, the description of a part or aspect in one embodiment also applies to the corresponding part or aspect in another embodiment.

[0021] Reference Figures 1 to 6 , a bearing assembly 10 for a shaft 11 of a turbomachine is described according to an embodiment of the present disclosure.

[0022] According to an embodiment, which can be combined with other embodiments described herein, the bearing assembly 10 includes a shaft 11 having a radial step 111. The radial step 111 can be provided by the shaft or by a separate element fixed to the shaft. In particular, the radial step 111 can be an integral part of the shaft, or the radial step can be provided by a separate element attached to the shaft such that, during operation, the separate element rotates with the shaft. For example, the separate element fixed to the shaft can be a sleeve. Figure 1 and Figure 2 An example is shown where the radial step 111 is an integral part of the shaft 11. Figure 1 and Figure 2 As shown, the radial step 111 is generally provided by a step from a first radius R1 to a second radius R2, the second radius R2 being greater than the first radius R1. Typically, the second radius R2 is R2≥1.22R1, particularly R2≥1.4R1, and more particularly R2≥1.6R1.

[0023] In addition, if Figure 1 and Figure 2 As shown, the bearing assembly 10 includes a bearing sleeve 12 supporting a shaft 11. At least one of an axial surface 121 of the bearing sleeve 12 facing the radial step 111 and an axial section 16 of the bearing sleeve 12 has at least one groove 122 leading to a hole 123. In other words, the axial surface 121 of the bearing sleeve 12 facing the radial step 111 and / or the axial section 16 of the bearing sleeve 12 has at least one groove 122 leading to the hole 123. Therefore, it should be understood that only the axial surface 121 of the bearing sleeve 12 facing the radial step 111 may have at least one groove 122 leading to the hole 123, only the axial section 16 of the bearing sleeve 12 may have at least one groove 122 leading to the hole 123, or both the axial surface 121 of the bearing sleeve 12 facing the radial step 111 and the axial section 16 of the bearing sleeve 12 may have at least one groove 122 leading to the hole 123. Figure 1 and Figure 2 An exemplary embodiment is shown, in which at least one groove 122 is provided in an axial surface 121 facing the radial step 111 . Figure 5 and Figure 6 An exemplary embodiment is shown, wherein at least one groove 122 is provided in the axial section 16 of the bearing sleeve 12. Figure 3 and Figure 4 The description of the at least one groove 122 and the hole 123 may be applied with reference to Figure 1 、 Figure 2 、 Figure 5 and Figure 6 It will be appreciated that, although not explicitly shown, two or more axial sections of the bearing sleeve may be provided with at least one groove 122 as described herein with respect to the axial section 16 .

[0024] Typically, the bearing sleeve 12 has a radial height H of the bearing sleeve 12 r The axial width W of the bearing sleeve 12 x The aspect ratio AR is AR<1. The radial height H of the bearing sleeve r It can be understood as the difference between the outer radius of the bearing sleeve and the inner radius of the bearing sleeve. Figure 3 As shown in the example, the axial width W of the bearing sleeve x It can be understood as the extension of the bearing sleeve in the axial direction. Figure 3 As shown in the example, the radial height H of the bearing sleeve is usually r corresponds to the radial extension of the axial surface 121. Therefore, the radial height H r Typically corresponds to the thickness of the radial wall of the bearing sleeve.

[0025] In the present disclosure, the at least one groove 122 may also be referred to as a delivery groove. Furthermore, the hole 123 may be referred to as a discharge hole or a discharge bore. Therefore, the expression "at least one groove 122 leading to the hole 123" may be rewritten as "at least one delivery groove leading to the discharge hole". In this regard, it is noted that the "delivery groove" is configured to deliver oil toward the discharge hole. The discharge hole is configured to provide for the discharge of oil from the delivery groove, in particular the discharge of oil toward the opposite axial surface of the bearing sleeve. Furthermore, it should be understood that during operation, the shaft 11 rotates in a direction from the starting point of the at least one delivery groove toward the discharge hole of the at least one delivery groove. For a better understanding, for Figure 3 The exemplary bearing sleeve 12 shown, during operation, extends through the shaft ( Figure 3 not shown) will rotate clockwise.

