DE102017106478B4 - Bearing outer ring for a radial roller bearing as well as radial roller bearing - Google Patents

Abstract

Bearing outer ring (20) of a radial roller bearing (3) in an exhaust gas turbocharger (1), with an outer circumferential surface (21 a, 21b) on which at least one circumferential supply groove (22a, 22b) is arranged, with the outer circumferential surface (21a, 21b) of the Radial roller bearing (3) and a housing (2) accommodating the radial roller bearing, a squeeze film gap (14) that can be supplied with oil can be formed, as well as axially directed annular end faces (29a, 29b), the bearing outer ring (20) at least one in the supply channel (26) extending in the axial direction of the bearing outer ring (20), which can be fed indirectly by one of the supply grooves (22b), and wherein the at least one supply channel (26) emerges at an end face (29a, 29b) of the bearing outer ring (20), characterized in that a circumferential collecting groove (31) is arranged on the outer jacket surface (21a) between the supply groove (22b) and the end face (29b), which lubricates oil through the squeeze film gap (14) is supplied and which opens into the supply channel (26).

Description

Field of invention

The invention relates to a bearing outer ring of a radial roller bearing in an exhaust-gas turbocharger, with an outer jacket surface on which at least one circumferential supply groove is arranged, with a squeeze film gap that can be supplied with oil and axially being able to be formed between the outer jacket surface of the radial roller bearing and a housing that accommodates the radial roller bearing directed annular end faces, the bearing outer ring having at least one supply channel extending in the axial direction of the bearing outer ring, which can be fed indirectly from one of the supply grooves, and wherein the at least one supply channel exits at an end face of the bearing outer ring. The invention also relates to a radial roller bearing.

State of the art

An exhaust gas turbocharger of an internal combustion engine has a turbine wheel, a compressor wheel and a rotor shaft that connects the turbine wheel to the compressor wheel in a rotationally fixed manner. The rotor shaft is usually rotatably arranged in a housing of the turbocharger by at least one radial roller bearing or radial plain bearing.

A radial roller bearing for an exhaust gas turbocharger can be designed as a double-row shoulder ball bearing or angular contact ball bearing to accommodate radial and axial loads. A shoulder ball bearing has a bearing inner ring configuration that is customary for deep groove ball bearings, while the bearing outer ring is provided with a shoulder. In the case of angular contact ball bearings, on the other hand, both the bearing outer ring and the bearing inner ring are provided with shoulders. A fully assembled radial roller bearing can be arranged as a bearing cartridge on a rotor shaft of an exhaust gas turbocharger. The assembly formed from the bearing cartridge and the rotor shaft can then be inserted into a housing of an exhaust gas turbocharger.

A bearing outer ring and a radial roller bearing are from the DE 10 2014 212 620 A1 known. A radial rolling bearing designed as a shoulder ball bearing for an exhaust gas turbocharger comprises an outer bearing ring, a two-part bearing inner ring arranged coaxially within the outer bearing ring, and two rows of rolling elements made of spherical rolling elements guided between the outer bearing ring and the inner bearing ring. The bearing outer ring comprises two spray oil bores which radially penetrate it and which open out on the inner circumferential surface of the bearing outer ring between the roller bearing rows. An inlet of the respective splash oil bore arranged on an outer jacket surface of the bearing outer ring is designed as an outer circumferential groove. Oil, which is used for lubrication and cooling, is supplied to the interior of the radial roller bearing through the spray oil bores. The oil supplied between the rows of rolling elements exits through an oil supply duct bore provided in the middle of the bearing outer ring in its lower area, after a large part of the oil has run down due to gravity. The oil is therefore available for cooling a housing of an exhaust gas turbocharger that accommodates the radial roller bearing, especially in the lower region of the housing. The upper area of the housing of the exhaust gas turbocharger, to which the oil would have to be actively supplied for cooling, that is, by throwing off oil that reaches the rotor shaft, and the rotor shaft, have a significantly lower oil flow available.

