DE102019210890A1 - Rolling bearing arrangement - Google Patents

Abstract

The invention relates to a roller bearing arrangement with at least one bearing outer ring extending around an axis of rotation, at least one bearing inner ring arranged inside the bearing outer ring and extending around the axis of rotation and a plurality of rolling elements arranged one behind the other in the circumferential direction around the axis of rotation, rolling on the bearing outer ring and the bearing inner ring, which are positioned in an annular space between the bearing outer ring and the bearing inner ring; with a housing in which the bearing outer ring is mounted in a film of squeezing oil, with an end face of the bearing outer ring and a wall of the housing directly facing each other in the direction of the axis of rotation. that the end face of the bearing outer ring and / or the wall of the housing is / are provided with grooves distributed over the circumference and / or a texture which has a flow cross section for guiding oil out of the squeezing oil film i n form / train the annulus.

Description

The present invention relates to a rolling bearing arrangement according to the preamble of claim 1. The present invention is particularly applicable for mounting a so-called fast rotating shaft, for example an exhaust gas turbine, a pump or a compressor, a turbocharger or an electric charger for charging an internal combustion engine, but also for mounting a Tool spindle or a rotor of a high-speed motor and suitable for use in other machines.

Rolling bearing arrangements of the generic type have an outer bearing ring, an inner bearing ring and rolling elements between the outer bearing ring and the inner bearing ring, the rolling elements rolling accordingly on radially inner raceways of the bearing outer ring and radially outer raceways of the bearing inner ring. The bearing outer ring is mounted in a housing by means of a squeeze oil film, the squeeze oil film serving to dampen the roller bearing arrangement. The housing encloses the bearing outer ring in such a way that an end face of the bearing outer ring and a wall of the housing are directly opposite one another in the direction of the axis of rotation. Conventionally, the surface of the end face and the wall is made particularly flat with a very high surface quality. The play in the axial direction, that is to say in the direction of the axis of rotation, between the end face and the wall is designed to be very small in order, for example, to avoid undesired displacement of the bearing outer ring in the housing due to alternating thrust directions. Thus, through a remaining gap between the end face and the wall, hardly any oil from the squeeze oil film can get into an annular space with the rolling elements.

In the case of a roller bearing arrangement, for example in a turbocharger, large amounts of heat can be introduced into the roller bearing arrangement, which can lead to damage, for example due to jamming. In order to avoid impermissibly high temperatures in such applications, for example in the area of the bearing inner ring or the rolling elements, oil from the squeeze oil film is fed into this area in order to cool the area with a corresponding oil flow. For this purpose, cooling channels are introduced in the housing or in the bearing outer ring, which is complex and increases the manufacturing costs of the roller bearing arrangement.

The present invention is therefore based on the object of improving a rolling bearing arrangement of the type shown in such a way that a temperature-endangered area within the bearing outer ring can be cooled by a specifically adjustable oil flow from the squeezing oil film without the need to make additional bores in the bearing outer ring or in the housing .

The object according to the invention is achieved by a roller bearing arrangement having the features of claim 1. The dependent claims describe advantageous and particularly expedient configurations of the invention, as well as an exhaust-gas turbine bearing and a pump or compressor bearing with a roller bearing arrangement according to the invention.

The roller bearing arrangement according to the invention comprises at least one bearing outer ring extending around an axis of rotation and at least one bearing inner ring arranged within the bearing outer ring and extending around the axis of rotation. A plurality of bearing outer rings and / or bearing inner rings positioned next to one another in the direction of the axis of rotation can also be provided.

Furthermore, a plurality of rolling elements arranged one behind the other in the circumferential direction around the axis of rotation and rolling on the bearing outer ring and the bearing inner ring are provided, which are arranged in an annular space between the bearing outer ring and the bearing inner ring. The roller bearing arrangement is designed, for example, as a radial or axial-radial roller bearing arrangement, so that it absorbs radial forces or axial-radial forces accordingly.

For example, the roller bearing arrangement has two rows of roller bearings positioned at a distance from one another in the direction of the axis of rotation, wherein the rows can be designed as a single row or also as a double row or multiple row. Other arrangements are possible.