[0026] In the present disclosure, an "axial section of the bearing sleeve" may be understood as a portion of the bearing sleeve along the axial direction x. Figure 1 、 Figure 2 、 Figure 3 and Figure 5 As shown by way of example, it will be understood that the axial direction x is a direction extending along the central axis 17. Typically, the central longitudinal axes of the shaft 11 and the bearing sleeve 12 coincide and correspond to the central axis 17 shown in the figures.

[0027] For example, refer to Figure 3 and Figure 4 According to an embodiment, which can be combined with other embodiments described herein, the radially outer side of the at least one groove 122 is delimited by a radial sidewall 124. Typically, the radial sidewall 124 extends in the circumferential direction along the length of the at least one groove 122. Typically, the radially inner side of the groove 122 is open. In particular, the radially inner open side of the groove 122 extends in the circumferential direction along the length of the at least one groove 122. In other words, Figure 4 As shown, the radially outer side of the bottom 122B of the groove 122 is defined by the radial sidewall 124 , while the radially inner side of the bottom 122B of the groove 122 is not defined.

[0028] According to an embodiment, which can be combined with other embodiments described herein, the radial cross-sectional area of ​​the at least one groove 122 increases toward the hole 123. It should be understood that, at a selected angular position about the central axis 17 of the bearing sleeve 12, the radial cross-sectional area of ​​the at least one groove 122 is given by the radial width W of the at least one groove 122 multiplied by the depth D of the at least one groove 122 at the selected angular position. Thus, by varying the radial width W of the at least one groove 122 and / or varying the depth D of the at least one groove 122, the radial cross-sectional area of ​​the at least one groove 122 can be varied.

[0029] According to an embodiment, which can be combined with other embodiments described herein, the width W of the at least one groove 122 increases toward the hole 123. It should be understood that the width W of the at least one groove 122 may at least partially increase in the circumferential direction toward the hole 123. In other words, at least one circumferential section of the at least one groove 122 may have an increasing width W in the direction toward the hole 123. Alternatively, the width W of the at least one groove 122 may increase in the circumferential direction toward the hole 123 over the entire circumferential extension of the at least one groove 122.

[0030] According to an embodiment, which can be combined with other embodiments described herein, the depth D of the at least one groove 122 increases toward the hole 123. It should be understood that the depth D of the at least one groove 122 may at least partially increase in the circumferential direction toward the hole 123. In other words, at least one circumferential section of the at least one groove 122 may have an increasing depth D in the direction toward the hole 123. Alternatively, the depth D of the at least one groove 122 may increase in the circumferential direction toward the hole 123 over the entire circumferential extension of the at least one groove 122. It should be understood that according to an alternative embodiment, the depth D of the at least one groove 122 may be constant in the circumferential direction toward the hole 123, in particular, constant over the entire circumferential extension of the at least one groove 122.

[0031] According to embodiments that can be combined with other embodiments described herein, a hole 123 extends from a bottom 122B of at least one groove 122 through the bearing sleeve 12 to an opposing axial surface of the bearing sleeve 12. Typically, the hole 123 extends along the axial direction x of the shaft 11. Therefore, it should be understood that the hole 123 can extend parallel to the central axis 17 of the bearing sleeve 12.

[0032] According to an embodiment that can be combined with other embodiments described herein, at least one groove 122 extends in a circumferential direction over at least 10%, in particular at least 20%, of at least one of the axial surface 121 and the axial segment 16. In other words, the axial surface 121 facing the radial step 111 may include at least one groove 122 that extends in a circumferential direction around the central axis 17 of the bearing sleeve 12 over at least 10%, in particular at least 20%, of the axial surface 121. Additionally or alternatively, the axial segment 16 may include at least one groove 122 that extends in a circumferential direction around the central axis 17 of the bearing sleeve 12 over at least 10%, in particular at least 20% of the axial segment 16.