They also reveal US 2016/0 160 924 A1 , the DE 10 2010 063 391 A1 and the DE 10 2011 081 419 A1 one bearing outer ring and one associated roller bearing.

Disclosure of the invention

It is the object of the present invention to achieve an improvement in the cooling function.

This object is achieved by the features of the independent patent claims 1 and 8. Advantageous configurations are reproduced in the patent claims which are dependent on them and which can represent an aspect of the invention, taken individually or in various combinations with one another.

According to this, an outer bearing ring of a radial rolling bearing in an exhaust gas turbocharger is provided with an outer jacket surface on which at least one circumferential supply groove is arranged. Furthermore, the bearing outer ring has axially directed end faces. The circumferential supply groove is fed with an oil flow that is used to lubricate and cool the radial roller bearing.

According to the invention, the bearing outer ring has at least one supply channel extending in the axial direction of the bearing outer ring, which can be fed indirectly by the supply groove, the at least one supply channel emerging at one of the end faces of the bearing outer ring. The at least one supply channel is understood to mean an indirectly communicating connection between the circumferential supply groove and the adjacent end face of the bearing outer ring, through which a partial oil flow of an oil flow supplied to the supply groove is specifically branched off and directed. The Supply channel can be formed continuously from one or more sections or from several separate sections. The branched off partial oil flow exits through the at least one supply channel opening at one end face in the outer circumferential area of the bearing outer ring, that is to say at a radial distance from a rotor shaft of an exhaust gas turbocharger.

This partial oil flow can reach the rotor shaft and be thrown off from it to the outside. The integration of the at least one supply channel into the bearing outer ring is advantageous, since no structural changes are therefore required to the housing that accommodates the bearing outer ring and the associated radial roller bearing. In particular, the integration of the at least one supply channel in the bearing outer ring allows exhaust gas turbochargers that are already mass-produced to be retrofitted, since the housing does not need to be modified. In order to keep the effort in the production of the bearing outer ring low, it can be provided that the at least one supply channel is only arranged on one side of the bearing outer ring.

The at least one supply channel can face the section of the rotor shaft which carries the turbine wheel, since the temperatures are highest on this side. The bearing outer ring can be made in one piece or in several pieces.

Through the at least one supply channel, on the one hand, the volume flow that can be fed to the rotor shaft is increased and, on the other hand, a sufficient amount of oil can be fed to a housing of the exhaust gas turbocharger surrounding the rotor shaft by being thrown off the rotor shaft so that the upper area of the housing Otherwise the oil does not get into the oil due to the force of gravity, or only in very small quantities, can be cooled sufficiently.

In contrast, occurs in the oil supply according to DE 10 2014 212 620 A1 the disadvantage that the oil supplied through the supply grooves emerges in the lower area of the radial roller bearing via the oil supply channel bore, so that areas of the rotor shaft and the housing lying outside the axial extent of the radial roller bearing are not cooled.

The invention includes the technical teaching that between the supply groove and the end face an at least partially circumferential collecting groove is arranged on the outer jacket surface, which lubricating oil is supplied through a squeeze film gap and which opens into the supply channel. In this case, the partial oil flow is not fed into the supply channel directly through the supply groove, but rather through the annular squeeze film gap that forms between the outer bearing ring and the surrounding housing of the exhaust gas turbocharger. The vibration-inhibiting oil film that forms in the squeeze film gap arrives at the collecting groove that runs around at least some sections. From this the oil reaches the supply channel in the manner already described and emerges at the end face of the bearing outer ring. The collecting groove running around in sections can form a type of reservoir for the oil which was not discharged through the at least one supply channel.

The supply channel can be designed as a bore. The bore is fed with a partial oil flow directly from the supply groove. The outflow speed can be adjusted by dimensioning the bore diameter. When manufacturing the bearing outer ring, the bore is made from the end face.

Furthermore, a spray oil bore which penetrates the bearing outer ring essentially in the radial direction and opens into a supply channel designed as a through bore can be provided. The splash oil bore opens out on an inner circumferential surface of the bearing outer ring in order to feed the oil to the rolling elements and the raceways of the rolling element rows of the radial rolling bearing.

