DE102013021636A1 - Bearing cage for a rolling bearing - Google Patents

Abstract

The invention relates to a bearing cage (10) for a roller bearing, comprising a plurality of pockets separated by respective webs (18) for receiving rolling elements (16) of the roller bearing, and having at least one axial support surface (20), via which the bearing cage (20). 10) can be supported in the axial direction on a corresponding component, wherein the axial support surface (20) has at least one hydrodynamically effective mold surface (24).

Description

The invention relates to a bearing cage for a rolling bearing according to the preamble of patent claim 1.

Such a bearing cage for a rolling bearing is for example the DE 10 2011 088 690 A1 to be known as known. The roller bearing cage has a plurality of pockets, which are separated from each other in the circumferential direction of the rolling bearing by means of respective webs. This means that the respective webs are arranged in the circumferential direction between the respective pockets. The pockets serve to accommodate rolling elements of the bearing. In recorded in the pockets state of the rolling elements protrude in the radial direction on both sides a piece out of the pockets, so that therefore the rolling elements project beyond the bearing cage in the radial direction on both sides. As a result, the rolling elements can roll on respective, outside and inside raceways. The bearing cage serves in particular to guide the rolling elements and to keep at a mutual distance.

In addition, the bearing cage has at least one axial support surface, via which the bearing cage can be supported in the axial direction on a corresponding component. The axial support surface is usually also referred to as "axial bearing surface" or as "axial contact surface", since the bearing cage on the axial support surface in the axial direction in support system with the corresponding component and thus can start on the component. Thus, the bearing cage can be axially supported over the axial support surface.

The DE 10 2011 101 334 A1 discloses a connecting rod for an internal combustion engine of a motor vehicle, with a connecting rod bearing for a bearing on a crankshaft. The conrod bearing has at least one axial bearing surface for axial bearing. It is provided that the axial bearing surface of the conrod bearing has at least one, different from a phase, hydrodynamically effective molding surface.

It has been found that high forces, that is, axial forces can act on the bearing cage, in particular in its axial bearing, that is on the axial support surface, which - if no appropriate countermeasures are taken - can lead to high wear of the bearing cage.

Object of the present invention is therefore to develop a bearing cage of the type mentioned in such a way that the wear of the bearing cage can be kept very low.

This object is achieved by a bearing cage with the features of patent claim 1. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the remaining claims.

In order to further develop a bearing cage specified in the preamble of claim 1 species such that the wear of the bearing cage can be kept particularly low, it is inventively provided that the axial support surface has at least one hydrodynamically effective molding surface. It is preferably provided that the hydrodynamically effective shaping surface is a hydrodynamically effective shaping surface that is different from a chamfer. A "chamfer" is to be understood as a chamfer having at least an angle of 10 degrees between an axially perpendicular wall of a groove and a chamfered surface, and a height in the axial direction from a lower end of the chamfered surface up to an upper end of the tapered surface is measured, of at least 0.4 millimeters.

A "hydrodynamically effective shaping surface" should be understood in particular to mean a surface which is intended to actively build up a lubricating film of lubricant, in particular lubricating oil. By means of the hydrodynamically active shaping surface, a hydrodynamic lubricating film can be actively constructed on the axial support surface, in particular in the axial direction between the axial support surface and the corresponding component, so that the bearing cage is supported in the axial direction on the corresponding component in a particularly low-wear manner via the hydrodynamic lubricant film and can rotate relative to the corresponding component. As a result, the bearing cage can be stored axially particularly wear and low friction.

The invention is based on the idea that on a conventional bearing cage of a rolling bearing, which is also referred to as a "roller bearing", can occur by restricting the rolling elements acting on the bearing cage axial forces. This usually ensures a very high wear of the axial support surface of the bearing cage. In addition, this can lead to increased wear of a corresponding with the axial support surface of the bearing cage, axial support surface of the corresponding component. This results in a high friction loss.