[0033] According to an embodiment that can be combined with other embodiments described herein, the at least one groove 122 includes two or more grooves, particularly three or more grooves, and more particularly four or more grooves. Typically, the grooves are evenly distributed along the inner circumference of at least one of the axial surface 121 of the bearing sleeve 12 facing the radial step 111 and the axial section 16 of the bearing sleeve 12. It should be understood that each of the features described with respect to the at least one groove 122 can also be applied to embodiments having two or more grooves. Thus, each of the two or more grooves can lead to a corresponding drain hole.

[0034] For example, refer to Figure 3 According to an embodiment that can be combined with other embodiments described herein, the bearing sleeve 12 includes at least one radial oil supply hole 126. Typically, the at least one radial oil supply hole 126 includes two or more radial oil supply holes, and in particular, includes three or more radial oil supply holes. Typically, the two or more radial oil supply holes are evenly distributed around the circumference.

[0035] For example, refer to Figure 3 It will be appreciated that the radial oil supply holes 126 are typically angularly positioned between the discharge holes 123. It will be appreciated that angular position refers to an angular position about the central axis 17. Specifically, the radial oil supply holes 126 may be angularly positioned between the discharge holes 123 of a first delivery trough and the start of an adjacent second delivery trough.

[0036] According to an embodiment that can be combined with other embodiments described herein, the bearing sleeve 12 is a fully floating bearing sleeve. Alternatively, the bearing sleeve 12 can be a semi-floating bearing sleeve. In particular, Figure 3As shown in the exemplary embodiment, the semi-floating bearing sleeve may have a receiving portion 127 on the radial outer surface of the bearing sleeve 12 for receiving a blocking element for blocking the bearing sleeve 12 from rotating relative to the bearing flange 13. Typically, two or more receiving portions 127, such as three or more receiving portions, may be provided on the radial outer surface of the bearing sleeve 12 to receive the blocking elements, respectively. The two or more receiving portions 127 may be evenly distributed circumferentially around the central axis 17 of the bearing sleeve 12.

[0037] It should be understood that, depending on the turbine's rotordynamic requirements, the radial bearing sleeve can be designed as either a fully floating or a semi-floating bearing. The difference is that a fully floating bearing sleeve rotates with the shaft at approximately half the shaft speed. A semi-floating bearing sleeve is fixed in position, and the lubrication gap between the bearing support and the sleeve acts purely as a squeeze film damper; the oil film does not rotate. Therefore, a fully floating bearing exhibits a roughly equal oil distribution between the internal and external lubrication gaps. In contrast, a semi-floating bearing exhibits a significantly uneven oil distribution, with up to 90% of the total radial bearing oil consumption being carried by the internal lubrication gap.

[0038] For example, refer to Figure 1 According to an embodiment that can be combined with other embodiments described herein, the radially inner side of the axial surface 121 can include a chamfer 128. Typically, the chamfer 128 is provided along the entire circumference of the radially inner side. As described herein, providing the chamfer can improve oil delivery, particularly away from the radial step 111.

[0039] According to an embodiment, which can be combined with other embodiments described herein, the bearing assembly 10 includes a radial gap G1 between the bearing flange 13 supporting the bearing sleeve 12 and the shaft 11. Alternatively, the radial gap G1 can be provided between a separate element 14 attached to the bearing flange 13 and the shaft 11. Typically, the gap G1 provides a throttling gap between the shaft sealing side 101 and the bearing side 102 of the bearing assembly 10. Figure 1 and Figure 2 As shown in the exemplary embodiment, the axial position of the radial step 111 may represent the boundary between the shaft seal side 101 and the bearing side 102. Figure 1 and Figure 2 As schematically shown, a shaft seal 15 may be provided at the shaft sealing side 101 .

[0040] According to an embodiment, which can be combined with other embodiments described herein, the radial gap G1 has a value of 0.05 mm ≤ W G1 ≤0.5mm radial width W G1 .

[0041] According to an embodiment, which can be combined with other embodiments described herein, the axial length L1 of the gap G1 is equal to the radial width W G1The ratio L1 / W G1 10≤L1 / W G1 ≤20, especially L1 / W G1 =15±2.5.