In particular, the at least one supply channel can be designed as a groove-like depression or as a flattened area in the outer jacket surface of the bearing outer ring. The groove-like depression or the flattening are incorporated into the outer circumferential surface of the bearing outer ring. Due to the arrangement on the outer jacket surface, different axial courses and cross-sectional shapes of the depressions or the flattened areas can be represented in a simple manner.

It is advantageous if the supply channel has a profile that rises in sections up to the axially directed end face. The section-wise rising course of the supply channel in the direction of the axially directed end face can be designed in a ramp-shaped or curved manner. The rising course allows the oil exiting the supply channel to be deflected in a targeted manner in the direction of the surrounding housing. As a result, part of the oil can initially reach the part of the housing to be cooled located above the bearing shaft before it reaches the bearing shaft and is thrown off by it.

According to a preferred embodiment, several supply channels via the Be arranged distributed circumference of the bearing outer ring. The supply channels can be evenly distributed in the circumferential direction of the bearing outer ring. An asymmetrical distribution of the supply channels in the circumferential direction of the bearing outer ring is also conceivable. This would create a focal point section at which the branched off partial oil flow predominantly emerges from the end face of the bearing outer ring. The course of at least one of the supply ducts, which rises in sections up to the axially directed end face, makes it possible to supply structurally more difficult-to-access sections in the interior of the housing directly with a proportionate oil flow for cooling.

The supply channels can preferably be arranged within an angular range of up to 180 °. The grouping of the supply channels can be concentrated in the upper area of the housing of the exhaust gas turbocharger. In this way, adequate cooling of the rotor shaft and the upper area of the housing can be achieved by a corresponding supply of oil.

Furthermore, a deflection element can be provided to deflect the oil flow emerging from the at least one supply channel. The emerging oil flow hits the deflection element and is thus deflected according to its inclination. The deflecting element can be designed as a disk, which is arranged adjacent to the end face of the bearing outer ring in the housing. In addition, in the areas where the oil reaches the rotor shaft, slinger rings can be arranged, which distribute the oil evenly on the inside of the housing.

Finally, the object is to be achieved by a radial roller bearing, in particular a multi-row radial roller bearing in an exhaust gas turbocharger, with at least one bearing outer ring. For this purpose, the at least one bearing outer ring is designed according to one of Claims 1 to 7. In particular, the radial roller bearing can be designed as a shoulder ball bearing or angular contact ball bearing.

The invention is not restricted to the specified combination of the features of the independent patent claims 1 and 8 with the patent claims dependent thereon. Furthermore, there are further possibilities for combining individual features with one another, in particular when they result from the patent claims, the following description of the exemplary embodiments or directly from the figures. In addition, the reference of the claims to the figures through the use of reference signs should in no way limit the scope of protection of the claims to the illustrated embodiment examples.

Figure list

• 1 eine schematische Darstellung eines Längsschnitts eines Abgasturboladers;
• 2 eine schematische Teilansicht eines Gehäuses des Abgasturboladers im Längsschnitt mit einer in diesem über ein Radialwälzlager gelagerten Läuferwelle;
• 3 eine Detailansicht III gemäß 2 mit einer nicht zur Erfindung gehörenden Ausführungsform eines Lageraußenrings;
• 4 eine nicht zur Erfindung gehörende Ausführungsform eines Lageraußenrings;
• 5 eine nicht zur Erfindung gehörende Ausführungsform eines Lageraußenrings;
• 6 eine erste erfindungsgemäße Ausführungsform eines Lageraußenrings;
• 7 eine zweite erfindungsgemäße Ausführungsform eines Lageraußenrings;
• 8 eine dritte erfindungsgemäße Ausführungsform eines Lageraußenrings; und
• 9 eine nicht zur Erfindung gehörende Ausführungsform eines Lageraußenrings.

