DE102016222625A1 - Bearing bushing for a shaft of a turbocharger - Google Patents

Abstract

The invention relates to a bearing bushing for a shaft of a turbocharger, having at least one annular thrust bearing surface comprising at least a number of wedge surfaces which follow one another in the circumferential direction. The bearing bush according to the invention is characterized in that the wedge surfaces start in a plane perpendicular to the central axis of the bearing bush and descend from said plane in the axial direction along the circumferential direction, each of the wedge surfaces terminating at an edge of the adjacent wedge surface with a step in the axial direction below the plane.

Description

The invention relates to a bearing bush for a shaft of a turbocharger according to the closer defined in the preamble of claim 1. The invention also relates to a turbocharger with such a bushing.

Turbochargers are known from the general state of the art. Typically, they have a continuous shaft, on one end of which a turbine is mounted and on the other end of which at least one compressor wheel is mounted. For the storage of the shaft in a housing of the turbocharger bearing bushes have long been established, which in particular have thrust bearing surfaces and radial bearing surfaces. By way of example, a bearing bush of this kind in the disclosure of US 4,240,678 A be pointed out.

A crucial point in such bearing bushes is their bearing task on the one hand as a thrust bearing and in particular as a radial bearing for the typically with several 10000 rev / min very fast running shaft of the turbocharger. Such sockets can be integrally formed. This can be exemplified by the structure in the US 6,017,184 A be pointed out. It shows, for example, the EP 1 998 009 B1 a structure in which a split socket is formed. This split into two parts socket essentially has a similar structure of both the radial bearing surfaces in the interior of the two bushes and the thrust bearing surfaces on each end face of the socket.

The US 9,140,185 B2 shows in addition to the main purpose of the patent, which describes an asymmetrical opening for receiving a positioning pin for fixing the bearing bush in the housing of the turbocharger, also a thrust bearing surface. The thrust bearing surface is for example in 2 shown. It consists of bearing surfaces and wedge surfaces which alternate in the circumferential direction. In addition to these additional grooves are shown in the radial direction increasing from the inner diameter to the outer diameter with two different shapes. The shape of the entire thrust bearing surface is very complex and difficult to manufacture. In addition, a relatively high degree of friction is caused by a number of edges.

The international patent application WO 2014/055255 A1 shows a plain bearing with a thrust bearing surface. The thrust bearing surface consists of a flat surface with pressure generating means on the inner diameter of the annular surface. These pressure-generating means do not extend to the outer diameter of the surface. They are used to bring oil as a lubricant to the flat surface. The problem with this idea is the relatively large flat surface which increases the friction. In addition, no means are provided to distribute the oil over the flat surface. Although this requires only a minimal amount of oil, on the other hand, it further increases friction.

It is the object of the invention to provide an improved bushing for the shaft of a turbocharger, which allows good bearing capacity along with minimal friction and acceptable oil consumption. It is also the object of the invention to provide a turbocharger with such a bushing.

This object is achieved by a bearing bush with the features in claim 1. The object is also achieved by a turbocharger with such a bushing.

The bearing bush according to the invention comprises, as an axial bearing surface, an arrangement of a number of wedge surfaces which follow one another in the circumferential direction. Each of the wedge surfaces starts in a plane perpendicular to the central axis of the bearing bush. It decreases from this plane in the axial direction along the circumferential direction, wherein each of the wedge surfaces terminates at one edge to the adjacent wedge surface with a step in the axial direction below the plane. This complex three-dimensional surface allows a design with a minimum number of edges. Therefore, as much bearing capacity or pressure build-up as possible can be achieved, with minimal disturbance of the flow of the lubricant on and in the area of the axial bearing surface. A good load capacity together with a low friction is achieved hereby.

In an advantageous development of the invention, the axial bearing surface comprises an alternating arrangement of wedge surfaces and latching surfaces with respect to the circumferential direction. The locking surfaces are flat and arranged in a plane. This plane is aligned perpendicular to the central axis of the bearing bush. Each of the wedge surfaces starts adjacent to an edge of the locking surfaces in the same plane. It then drops in the axial direction along the circumferential direction from this plane, the wedge surfaces at the other end of the next latching surface terminating in the circumferential direction with a step in the axial direction below the planar latching surface.