[0042] For example, refer to Figure 2 According to an embodiment that can be combined with other embodiments described herein, the bearing sleeve 12 has a radially outer axially extending protrusion 129 that extends at least partially over the radial step 111 for providing a radial gap G2 between the axially extending protrusion 129 and the shaft 11 or a separate element (not shown) fixed to the shaft and providing the radial step 111. Typically, the protrusion 129 provided on the bearing sleeve is connected to the bearing flange (not shown) or the separate element 14 ( Figure 1 and Figure 2 However, it should be understood that in the case of implementing an axially extending protrusion 129, the radial gap G1 and the axial gap G4 may be omitted.

[0043] According to an embodiment, which can be combined with other embodiments described herein, the axial length L2 of the gap G2 is equal to the radial width W G2 The ratio L2 / W G2 45≤L2 / W G2 ≤105, especially L1 / W G2 =70±15.

[0044] According to embodiments, which can be combined with other embodiments described herein, the ratio (R1-R2) / W G3 20≤(R1-R3) / W G3 ≤40, especially (R1-R2) / W G3 =30±6, where R1-R2 is the radial length of the axial gap G3 between the surface 121 of the bearing sleeve 12 facing the radial step 111 and the radial step 111, and where W G3 is the axial width of the gap G3.

[0045] According to an embodiment, which can be combined with other embodiments described herein, the radial gap G2 between the axially extending protrusion 129 and the shaft 11 has a value of 0.025 mm ≤ W G2 ≤0.5mm radial width W G2 .

[0046] Providing one or more of the gaps G1 , G2 , G3 , and G4 according to the configuration described herein facilitates improving oil tightness at the interface between the bearing sleeve 12 and the shaft 111 .

[0047] It should be understood that embodiments of the bearing assembly described herein may be applied to any type of turbomachine, such as a turbocharger, a compound turbine, or an electric turbine.

[0048] Therefore, according to another aspect of the present disclosure, a turbomachine, in particular at least one of a turbocharger, a compound turbine and an electric turbine, is provided, comprising a bearing assembly according to any embodiment described herein. For example, the electric turbine may be connected to a fuel cell.

[0049] Therefore, in light of the foregoing, it will be appreciated that the embodiments described herein advantageously provide an improved bearing assembly and an improved turbine. In particular, the embodiments disclosed herein advantageously provide improved oil tightness. Furthermore, the embodiments described herein provide for the redirection of oil flow from the bearing, which in turn helps reduce the internal oil load on the shaft seal within the bearing housing of the supercharger system. Furthermore, compared to the prior art, the embodiments disclosed herein provide for a more compact design, particularly in the axial direction.

[0050] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be envisaged without departing from the basic scope thereof, and the scope of the disclosure is determined by the claims that follow.

[0051] Reference numerals

[0052] 10 Bearing assembly

[0053] 101 Shaft seal side

[0054] 102 bearing side

[0055] 11 axes

[0056] 111 radial steps

[0057] 12 bearing sleeve

[0058] 121 Axial surface of bearing sleeve

[0059] 122 troughs / conveying troughs

[0060] Bottom of 122B slot

[0061] 123 holes / drain holes

[0062] 124 radial sidewall of the groove

[0063] 126 oil supply hole

[0064] 127 Receiving Department

[0065] 128 Chamfer

[0066] 129 Protrusion

[0067] 13 Bearing flange

[0068] 14 independent components

[0069] 15 Shaft seal

[0070] 16 Axial section

[0071] 17 Central Axis

[0072] 18 Entrance hole

[0073] x-axis

[0074] r Radial

[0075] R1 first radius

[0076] R2 Second radius

[0077] G1 Radial clearance between oil pan and shaft

[0078] G2 Radial clearance between the protruding part of the bearing sleeve and the shaft

[0079] The axial direction between the axial surface of the radial step facing the shaft and the axial step surface of the G3 bearing sleeve

[0080] gap

[0081] G4 Between the protrusion of the bearing sleeve and the bearing flange or between the protrusion of the bearing sleeve and the flange attached to the bearing