This problem can be avoided by means of the bearing cage according to the invention, since by means of the hydrodynamically active mold surface active a friction and thus wear-reducing Lubricating film between the axial support surfaces can be actively built.

In a particularly advantageous embodiment of the invention, the bearing cage is made of a fiber-reinforced plastic, in particular of a glass fiber reinforced plastic. As a result, the wear of the bearing cage can be kept particularly low. In addition, by the active building up of the lubricating film, that is to say by the hydrodynamically effective forming surface, the danger can be kept particularly low that fibers of the fiber-reinforced plastic are exposed by axial wear, which could then have an abrasive and thus wear-increasing effect. In other words, by actively building the hydrodynamic lubricating film, it is possible to prevent the exposure of the fibers and their resulting abrasive action.

Overall, it is thus possible by means of the hydrodynamically effective mold surface to support axial forces occurring without solid contact of the axial support surfaces at least substantially wear-free and low-friction and to prevent exposure of the abrasive fibers, in particular glass fibers.

The bearing cage according to the invention can be used particularly advantageously in an internal combustion engine of a motor vehicle. The internal combustion engine is designed, for example, as a reciprocating internal combustion engine and comprises an output shaft in the form of a crankshaft, which can be mounted on the rolling bearing at least one corresponding bearing element friction and low-wear. The crankshaft is, for example, the aforementioned, corresponding to the bearing cage component, on which the bearing cage can start over its axial support surface. This means that both the wear of the bearing cage and the wear of the crankshaft can be kept low by means of the hydrodynamically effective mold surface. As a result, a low-wear operation of the internal combustion engine is overall representable.

It has proven to be particularly advantageous if the hydrodynamically effective shaping surface is designed as a ramp, in particular as a ramp rising in the circumferential direction of the bearing cage.

Alternatively or additionally, it is possible that the hydrodynamically effective forming surface is formed as a waviness of the axial support surface. In this case, the hydrodynamically active shaping surface can comprise, for example, at least one wave trough and / or at least one wave crest of the waviness.

Another embodiment is characterized in that the largest pitch of the hydrodynamically effective forming surface is less than 2 degrees. Preferably, it is provided that the largest slope of the hydrodynamically effective mold surface is 0.1 degrees.

A further embodiment is characterized in that at least two hydrodynamically effective shaping surfaces are provided identically in both directions of rotation of the bearing cage or the roller bearing, whereby, for example, a particularly simple assembly can be represented. This means that a first of the hydrodynamically active shaping surfaces is hydrodynamically effective in a first direction of rotation, wherein the second hydrodynamically active forming surface is hydrodynamically effective in a second direction of rotation opposite to the first direction of rotation. In this way, in particular a mounting installation insensitive mounting can be realized, as by means of the first mold surface, a hydrodynamic lubricating film is constructed when the bearing cage is rotated, for example during operation of the internal combustion engine in the first direction of rotation, wherein by means of the second mold surface, a hydrodynamic lubricating film can be constructed, if the Lagerkäfig is rotated, for example, during operation of the internal combustion engine in the second direction of rotation.

It has proven to be particularly advantageous if the axial support surface has at least six hydrodynamically effective shaping surfaces. If the bearing cage comprises, for example, two cage parts or two cage halves, it is preferably provided that the cage parts each have at least three hydrodynamically effective shaping surfaces.

As further particularly advantageous, it has been shown, if at least one at least substantially flat locking surface connects to the hydrodynamically effective mold surface, in particular in the circumferential direction of the bearing cage. This is particularly advantageous when the hydrodynamically effective molding surface is designed as a ramp. An adjoining the ramp locking surface, for example, between peaks is advantageous to avoid sharp edges and short-term operation without sufficient lubricant, for example, at a start of the internal combustion engine after a long service life, hedge.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and feature combinations mentioned above in the description as well as those mentioned below in the figure description and / or in the Figures alone features and feature combinations shown are not only in the particular combination specified, but also in other combinations or alone, without departing from the scope of the invention.