According to the invention, a housing is provided which is made in one piece or, as a rule, in several parts. For example, the housing has a base body and a housing cover mounted on this.

The bearing outer ring is supported in the housing in a film of squeezing oil in such a way that an end face of the bearing outer ring and a wall of the housing are directly opposite one another in the direction of the axis of rotation. The wall of the housing can be formed by an axial collar in the base body of the housing or by a component inserted in or mounted on the housing.

According to the invention, the end face of the bearing outer ring is provided with grooves distributed over the circumference and / or with a texture which forms / forms a flow cross section for guiding oil from the squeeze oil film into the annular space. Additionally or alternatively, the Wall of the housing can be provided with corresponding grooves and / or with a corresponding texture.

As a result of the invention, the flow cross-section for a cooling oil flow is at least enlarged along the end face of the bearing outer ring, without the axial play being enlarged. Furthermore, the design according to the invention has a favorable effect with regard to undesired excitation of the roller bearing arrangement through vibrations.

With the invention, the amount of oil fed into the end face of the annular space can be adjusted very precisely and an undesirably large oil flow, which can lead to splashing losses, loss of efficiency and wear, is avoided. Furthermore, by designing the grooves and / or the texture, damping of the bearing outer ring in the axial direction can be set in a targeted manner.

According to one embodiment of the invention, the grooves extend obliquely to the radial direction in relation to the axis of rotation or the bearing rings. Correspondingly, the texture can also have channels running obliquely to the radial direction.

Alternatively, the grooves or the channels extend in the radial direction, in particular exclusively in the radial direction.

A combination of the two aforementioned embodiments is possible, accordingly in the form of grooves or channels running obliquely to the radial direction and in the radial direction.

According to one embodiment of the invention, the grooves and / or the texture, that is to say their channels, form a cross pattern.

Texture in the sense of the present invention means any surface design which has channels between comparatively raised areas in the end face of the bearing outer ring and / or in the wall, so that oil can flow through these channels from radially outside to radially inside and, if necessary, also in the circumferential direction. The texture can, for example, be introduced into the end face and / or the wall by embossing. However, machining is also possible, for example milling. It is also possible to apply the texture by scraping or scratching. According to one embodiment of the invention, the texture is introduced by means of a laser. However, other methods are also possible.

In cross section, the grooves and / or the channels of the texture can, for example, have a rectangular, V-shaped or at least partially round shape, in each case viewed in the direction of flow of the oil through the corresponding groove / channel. Other cross-sectional shapes are possible, a trapezoidal shape and a polygonal shape, a T-shape and a polygonal shape are only mentioned as examples. Combinations of grooves and / or channels with different cross-sections are also possible. In the case of a rectangular shape, the groove walls or channel walls are perpendicular to a groove base or channel base. In the case of a V shape, they extend obliquely to this and in the case of a round shape, in particular the channel base or groove base or the transition to the walls is rounded in cross section.

The depth of the grooves and / or the channels formed by the texture is preferably in the range between 0.02 mm and 2 mm. All the grooves and / or channels can have the same depth or different depths can be provided.

For example, starting from a flat end face, the face is reduced by 5% to 25% by introducing the texture. Thus, the area of the texture can preferably be up to a third of the remaining front area.

According to one embodiment of the invention, the texture has a surface quality of Ra 0.4-12.5 μm. The surface quality is also referred to as roughness, Ra as mean roughness value.

The bearing inner ring preferably rotates around the axis of rotation and the bearing outer ring is secured against rotating in the housing. For this purpose, an anti-rotation device can be provided, for example in the form of a screw or a bolt, which is inserted radially into a bore in the bearing outer ring and anchored in the housing.

According to a particular embodiment of the invention, the bearing outer ring has two end faces facing away from one another at its two axial ends, only one of which is provided with the grooves and / or the texture. The other end face can accordingly be made flat or smooth.