According to an advantageous embodiment of the bearing bush, the height of the step at the inner diameter of the thrust bearing surface is greater than at the outer diameter of the thrust bearing surface. In a preferred embodiment, the height at the inner diameter is at least three times, preferably more than five times greater than the height of the step at the outer diameter. That allows a good supply with oil as a lubricant from the inside of the bearing bush to the wedge surfaces. On the other hand, it reduces the amount of lubricant that gets to the outer diameter and is thrown away by the rotating elements. As a result, a good lubrication on the one hand and a reduction of the required amount of lubricant on the other hand is achieved.

In order to achieve these particular improvements, the wedge surface has a steadily curved shape. There are no edges in the wedge surface. The transition from the flat locking surface into the wedge surface can be unsteady. The rest of the shape of the wedge surface has a three-dimensional continuous curved shape. The shape is preferably continuous in the radial direction and in the circumferential direction. As a result, a minimal resistance to the lubricant is possible and achieved a good load capacity.

According to an advantageous embodiment of the bearing bush, the thrust bearing surface comprises at least three, preferably four locking surfaces. With such a relatively small number of locking surfaces, the friction between the thrust bearing surface and its counterpart is reduced. Although in a preferred embodiment of the idea, the entire surface of the locking surfaces is smaller than that of the wedge surfaces, the bearing capacity of the thrust bearing surface can still be improved.

According to a further very favorable embodiment of the idea, the ratio between the latching surfaces on the one side and the wedge surfaces on the other side is approximately 1: 2, or smaller. This helps to reduce friction and, due to the special design of the wedge surfaces, allows an acceptable bearing capacity of the thrust bearing surface.

Furthermore, it is provided in an improved embodiment that the edges between the locking surfaces and the wedge surfaces extend in the radial direction. The preferably annular surface of the thrust bearing surface is thus divided into radial segments of the wedge surfaces and the locking surfaces, which follow one another in an alternating arrangement.

Although it is conceivable that a bearing bush only has such a thrust bearing surface, it is provided according to an advantageous development of the idea that the bearing bush is characterized in that two Axiallagerflächen are provided on each of its two axial end faces. According to the special design of the wedge surfaces, it is helpful to provide a distribution of lubricant from the inside of the bearing bush to the wedge surfaces. According to this idea, the bearing bush comprises oil distribution means, which are arranged inside the peripheral surface of the bearing bush.

According to an advantageous development of this idea, the bearing bush comprises at least one radial bearing surface on its inner surface, which has a groove for oil distribution. Such a groove in at least one radial bearing surface on the inner peripheral surface of the bushing allows the distribution of oil in the axial direction from the center of the bushing through the radial bearing surfaces in the region of the thrust bearing surface. As a result, both the lubrication of the radial bearing surface and the thrust bearing surface is possible.

According to a further very advantageous development, it is provided that the groove for the oil distribution in the radial bearing surface is formed as a spiral groove. This helical groove, when configured in the required rotational direction, allows oil to be transported outwardly from the center of the bushing in an axial direction.

A turbocharger according to the invention comprises at least a compressor and a turbine on a common shaft. The turbocharger further includes a housing having a central opening for receiving the shaft in at least one bushing. The bushing is constructed according to one of the above-described embodiments with an axial bearing surface comprising wedge surfaces according to the embodiments described above. Such a turbocharger allows minimal friction in its thrust bearings and allows good carrying capacity with a low consumption of lubricant or oil.

Further advantageous embodiments and further developments of the bearing bush and the turbocharger also result from the exemplary embodiment, which is described in more detail below with reference to the figures.

• 1 einen Schnitt durch einen Teil eines Turboladers gemäß der Erfindung;
• 2 eine Schnittdarstellung durch die im Gehäuse des Turboladers eingesetzte Lagerbuchse;
• 3 eine dreidimensionale Ansicht einer Lagerbuchse in einer erfindungsgemäßen Ausgestaltung;
• 4 eine Draufsicht auf eine Ausgestaltung der Axiallagerfläche in einer erfindungsgemäßen Ausgestaltung;
• 5 eine dreidimensionale Ansicht einer Axiallagerfläche in einer ersten Ausgestaltung gemäß der Erfindung; und
• 6 eine dreidimensionale Ansicht einer Axiallagerfläche in einer weiteren Ausgestaltung gemäß der Erfindung.