To further explain the invention, reference is made to the drawings, in which different exemplary embodiments are shown in simplified form. Show it:

• 1 a schematic representation of a longitudinal section of an exhaust gas turbocharger;
• 2 a schematic partial view of a housing of the exhaust gas turbocharger in longitudinal section with a rotor shaft mounted therein via a radial roller bearing;
• 3 a detailed view III according to 2 with an embodiment of a bearing outer ring not belonging to the invention;
• 4th an embodiment not belonging to the invention of a bearing outer ring;
• 5 an embodiment not belonging to the invention of a bearing outer ring;
• 6th a first embodiment of the invention of a bearing outer ring;
• 7th a second embodiment of the invention of a bearing outer ring;
• 8th a third embodiment of the invention of a bearing outer ring; and
• 9 an embodiment not belonging to the invention of a bearing outer ring.

Detailed description of the drawing

1 shows a schematic representation of a longitudinal section of an exhaust gas turbocharger 1 with a partial view of a housing 2 . This is an arrangement according to the prior art. In the case 2 is a radial roller bearing 3 arranged by a runner 4th rotatable in the housing 2 is stored. The runner 4th includes a turbine wheel 5 and one by means of a screw connection 6th with the turbine wheel 5 connected rotor shaft 7th .

The radial roller bearing 3 is designed as a double row angular contact ball bearing and comprises an outer bearing ring 8th , the two partial rings in the illustrated embodiment 8a , 8b having. Between the two partial rings 8a and 8b is a spring element 9 arranged which the partial rings 8a and 8b resiliently holds in an axially spaced apart position. In the partial rings 8a and 8b is a row of rolling elements with in an annular cage 16 guided balls 15th arranged. To guide the respective row of rolling elements, the bearing outer ring 8th on its inner lateral surface 17th axially spaced outer raceways 18a , 18b on. On the section of the rotor shaft 7th on which the radial rolling bearing 3 is arranged, are located according to the arrangement of the raceways 18a , 18b axially spaced inner raceways 19a , 19b .

In the case 2 of the exhaust gas turbocharger 1 are oil feeds designed as bores 10 intended. The partial rings 8a , 8b of the bearing outer ring 8th each have an outer lateral surface 11a , 11b , on the at least one circumferential supply groove 12a , 12b is arranged. The oil feeds 10 in the case 2 open into the respective supply groove 12a or. 12b a. The partial rings 8a , 8b of the bearing outer ring 8th indicate the respective partial ring 8a or. 8b radially penetrating spray oil bores 13a , 13b on which, starting from the supply groove 12a or. 12b , on the inner lateral surface 17th of the two-part bearing outer ring 8th open between the rows of rolling bearings. By communicating with the oil supplies 10 connected splash oil holes 13a , 13b becomes the radial roller bearing 3 a supply oil flow is supplied. On the one hand, the supplied oil is used to lubricate the radial roller bearing 3 used. On the other hand, this can be done from the radial roller bearing 3 Oil escaping on both sides at the end between the rolling elements can be used to, among other things, the shaft section between the radial rolling bearing 3 and the turbine wheel 5 to cool.

Between the outer jacket surface 11a , 11b of the radial roller bearing 3 and the case 2 is an oil-supplied squeeze film gap to inhibit vibrations 14th educated. The one located in the annular squeeze film gap 14th The oil film that forms is referred to as a so-called squeeze film damper and serves to dampen vibrations. The oil supply to the squeeze film gap 14th takes place through the oil supplies 10 in the case 2 .

2 shows schematically a partial view of the housing on an enlarged scale 2 of the exhaust gas turbocharger 1 in longitudinal section. In the case 2 is the radial roller bearing designed as a double row angular contact ball bearing 3 arranged, which according to the illustrated embodiment in contrast to 1 a one-piece bearing outer ring 20th has, whereby the arrangement of a spring element between partial rings is omitted. The bearing outer ring 20th has an outer jacket surface 21a on that with the circumferential supply grooves 22a , 22b is provided. Through one in the case 2 provided oil supply 23 , of which two inclined holes 24 branch off, the on the outer surface 21a circumferentially arranged supply grooves 22a , 22b Oil supplied. From the supply grooves 22a , 22b starting, extend in the bearing outer ring 20th these radially penetrating spray oil bores 25a , 25b on an inner lateral surface 21b of the bearing outer ring 20th open between the rows of rolling bearings. The bearing outer ring 20th has on both sides end faces extending in sections in the radial direction 29a or. 29b on, with the radially outer area of the bearing outer ring 20th in installed position on radially inwardly extending projections 2a , 2 B on the housing 2 supports. In the bearing outer ring 20th are supply channels 26th , on their arrangement and training below in connection with the 3 is received.