The drawing shows in:

1 a schematic perspective view of a bearing cage for a rolling bearing, which has at least one axial support surface having at least one hydrodynamically effective forming surface; and

2 a schematic side view of the hydrodynamically effective molding surface

1 shows in a schematic perspective view of a whole 10 designated bearing cage for a rolling bearing. The rolling bearing is used for example for storing, that is rolling bearings of an output shaft in the form of a crankshaft of an internal combustion engine of a motor vehicle. The crankshaft is mounted by means of the rolling bearing on a crankcase of the internal combustion engine designed as a reciprocating internal combustion engine, wherein the crankshaft is rotatable about an axis of rotation relative to the crankcase. As a result, a roller bearing of the crankshaft is created, so that the crankshaft is mounted particularly wear and low friction on the crankcase. As a result, a particularly efficient and thus fuel consumption and low-emission operation of the internal combustion engine can be represented.

The rolling bearing comprises a plurality of in 1 Rolling elements not shown. If the crankshaft is rotated about its axis of rotation relative to the crankcase, the rolling elements roll on an outer peripheral side track assigned to the crankshaft and on an inner peripheral side track assigned to the crankcase.

Out 1 it can be seen that the bearing cage two in the axial direction of the bearing cage 10 and thus the rolling elements juxtaposed rows 12 and 14 with respective bags 16 having. The respective bags 16 are in the circumferential direction of the bearing cage 10 by means of respective webs 18 separated from each other. How out 1 is recognizable, are the respective webs 18 in the circumferential direction between the respective pockets 16 arranged.

The bags 16 serve to receive the respective rolling elements. Im in the pockets 16 arranged or received state protrude the rolling elements in the radial direction on both sides of the pockets 16 out. This means that the rolling elements the bearing cage 10 protrude in the radial direction outwards and in the radial direction inwards, so that the rolling elements can roll on a rotation of the crankshaft about its axis of rotation on the respective raceways. The camp cage 10 serves to guide the rolling elements. In addition, the rolling elements by means of the bearing cage 10 kept at a distance to each other.

The camp cage 10 is made of a fiber-reinforced plastic in the form of a glass fiber reinforced plastic. The glass fiber reinforced plastic comprises a matrix of plastic in which reinforcing fibers are embedded in the form of glass fibers. The formed from a fiber-reinforced plastic bearing cage 10 For example, is produced by means of an injection molding in a tool as a tool falling precast.

In addition, the bearing cage points 10 at least one axial support surface 20 on, which is also referred to as "axial bearing surface". The camp cage 10 may alternatively or additionally a in 1 unrecognizable, second axial support surface, in the axial direction of the axial support surface 20 turned away.

Over the axial support surface 20 is the camp cage 10 in the axial direction on a corresponding component, for example, the crankshaft, supported, so that thereby the bearing cage 10 is mounted in the axial direction on the corresponding component. In other words, the bearing cage 10 over the axial support surface 20 start at the corresponding component, wherein the bearing cage 10 can rotate about the axis of rotation of the crankshaft relative to the corresponding component.

Out 1 it can be seen that the axial support surface 20 a plurality of circumferentially of the bearing cage 10 spaced apart grooves 22 which extend in the radial direction and serve, for example, for guiding lubricant in the form of lubricating oil.

In synopsis with 2 It can also be seen that the axial support surface 20 a plurality of hydrodynamically effective shaping surfaces 24 and 26 having, which in the circumferential direction of the bearing cage 10 connect to each other.

Out 2 It can be seen that the hydrodynamically effective shaping surfaces 24 and 26 are formed as ramps increasing in the circumferential direction. This increases the hydrodynamically effective mold surface 24 in a first direction of rotation, wherein the hydrodynamically effective molding surface 26 rises in a first direction of rotation opposite, second direction of rotation. This means that the molding surface 24 hydrodynamic in the first direction of rotation is effective, the molding surface 26 is hydrodynamically effective in the second direction of rotation.