Showing:

• 1 a section through a part of a turbocharger according to the invention;
• 2 a sectional view through the bearing bush used in the housing of the turbocharger;
• 3 a three-dimensional view of a bearing bush in an embodiment of the invention;
• 4 a plan view of an embodiment of the thrust bearing surface in an embodiment of the invention;
• 5 a three-dimensional view of a thrust bearing surface in a first embodiment according to the invention; and
• 6 a three-dimensional view of a thrust bearing surface in a further embodiment according to the invention.

In the presentation of the 1 is a section of a turbocharger 1 to recognize how it can be used in particular as an exhaust gas turbocharger. The core of the turbocharger 1 form a turbine 2 and on a common wave 4 with this turbine 2 a compressor 3 , at the other end of the wave 4 , The turbocharger 1 itself consists of a central housing 5 in which a bearing bush 6 for storage of the shaft 4 is arranged. The central housing 5 is then laterally in the area of the compressor 3 through an attached compressor housing 7 and in the area of the turbine 2 through a turbine housing 8th completed. For the following invention is now in particular the central region of the housing 5 as well as the bearing bush 6 for the axial and radial support of the shaft 4 Interesting.

In the enlarged section of the 2 is the central part of the case 5 as well as the bearing bush 6 , this time without the wave 4 to recognize again. The bearing bush 6 sits in a central opening 9 of the housing 5 , The diameter of this central opening 9 is constant over the entire axial length, wherein the axial direction a, as shown in the illustration of 2 is indicated along a central axis 10 , which is the axis of rotation of the shaft 4 and the turbine 2 as well as the compressor 3 is defined. The radial direction R is perpendicular to this central axis 10 ,

The bearing bush 6 gets into the central opening during assembly with slight play 9 pushed in, for example, before the shaft 4 in the bearing bush 6 is pushed in or possibly even if this on the shaft 4 is plugged. After insertion into the central opening 9 comes a hole 11 , which also as an oil drain hole 11 is referred to, so over a stepped bore 12 in the case 5 to lie that one pen 13 for example, by screwing into a thread of the stepped bore 12 with its front end within the oil drain hole 11 to come to rest. The bearing bush 6 is through the pen 13 both with play in the axial direction A as well as in the radial direction R fixed. The bearing bush 6 So it can be in the central opening 9 still moving, but can not get out of the central opening 9 out.

The bearing bush 6 itself has an outer surface 14 as well as an inner surface 15 on. The outer surface 14 is analogous to the design of the central opening 9 outside the grooves 18 . 19 . 20 which it has, and with the exception of one transition each 28 designed to the front sides with the same diameter. This is in the presentation of 3 , a three-dimensional representation of the bearing bush 6 to recognize even better. The housing 5 shows how it turns in 2 can be seen, also on the stepped bore 12 opposite side of an oil supply passage 16 on, about which lubricating oil according to the arrow designated 17 in the illustration of 1 to the bushing 6 is supplied. The lubricating oil then passes, centrally in the area of the bearing bush 6 , There is a groove on the one hand 18 , These in the axial direction A running groove 18 , which also as a longitudinal groove 18 is referred to, extends over the approximately entire length of the bearing bush 6 , Only in the axial end regions are parts of the outer surface 14 , which of the longitudinal groove 18 not be penetrated so that the groove 18 does not flow into the area of the end faces. In addition to the longitudinal groove extending in the axial direction 18 Of course, a groove would also be conceivable which extends only with a directional component in the axial direction. Such a groove could, for example, oblique, V-shaped, zigzag or spiral around the bearing bush 6 run. Essentially, however, the same applies to them, which is illustrated here by the example of the axial longitudinal groove 18 is executed accordingly.

In the area of the oil supply channel 16 is in the assembled state of the bearing bush 6 also one in the representations of the 3 recognizable circumferential central groove 19 , which as an annular groove around the circumference of the bearing bush 6 is trained. In the area where the in the axial direction A extending longitudinal groove 18 ends, there is also at each end a further annular groove, which are each denoted by 20 in the illustrations of the figures. The end of the bearing bush 6 form two thrust bearing surfaces 21 on the front sides of the bearing bush 6 ,

In the presentation of the 2 are now in particular the longitudinal groove 18 as well as the two ring grooves 20 to recognize. From these two ring grooves 20 each lead two oppositely disposed radial bores 22 from the outside surface 14 or the annular grooves 20 in the area of the inner surface 15 as shown in particular in the presentation of 2 is very easy to recognize. In this area is the inner diameter of the bearing bush 6 reduced, so here radial bearing surfaces 23 form, which for the radial mounting of the shaft 4 at suitable shaft sections, as shown in the illustration of the 1 is apparent, are suitable.