According to another embodiment, both end faces are provided with grooves and / or a texture, the depth of the grooves and / or texture on the first end face then preferably being greater than a corresponding depth of the grooves and / or texture on the second end face. This ensures that more oil flows along the first end face than along the second end face, so that the first end face is preferably assigned to the axial end region of the bearing outer ring into which comparatively more heat is introduced during operation of the roller bearing arrangement. For example, a turbine wheel to which hot exhaust gas is applied can be provided in the area of this axial end.

Of course, in addition or as an alternative, corresponding grooves and / or a texture can also be provided in one or the two walls opposite the end faces of the bearing outer ring, preferably with a correspondingly different depth. It is also possible for only one of the two corresponding walls to be provided with corresponding grooves or a corresponding texture.

At least one oil supply is advantageously provided in the housing, which opens into the squeeze oil film in the direction of the axis of rotation between the two end faces. Furthermore, at least one oil discharge can be provided, which preferably also opens out in the direction of the axis of rotation between the two end faces. The oil discharge can in particular comprise a radial bore in the bearing outer ring.

As stated at the outset, the present invention can be used in various applications, in particular for supporting a rapidly rotating shaft. The roller bearing arrangement is particularly preferably used for mounting a shaft in an exhaust gas energy utilization system such as a turbocharger or a turbo compound turbine or also an electrical machine such as an electrical turbocharger or e-booster. However, the invention can also be used for mounting tool spindles, the rotors of motors, in particular electric motors, or for mounting other rotating components.

An exhaust gas turbine bearing is preferably designed with a shaft that carries a turbine wheel in the area of one axial end and carries, for example, a pinion, an electrical machine, a pump wheel or a compressor wheel in the area of the other axial end. The shaft is then preferably mounted with the roller bearing arrangement according to the invention in such a way that the grooves and / or the texture is provided in the end face at least at the axial end of the bearing outer ring, which is assigned to the turbine wheel, with a flat opposite end face, or the grooves and / or the texture at this end is / is executed with a comparatively greater depth than at the other end.

• - eine vorgegebene Dämpfung (weicher/härter) in der Axialrichtung, das heißt in Richtung der Drehachse;
• - eine vorgegebene Wärmeabfuhr in einem bestimmten Bereich;
• - eine gewünschte Kühlung der benachbart zu der Stirnseite angeordneten Wälzlager durch eine Ölzufuhr axial von außen.

Due to the flow cross-section made available by the grooves and / or the texture, the invention allows the amount of oil that flows off along the end face to be set, preferably as a function of at least one of the following parameters:

• - a predetermined damping (softer / harder) in the axial direction, that is, in the direction of the axis of rotation;
• - a predetermined heat dissipation in a certain area;
• - A desired cooling of the roller bearings arranged adjacent to the end face by means of an oil supply axially from the outside.

The invention is to be described below by way of example with the aid of exemplary embodiments and the figures.

• 1 ein Ausführungsbeispiel einer erfindungsgemäßen Wälzlageranordnung in einer Abgasturbinenlagerung;
• 2-4 schematische Darstellungen von Lageraußenringen mit stirnseitigen Nuten oder einer Textur.

Show it:

• 1 an embodiment of a roller bearing arrangement according to the invention in an exhaust gas turbine bearing;
• 2-4 schematic representations of bearing outer rings with grooves on the face or a texture.

In the 1 an embodiment of the invention is shown in the form of an exhaust turbine bearing. The exhaust turbine bearing includes a shaft 10 around an axis of rotation 1 all around in a bearing inner ring 3 is mounted and at the first axial end 10.1 a turbine wheel 11 carried by the wave 10 is arranged. At the second axial end of the shaft 10 is for example a compressor wheel 12th or a pinion or the like carried by the shaft 10 arranged.

In the embodiment shown, the bearing inner ring is 3 designed in several parts, comprising several, preferably two, in the direction of the axis of rotation 1 parts provided side by side. However, it could also be made in one piece.