3 shows a detailed view III according to 2 with a section of the bearing outer ring not designed according to the invention 20th . The bearing outer ring 20th is on its the turbine wheel 5 facing side with at least one supply channel 26th provided, which as coaxial to the longitudinal central axis 27 of the runner 4th arranged hole 28 is executed. The at least one supply channel 26th is with the supply groove 22b directly communicating connected. The at least one supply channel 26th opens at its the turbine wheel 5 facing face 29b of the bearing outer ring 20th out. Through the at least one supply channel 26th becomes a partial oil flow of the supply oil flow from the supply groove 22b branched off. The one from the at least one supply channel 26th on the face 29b escaping partial oil flow reaches the rotating rotor shaft 7th which the oil outwards towards the surrounding housing 2 hurled. In this way the section of the rotor shaft becomes 7th to which the turbine wheel 5 is connected as well as the surrounding section of the housing 2 an additional flow of oil is supplied to cool them. Through the targeted supply of the branched off partial oil flow to the rotating surface of the rotor shaft 7th are thrown against the force of gravity above the longitudinal center axis 27 lying areas of the housing 2 more oil supplied. This can be done in the circumferential direction of the bearing outer ring 20th distributes several supply channels 26th be provided.

4th shows a detailed view of a second embodiment of the bearing outer ring not belonging to the invention 20th . According to this second embodiment, the at least one is a supply channel 26th than one on the outer circumferential surface 21a provided groove-like recess 30th executed. The at least one groove-like depression 30th runs between the supply groove 22b and the face 29b . The at least one supply channel 26th is also taken directly from the supply groove 22b fed.

5 shows a detailed view of a third embodiment of the bearing outer ring not belonging to the invention 20th . According to this third embodiment, the at least one is a bore 28 Executed supply channel 26th through the splash oil hole 25b with the supply groove 22b directly communicating connected.

In 6th is a detailed view of a first embodiment of the bearing outer ring according to the invention 20th shown. This fourth embodiment of the bearing outer ring 20th differs from the preceding embodiments not according to the invention in that the at least one supply channel 26th not directly from the supply groove 22b is fed. That is, the at least one supply channel 26th is not in direct communication with the supply groove 22b by the supply channel 26th in the supply groove 22b joins. According to the fourth embodiment, it is axially spaced from the supply groove 22b an at least partially circumferential collecting groove 31 on the outer surface 21a intended. Between the collecting groove 31 and that of the turbine wheel 5 facing face 29b of the bearing outer ring 20th at least one extends as a groove-like depression 30th Executed supply channel 26th . Feeding the collecting groove 31 with oil takes place indirectly through the in the annular gap 33 between housing 2 and bearing outer ring 20th forming oil film that acts as a squeeze film damper.

In 7th FIG. 13 is a modification of the first embodiment of the invention according to FIG 6th shown. According to this modification, the at least one is a supply channel 26th that is the collecting groove 31 with the face 29b connects, as a hole 32 executed. Feeding the collecting groove 31 with oil takes place indirectly through the in the annular gap 33 between housing 2 and bearing outer ring 20th forming oil film.

In 8th is a detailed view of a third embodiment according to the invention. In this embodiment, to increase the oil flow into the collecting groove 31 an inlet designed as a groove 34 between the supply groove 22b and the collecting groove 31 provided, which extends in the axial direction on the outer circumferential surface 21a extends. The at least one supply channel 26th that is the collecting groove 31 with the face 29b connects is also called a hole 32 executed. The supply channel 26th can, as in 6th shown, also be designed as a groove.