About the oil supply channel 16 now passes according to the in 1 Arrow indicated 17 oil as a lubricant in the region of the longitudinal groove 18 as well as the central groove 19 , Part of the oil is flowing through the longitudinal groove 18 to the two annular grooves 20 and distributed around the circumference of the bearing bush 6 , This oil then flows through the radial bores 22 in the area of radial bearing surfaces 23 where it serves to lubricate the radial bearing surfaces 23 , The number of radial bores 22 in the area of each of the radial bearing surfaces 23 is ideally even over the circumference of the bearing bush 6 or the annular groove 20 distributed to ensure even lubrication. Advantageously, it is such that, as in the structure according to the figures, only two radial bores 22 available. This ensures on the one hand sufficient lubrication of the radial bearing surfaces 23 , On the other hand, due to the comparatively small number of only two radial bores 22 per radial bearing surface 23 the lubricating oil consumption is limited, which also represents a not to be underestimated advantage.

Furthermore, it is in the representation of 2 to recognize that in each of the two radial bearing surfaces 23 each a spiral groove 29 is arranged. This spiral groove winds along the entire radial bearing surface 23 and is in the one radial bearing surface 23 in the opposite sense of rotation as in the other of the radial bearing surfaces 23 trained, as can be seen from the presentation of 2 is apparent. The lubricating oil, which over the longitudinal groove 18 and the radial bores 22 in the area of radial bearing surfaces 23 now passes through these two spiral grooves 29 over the entire radial bearing surfaces 23 distributed. This provides a comparatively good lubrication over the entire surface of the radial bearing surfaces 23 for sure. At the same time a direct outflow, as would be the case for example in longitudinal grooves in the radial bearing surfaces, prevented. Nevertheless, it happens, by the direction of rotation of the spiral grooves 29 to a certain conveying effect due to the opposite to the radial bearing surfaces 23 relatively rotating shaft 4 , In this way, a conveying effect on the oil in the axial direction in each case to the outside, ie in the direction of the thrust bearing surfaces 21 , scored. This will provide a safe and reliable lubrication of the thrust bearing surfaces 21 guaranteed during operation.

From the radial bearing surfaces 23 arrives despite the spiral grooves 29 Nevertheless, a small part of the oil inside in the area of the bearing bush 6 between the two radial bearing surfaces 23 , This portion of the oil can then pass through the oil drain port 11 and the pen 13 , which has a longitudinal through hole 24 as it is in the 1 and 2 to recognize, flow away. Another part of the oil flows through the radial bearing surfaces 23 to the outside and enters the area of the thrust bearing surfaces 21 to the front sides of the bearing bush 6 , He smears there the thrust bearing surfaces 21 and then flows outwards, as shown in the illustration of 3 can be seen. He gathers in an annulus 25 around the shaft 4 and flows as indicated by the arrows indicated at 26, together with the oil which the through-bore 24 happens through a drainage hole 27 out of the case 5 from. An oil passage in the direction of the turbine 2 or the compressor 3 is prevented in a conventional manner by seals, here labyrinth seals.

In addition to this oil, which is the lubrication of the radial bearing surfaces 23 and the thrust bearing surfaces 21 serves, a part of the oil also flows from the annular central groove 19 along a gap between the outer surface 14 the bearing bush 6 and the surface of the central opening 9 from. Through this gap, the oil is also in the axial direction A to the outside, ie in each case in the direction of the thrust bearing surfaces 21 go through. This passage of the oil through the comparatively narrow gap between the outer surface 14 and the area of the central opening 9 acts on the one hand for lubrication and especially as Quetschöldämpfer, which the potentially occurring wobble of the bearing bush 6 as far as these are in the central opening 9 Game has dampened, and so for a calm and reliable wave 4 of the turbocharger 1 provides. Also on this way reaches the oil of Quetschöldämpfers, which also from the annular grooves 22 flows in the axial direction to the outside and there also causes a damping, in the region of the thrust bearing surfaces 21 and smear these. Excess oil then passes through the surrounding annular spaces 25 and the indicated arrows 26 , like in the 1 recognizable, over the drainage opening 27 out of the case 5 ,