The bearing inner ring 3 can be rotated around the axis of rotation 1 in a stationary bearing outer ring 2 stored. The bearing inner ring 3 and the bearing outer ring 2 have raceways on which in the annulus 5 between the bearing inner ring 3 and the bearing outer ring 2 positioned rolling elements 4th roll off. The rolling elements 4th are designed, for example, as balls or as cones or cylinders. In the embodiment shown, the bearing outer ring is in the area of both axial ends 2 or the bearing inner ring 3 a number of rolling elements each 4th in the corresponding annulus 5 provided, each held by a cage. However, this is not mandatory.

The bearing outer ring 2 , which is in one piece in the embodiment shown, but could also be designed in several parts, for example analogous to the bearing inner ring shown 3 , is about one Pinch oil film 7th in the housing 6 stored. The squeeze oil film 7th dampens vibrations of the bearing outer ring 2 .

The case 6 has an oil supply 13 on what oil is in the oil film 7th can be directed. Diametrically opposite to the oil supply 13 is an oil drain 14th provided here a radial hole 15th in the bearing outer ring and a radial bore preferably aligned with this 16 in the housing 6 having.

About oil from the squeeze oil film 7th in the area between the bearing inner ring 3 and the bearing outer ring 2 to direct can drilling 17th in the bearing outer ring 2 be provided, which is preferably in the axial center between the rows of rolling elements 4th are positioned. Thus, most of this can come from the oil supply 13 for oil drainage 14th flowing oil axially in the middle between the rolling elements 4th flow, preferably without the rolling elements 4th to apply or only with a slight application of the rolling elements 4th . These holes 17th are not mandatory, however, they could also be saved.

The bearing outer ring 2 has two end faces at its two axial ends 2.1 and 2.2 on, namely the face 2.1 on the turbine wheel 11 associated axial end and the end face 2.2 at the opposite axial end. The respective face 2.1 , 2.2 of the bearing outer ring 2 stands a wall 6.1 of the main body of the housing or a wall 18.1 a housing cover 18th axially directly opposite. The game between the respective wall 6.1 , 18.1 and the face 2.1 , 2.2 is comparatively low to prevent the bearing outer ring from swinging 2 in the axial direction, that is, in the direction of the axis of rotation 1 , to prevent. To still have an oil flow from the squeeze oil film 7th in the annulus 5 To ensure at the comparatively hotter end of the roller bearing arrangement is the first end face 2.1 with grooves 8th or a texture 9 how to use the 4th will be explained by way of example. Through these grooves 8th respectively channels 9.1 the texture 9 (see the 4th ) can oil from the squeeze oil film 7th in the annulus 5 flow and over the rolling elements 4th or in the radial direction in the direction of the oil discharge 14th flow away and thereby remove heat.

The shape of the grooves 8th or their cross-section can be determined depending on the desired flow cross-section for the oil flow. For example, the 2 Grooves 8th that have a round cross-sectional shape or a round groove base. The 3 shows grooves 8th in the face 2.1 of the bearing outer ring 2 , which have a rectangular cross-section, here with a flat groove base, as well as grooves 8th with a triangular cross-section. The 4th shows a texture 9 with channels 9.1 in the face 2.1 of the bearing outer ring, this texture 9 provides the desired flow cross-section for the oil.

In the design according to 1 is the face 2.2 at the comparatively colder axial end of the bearing outer ring 2 Smooth or flat, that is, free of grooves and texture. However, this could also be different. The one along the end face is preferred 2.1 for the oil from the squeeze oil film 7th However, the flow cross section provided is larger than a corresponding one along the end face 2.2 available flow cross-section. This can be achieved both by a corresponding cross section and by a corresponding number of grooves or channels.

List of reference symbols

1

Axis of rotation

2

Bearing outer ring

2.1

Face

2.2

Face

3

Bearing inner ring

4th

Rolling elements

5

Annulus

6th

casing

6.1

wall

7th

Pinch oil film

8th

Groove

9

texture

9.1

channel

10

wave

10.1

first axial end

10.2

second axial end

11

Turbine wheel

12

Compressor wheel

13

Oil supply

14th

Oil drainage

15th

Radial bore

16

Radial bore

17th

drilling

18th

Housing cover

18.1

wall

Claims (16)