Alternatively, the hydrodynamically effective molding surfaces 24 and 26 by a waviness of the axial support surface 20 be formed and accordingly each comprise at least one wave crest and a wave trough the ripple. By means of the tool in which the bearing cage 10 is produced, a very small ramp angle or a very flat waviness can be represented, the bearing cage 10 after its preparation also without further finishing.

Preferably, it is provided that the ramp angle or the largest pitch of the waviness is less than 2 degrees. Preferably, the ramp angle or the maximum pitch of the waviness is at least substantially 0.1 degrees, to thereby achieve a particularly good functionality with regard to an active structure of a lubricating film. Out 2 It can also be seen that the hydrodynamically effective shaping surfaces 24 . 26 are formed as different from a phase hydrodynamically effective molding surfaces. The hydrodynamically effective shaping surfaces 24 . 26 serve to lubricate a film of lubricant, in particular lubricating oil, between the axial support surface 20 and the corresponding component actively build, thereby the friction and wear of the bearing cage 10 particularly low.

Preferably, it is provided that at least three ramps or ripples are provided in the circumferential direction, that is to say over the circumference, for a statically determined system situation. Due to the provision of the hydrodynamically effective shaping surfaces 24 and 26 is a shape illustrating a hydrodynamic lubricating film structure on the axial support surface 20 of the bearing cage 10 realized.

In 2 is by a double arrow 28 the circumferentially extending extent of the hydrodynamically effective molding surface 24 illustrated. By a directional arrow 30 is in 2 the extension of a circumferential direction of the hydrodynamically effective molding surface 24 subsequent catch surface 32 illustrated. Also on the hydrodynamically effective mold surface 26 closes in the circumferential direction a locking surface 34 at. The locking surfaces 32 and 34 are particularly intended, in a state in which a small amount of lubricant on the axial support surface 20 is provided, for example, to ensure a safe axial storage shortly after a start of the internal combustion engine. In particular, it is possible by providing the locking surfaces 32 and 34 To avoid sharp edges and thus to ensure short-term operation without sufficient lubricant.

LIST OF REFERENCE NUMBERS

10

bearing cage

12

line

14

line

16

bag

18

web

20

axial support surface

22

groove

24

hydrodynamically effective mold surface

26

hydrodynamically effective mold surface

28

double arrow

30

arrow

32

Rest area

34

Rest area

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

• DE 102011088690 A1 [0002]
• DE 102011101334 A1 [0004]

Claims (6)

Bearing cage ( 10 ) for a rolling bearing, with a plurality of means of respective webs ( 18 ) separate pockets for receiving rolling elements ( 16 ) of the rolling bearing, and with at least one axial support surface ( 20 ), over which the bearing cage ( 10 ) can be supported in the axial direction on a corresponding component, characterized in that the axial support surface ( 20 ) at least one hydrodynamically effective molding surface ( 24 ) having. Bearing cage ( 10 ) according to claim 1, characterized in that the bearing cage ( 10 ) is formed of a fiber-reinforced plastic, in particular of a glass fiber reinforced plastic. Bearing cage ( 10 ) according to one of claims 1 or 2, characterized in that the hydrodynamically effective molding surface ( 24 ) as a ramp, in particular one in the circumferential direction of the bearing cage ( 10 ) Ramp rising, is formed. Bearing cage ( 10 ) according to any one of the preceding claims, characterized in that the hydrodynamically effective molding surface ( 24 ) is formed as a ripple of the axial support surface. Bearing cage ( 10 ) according to any one of the preceding claims, characterized in that the largest pitch of the hydrodynamically effective molding surface ( 24 ) is less than 2 degrees. Bearing cage ( 10 ) according to claim 5, characterized in that the largest slope of the hydrodynamically effective molding surface ( 24 ) Is 0.1 degrees.

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