Furthermore, in 3 on one of the axial end faces 21 the bearing bush 6 an axial bearing surface 30 shown. The thrust bearing surface 30 has an annular contour and consists of four locking surfaces 31 and four wedge surfaces 32 , The locking surfaces 31 and the wedge surfaces 32 follow each other in an alternating manner around the circumference of the annular thrust bearing surface 30 , The locking surfaces 31 are in a plane which is perpendicular to the orientation of the central axis 10 the bearing bush is, just arranged. The lubricant or oil passing through the spiral grooves 29 in the radial bearing surfaces 23 in the direction of the front ends 21 the bearing bush 6 is promoted, distributed at the inner diameter d the thrust bearing surface 30 which is in 4 is shown. The surface of the plane locking surfaces 31 is smaller than the area of the wedge surfaces 32 which is also very good in the top view of the 4 can be recognized. The area of the locking surfaces 31 is less than 50%, preferably less than 33% of the total area of the thrust bearing surface 30 , In this particular embodiment, which in 4 is shown, the area is the latching surfaces 31 in about 25%, wherein the area of the wedge surfaces about 75% each of the total area of the thrust bearing surface 30 is.

In the enlarged view of 5 is the design principle of the wedge surfaces 32 to recognize. Each of the wedge surfaces 32 begins in the same plane as the flat locking surfaces 31 , In the presentation of the 5 this is always at a radial edge 33 the locking surfaces in the clockwise direction. Starting from this edge 33 the wedge surface is descending in the axial direction from this plane perpendicular to the central axis 10 designed. It rises at the outer diameter D the annular thrust bearing surface 30 only for a small amount. The amount by which they are at the inner diameter d the annular thrust bearing surface descends is higher. This leads to a stage 34 at the circumferential end of the wedge surface in the clockwise direction. This level 34 , which preferably extends in the radial direction, has a further edge 35 to each of the locking surfaces 31 ,

When using the bearing bush 6 in the turbocharger 1 rotates the thrust bearing surface 30 in a counterclockwise direction with respect to a mating surface (not shown), which may be flat, for example. This rotation of the bearing bush 6 in the counterclockwise direction requires a thrust bearing surface 30 on the other side 21 the bearing bush 6 , which opposite the thrust bearing surface 30 is mirrored in the figures.

As can be seen from the view in 5 is a height H at the inner diameter d the stage 34 much higher than a height H at the outer diameter D , This leads to a three-dimensionally curved shape of the wedge surface 32 which is steady. This means that they have no other edges in the surface of the wedge surface 32 having.

The way in which the wedge surfaces 32 With respect to the flat locking surfaces are dimensioned, that is that on the inner diameter d the level higher than the outer diameter D is. The height H at the inner diameter d is about three to eight times higher than the height H at the outer diameter D , In the embodiment, which in 5 shown is the height H in about 20-60 microns while the height H 150-300 μm. This complex three-dimensional shape of the wedge surface allows a good lubrication with minimal friction and high load capacity on the one hand and allows the reduction of the consumption of oil or lubricant on the other.

In the direction of rotation in the clockwise direction has continued the locking surface 31 the other radial edge 33 which is the edge at which the next adjacent wedge surface 32 starts. The combination of locking surfaces 31 , Wedge surfaces 32 and the stage 34 is around the circumference of the annular thrust bearing surface 30 arranged four times in the preferred embodiment and all four locking surfaces 31 as well as the wedge surfaces 32 are of the same size and type to obtain a uniform distribution of the entire area of the thrust bearing surface. Such a thrust bearing surface 30 is on both ends 21 arranged as it is in 2 is shown.

The embodiment which is in 6 is shown is without the locking surfaces 31 executed. Four wedge surfaces 32 follow each other in the circumferential direction. The stage 34 is therefore between the individual wedge surfaces 32 arranged yourself. Each of the wedge surfaces 32 starts in the plane perpendicular to the central axis 10 the bearing bush 6 , The design of their shape follows the same design principles as the previously described wedge surfaces 32 , The surface therefore drops along the circumferential direction starting in the plane and ends with a step 34 which leads the surface back to the plane. This allows the substantially same function as in the embodiment described above. The friction can be reduced even further.

In addition, the distribution of the oil over the axially extending groove 18 and the spiral groove 29 in the radial bearing surfaces 23 just an example of the design of the bearing bush with the thrust bearing surfaces 30 according to the invention. It will be readily apparent to one skilled in the art that the invention may be used with other types of oil supply and / or radial bearing surfaces.