[0082] Axial clearance between the individual elements of the flange

[0083] L1 G1 length

[0084] L2 G2 length

[0085] W slot width

[0086] Depth of D groove

Claims

1. A bearing assembly (10) for a shaft (11) of a turbine, the bearing assembly comprising: - the shaft (11) having a radial step (111) provided by the shaft or by a separate element fixed to the shaft, - a bearing sleeve (12) supporting the shaft (11), wherein at least one of an axial surface (121) of the bearing sleeve (12) facing the radial step (111) and an axial section (16) of the bearing sleeve (12) has at least one groove (122) leading to a hole (123), wherein the radial outer side of the at least one groove (122) is delimited by a radial side wall (124), wherein the radial inner side of the at least one groove (122) is open, and wherein the radial cross-sectional area of ​​the at least one groove (122) increases towards the hole (123).

2. The bearing assembly (10) according to claim 1, wherein The width W of the at least one groove (122) increases toward the hole (123).

3. The bearing assembly (10) according to claim 1 or 2, wherein: The hole (123) extends from the bottom of the at least one groove through the bearing sleeve (12) to the opposite axial surface of the bearing sleeve (12), and in particular the hole (123) extends along the axial direction x of the shaft (11).

4. The bearing assembly (10) according to any one of claims 1 to 3, wherein: The at least one groove (122) extends in the circumferential direction over at least 10%, in particular at least 20%, of at least one of the axial surface (121) and the axial section.

5. The bearing assembly (10) according to any one of claims 1 to 4, wherein: The at least one groove (122) includes two or more grooves, particularly three or more grooves, more particularly four or more grooves, wherein the grooves are uniformly distributed in the inner circumference of at least one of the axial surface (121) of the bearing sleeve (12) facing the radial step (111) and the axial section of the bearing sleeve (12).

6. The bearing assembly (10) according to any one of claims 1 to 5, wherein: The bearing sleeve (12) includes at least one radial oil supply hole (126).

7. The bearing assembly (10) according to any one of claims 1 to 6, wherein: The bearing sleeve (12) is a fully floating bearing sleeve or a semi-floating bearing sleeve. In particular, the semi-floating bearing sleeve has a receiving portion (127) on the radial outer surface of the bearing sleeve (12) for receiving a blocking element for blocking the bearing sleeve (12) from rotating relative to the bearing flange (13).

8. The bearing assembly (10) according to any one of claims 1 to 7, wherein: The radially inner side of the axial surface (121) includes a chamfer (128).

9. The bearing assembly (10) according to any one of claims 1 to 8, further comprising a radial gap (G1) between a bearing flange (13) supporting the bearing sleeve (12) or a separate element (14) attached to the bearing flange 13 and the shaft (11), in particular, wherein the gap (G1) provides a throttling gap between the shaft sealing side (101) and the bearing side (102) of the bearing assembly (10).

10. The bearing assembly (10) according to claim 9, wherein: The radial gap (G1) has a value of 0.05 mm ≤ W G1 ≤0.5mm radial width W G1 .

11. The bearing assembly (10) according to any one of claims 1 to 10, wherein: The bearing sleeve (12) has a radially outer axially extending protrusion (129), which extends at least partially on the radial step (111) to provide a radial gap (G2) between the axially extending protrusion (129) and the shaft (11).

12. The bearing assembly (10) according to claim 11, wherein The radial gap (G2) between the axially extending protrusion (129) and the shaft (11) has a value of 0.025 mm ≤ W G2 ≤0.5mm radial width W G2 .

13. The bearing assembly (10) according to any one of claims 1 to 12, wherein: The bearing sleeve (12) has a radial height H of the bearing sleeve (12) r The axial width W of the bearing sleeve (12) x The aspect ratio AR is AR<1, wherein the radial height H of the bearing sleeve (12) is r is the difference between the outer radius of the bearing sleeve and the inner radius of the bearing sleeve.

14. A turbomachine, in particular at least one of a turbocharger, a compound turbine and an electric turbine, comprising a bearing assembly (10) according to any one of claims 1 to 13.

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