Rolling bearing arrangement with at least one bearing outer ring (2) extending around an axis of rotation (1), at least one inner bearing ring (3) arranged inside the outer bearing ring (2) and extending around the axis of rotation (1) and a plurality of inner bearing ring (3) in the circumferential direction around the axis of rotation (1 ) one behind the other, rolling elements (4) rolling on the bearing outer ring (2) and the bearing inner ring (3), which are positioned in an annular space (5) between the bearing outer ring (2) and the bearing inner ring (3); with a housing (6) in which the bearing outer ring (2) is mounted in a squeeze oil film (7), with an end face (2.1) of the bearing outer ring (2) and a wall (6.1) of the housing (6) in the direction of the axis of rotation (1) are directly opposite; characterized in that the end face (2.1) of the bearing outer ring (2) and / or the wall (6.1) of the housing (6) is / are provided with grooves (8) distributed over the circumference and / or a texture (9), which form a flow cross-section for guiding oil from the squeeze oil film (7) into the annular space (5). Rolling bearing arrangement according to Claim 1 , characterized in that the grooves (8) extend obliquely to the radial direction and / or the texture (9) has channels (9.1) extending obliquely to the radial direction. Rolling bearing arrangement according to one of the Claims 1 or 2 , characterized in that the grooves (8) extend in the radial direction and / or the texture (9) has channels (9.1) extending in the radial direction. Rolling bearing arrangement according to one of the Claims 1 to 3 , characterized in that the grooves (8) and / or the texture (9) form a cross pattern. Rolling bearing arrangement according to one of the Claims 1 to 4th , characterized in that the grooves (8) and / or channels (9.1) of the texture (9) have a rectangular, V-shaped or at least partially round cross-section, viewed in the direction of flow of the oil. Rolling bearing arrangement according to one of the Claims 1 to 5 , characterized in that a depth of the grooves (8) and / or of channels (9.1) formed by the texture (9) is in the range between 0.02 mm to 2 mm. Rolling bearing arrangement according to one of the Claims 1 to 6 , characterized in that the texture (9) has a surface quality of Ra 0.4 to 12.5 µm. Rolling bearing arrangement according to one of the Claims 1 to 7th , characterized in that the inner bearing ring (3) rotates around the axis of rotation (1) and the outer bearing ring (2) is secured against rotating in the housing (6). Rolling bearing arrangement according to one of the Claims 1 to 8th , characterized in that the bearing outer ring (2) has two opposite end faces (2.1, 2.2) at its two axial ends, only one of which is provided with the grooves (8) and / or the texture (9). Rolling bearing arrangement according to one of the Claims 1 to 8th , characterized in that the bearing outer ring (2) has two opposite end faces (2.1, 2.2) at its two axial ends, both of which are provided with grooves (8) and / or a texture (9). Rolling bearing arrangement according to Claim 10 , characterized in that a depth of the grooves (8) and / or of channels (9.1) of the texture (9) on the first end face (2.1) is greater than a corresponding depth of the grooves (8) and / or of channels (9.1 ) the texture (9) on the second face (2.2). Rolling bearing arrangement according to one of the Claims 9 to 11 , characterized in that at least one oil supply (13) is provided in the housing (6) which opens into the squeeze oil film (7) in the direction of the axis of rotation (1) between the two end faces (2.1, 2.2), and furthermore at least one oil discharge (14 ) is also provided in the direction of the axis of rotation (1) between the two end faces (2.1, 2.2). Rolling bearing arrangement according to Claim 12 , characterized in that the oil discharge (14) comprises at least one radial bore (15) in the bearing outer ring (2). Exhaust-gas turbine bearing with a shaft (10) which carries a turbine wheel (11) in the area of one axial end, characterized in that the shaft (10) with a roller bearing arrangement according to one of the Claims 1 to 13 is stored. Pump or compressor bearing with a shaft (10) which carries a pump wheel or compressor wheel (12) in the area of one axial end, characterized in that the shaft (10) with a roller bearing arrangement according to one of the Claims 1 to 13 is stored. Pump or compressor mounting according to Claim 15 , characterized in that the shaft (10) carries a drive wheel, in particular a turbine wheel (11), in the region of its other axial end.

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