LIST OF REFERENCE NUMBERS

1

turbocharger

2

turbine

3

compressor

4

wave

5

casing

6

bearing bush

7

compressor housing

8th

turbine housing

9

central opening

10

central axis

11

Oil drain hole

12

Stepped bore in the housing 5

13

pen

14

Outer surface of the bearing bush 6

15

Inner surface of the bearing bush 6

16

Oil supply channel

17

Oil supply (arrow)

18

in the axial direction extending longitudinal groove

19

central groove

20

ring grooves

21

axial bearing

22

radial bores

23

Radial bearing surfaces

24

Through hole in pin 13

25

annulus

26

Oil removal (arrows)

27

drainage opening

28

crossing

29

spiral groove

30

thrust bearing

31

Rest area

32

wedge surface

33

radial edge

34

step

35

radial edge

A

axial direction

R

radial direction

H

Height of the level 34 at the outer diameter

H

Height of the level 34 at the inner diameter

D

outer diameter

d

inner diameter

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 4240678 A [0002]
• US 6017184 A [0003]
• EP 1998009 B1 [0003]
• US 9140185 B2 [0004]
• WO 2014/055255 A1 [0005]

Claims (15)

Bearing bush (6) for a shaft (4) of a turbocharger (1), having at least one annular thrust bearing surface (30) comprising at least a number of wedge surfaces (32) which follow one another in the circumferential direction, characterized in that the wedge surfaces (32) start in a plane perpendicular to the central axis (10) of the bearing bush (6) and descend from this plane in the axial direction (A) along the circumferential direction, wherein each of the wedge surfaces (32) at an edge of the adjacent wedge surface with a step in the axial direction ends below the level. Bearing bush (6) to Claim 1 , characterized in that the axial bearing surface (30) further comprises latching surfaces (31) which are plane in the plane perpendicular to the central axis (10) of the bearing bush (6), and that the latching surfaces (31) and the wedge surfaces (32) in Circumferentially arranged circumferentially, wherein the wedge surfaces (32) on one edge (35) of the latching surface (31) start and wherein the step between the wedge surface and the other edge (33) of the adjacent latching surface (31) is arranged. Bushing (6) according to Claim 1 or 2 , characterized in that the height (H) of the step (34) at the inner diameter (d) of the thrust bearing surface (30) is greater than at the outer diameter (D) of the thrust bearing surface (30). Bushing (6) according to Claim 3 , characterized in that the height (H) at the inner diameter (d) is at least three times higher than the height (h) of the step (34) at the outer diameter (D). Bearing bush (6) according to one of Claims 1 to 4 , characterized in that the wedge surfaces (32) have a continuous curved shape. Bearing bush (6) according to one of Claims 1 to 5 , characterized in that the outer diameter (D) and the inner diameter (d) of the thrust bearing surface (30) are circular. Bearing bush (6) according to one of Claims 2 to 6 , characterized in that the axial bearing surface (30) at least three, preferably four, the locking surfaces (31). Bearing bush (6) according to one of Claims 2 to 7 , characterized in that the entire surface of the latching surfaces (31) is smaller than that of the wedge surfaces (32). Bushing (6) according to Claim 8 , characterized in that the entire surface of the latching surfaces (31) constitutes less than one third of the total area of the thrust bearing surface (30). Bearing bush (6) according to one of Claims 2 to 9 , characterized in that the edges (33, 35) extend between the latching surfaces (31) and the wedge surfaces (32) in the radial direction (R). Bearing bush (6) according to one of Claims 1 to 10 characterized by two thrust bearing surfaces (30) at its two axial end faces (21). Bearing bush (6) according to one of Claims 1 to 11 , characterized in that oil distribution means are arranged at least on the inner surface (15) of the bearing bush. Bushing (6) according to Claim 12 , characterized in that at least one radial bearing surface (23) on the inner surface (15) has a groove (29) for oil distribution. Bushing (6) according to Claim 13 , characterized in that the groove is a helical groove (29). Turbocharger (1) having at least one compressor (3) and a turbine on a common shaft (16) with a housing (12) having a central opening for receiving the shaft in at least one bearing bush, characterized by the bearing bush (6) according to one or more several of the Claims 1 to 14 ,

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