In 9 is a detailed view of an embodiment not belonging to the invention. According to this embodiment, the supply channel 26th a profile 35 that rises in sections in the direction of the axially directed annular end face 26b. The course 35 can, as in 9 shown, be designed essentially ramp-shaped. A curved course of the supply channel is also conceivable 26th . That in the direction of the face 29b flowing oil is through the rising course 35 in the direction of the above the bearing shaft 7th Section of the housing 2 distracted.

List of reference symbols

1

Exhaust gas turbocharger

2

casing

2a

head Start

2 B

head Start

3

Radial roller bearings

4th

runner

5

Turbine wheel

6th

Screw connection

7th

Rotor shaft

8th

Bearing outer ring

8a

Partial ring

8b

Partial ring

9

Spring element

10

Oil supply

11a

Outer circumferential surface of 8a

11b

Outer circumferential surface of 8b

12a

Supply groove from 8a

12b

Supply groove from 8b

13a

Splash oil drilling from 8a

13b

Splash oil drilling from 8b

14th

Squeeze film gap

15th

Bullet

16

Cage

17th

Inner surface of 8th

18a

outer career of 8a

18b

outer career of 8b

19a

inner career of 8a

19b

inner career of 8b

20th

Bearing outer ring

21a

Outer circumferential surface of 20th

21b

Inner surface of 20th

22a

Supply groove from 20th

22b

Supply groove from 20th

23

Oil supply

24

drilling

25a

Splash oil drilling from 20th

25b

Splash oil drilling from 20th

26th

Supply channel

27

Longitudinal central axis

28

Through hole

29a

Face of 20th

29b

Face of 20th

30th

groove-like depression

31

Collecting groove

32

drilling

33

Annular gap

34

Intake

Claims (8)

Bearing outer ring (20) of a radial roller bearing (3) in an exhaust gas turbocharger (1), with an outer circumferential surface (21 a, 21b) on which at least one circumferential supply groove (22a, 22b) is arranged, with the outer circumferential surface (21a, 21b) of the Radial roller bearing (3) and a housing (2) accommodating the radial roller bearing, a squeeze film gap (14) that can be supplied with oil can be formed, as well as axially directed annular end faces (29a, 29b), the bearing outer ring (20) at least one in the supply channel (26) extending in the axial direction of the bearing outer ring (20), which can be fed indirectly by one of the supply grooves (22b), and wherein the at least one supply channel (26) emerges at an end face (29a, 29b) of the bearing outer ring (20), characterized in that between the supply groove (22b) and the end face (29b) a circumferential collecting groove (31) is arranged on the outer jacket surface (21a), which lubricates oil through the squeeze film gap (14 ) is supplied and which opens into the supply channel (26). Bearing outer ring (20) Claim 1 , characterized in that at least one spray oil bore (25b) penetrating the bearing outer ring (20) in a substantially radial direction is provided which opens into a supply channel (26) designed as a through bore (28). Bearing outer ring (20) Claim 1 , characterized in that the supply channel (26) is designed as a groove-like recess (30) in the outer jacket surface (21a) of the bearing outer ring (20). Bearing outer ring (20) Claim 1 , characterized in that the supply channel (26) is designed as a flattening on the outer jacket surface (21a) of the bearing outer ring (20). Bearing outer ring (20) Claim 1 , characterized in that the supply channel (26) has a section-wise rising course (35) up to the axially directed end face (29b). Bearing outer ring (20) Claim 1 , characterized in that several supply channels (26) are arranged distributed over the circumference of the bearing outer ring (20). Bearing outer ring (20) Claim 6 , characterized in that the supply channels (26) are arranged within an angular range of up to 180 °. Radial roller bearing (3), in particular multi-row radial roller bearing, of an exhaust gas turbocharger (1), with at least one bearing outer ring (20), characterized in that the at least one bearing outer ring (20) according to one of the Claims 1 to 7th is trained.

Images