WO2010045933A1

WO2010045933A1 - Roller bearing cage

Info

Publication number: WO2010045933A1
Application number: PCT/DE2009/001466
Authority: WO
Inventors: Rudolf Zeidlhack
Original assignee: Schaeffler Technologies Gmbh & Co. Kg
Priority date: 2008-10-25
Filing date: 2009-10-20
Publication date: 2010-04-29
Also published as: DE102008053248A1

Abstract

The invention relates to a roller bearing cage comprising two peripheral sections (2, 3) extending in the peripheral direction (U), each of which having an inner side (5, 6) facing the rolling bodies (4), and connecting sections (11, 12) extending between the peripheral sections (2, 3) and forming pockets (21) with the latter for receiving the rolling bodies (4). According to the invention, the roller bearing cage is axially guided on the inner side (5, 6) of at least one peripheral section (2, 3) by frontal abutment of the rolling bodies (4). In order to create a roller bearing cage that ensures a reliable and undisturbed lubricant supply in critical areas of the front surfaces of the roller bearing, the invention provides that each inner side (5, 6) has a recess (40, 41, 42, 43) towards the connecting sections (11, 12).

Description

Name of the invention

Rolling bearing cage

description

Field of the invention

The invention relates to a roller bearing cage with two circumferentially extending circumferential webs, each having a rolling bodies facing the inside, and with connecting webs extending between the peripheral webs and form with these pockets for receiving the rolling elements, wherein the roller bearing cage by frontal contact of the rolling elements is guided axially on the inside of at least one peripheral ridge.

Cages for rolling bearings are known in many forms and have proven to guide the rolling elements in the pockets provided by them. Especially with large rolling bearings (with a pitch circle diameter of more than 500 mm) increasingly cages composed of individual cage segments cages are used, which are made of weight saving reasons preferably made of plastics such as PEEK (polyether ether ketone). However, the present invention is generally suitable for rolling bearing cages without being limited to approximately composed of cage segments rolling bearing cages. Although the invention is particularly advantageous for cages for slewing bearings with multiple rows of rolling elements - such as two-row tapered roller bearings - can be used, it is also not limited in this respect but basically applicable to all types of bearings.

A roller bearing cage of the aforementioned type is known from German Offenlegungsschrift DE 102006 022951 A1, which describes a cage segment for a cage of a rolling bearing with at least two circumferentially extending circumferential webs - also referred to as longitudinal webs - and at least two connecting webs (transverse webs). The connecting webs form, with the respective section of the circumferential webs extending between them, at least one pocket for receiving a rolling element, in each of which a rolling element is guided axially by abutment of its end faces against the inner sides of the circumferential webs.

DE 10 2006 022 951 A1 is directed to the provision of a reliable, cost-effective rolling bearing cage with which on the one hand mechanical stresses of the cage and on the other hand an increased wear due to constraining forces can be avoided. DE 102006 022 951 A1 does not address the problem of the supply of lubricant to the rolling elements in general and to the tribological conditions when the rolling element end faces slide on the so-called ribs of the bearing inner ring or bearing outer ring delimiting the axial displacement of the rolling bodies.

In the known roller bearing cage, the inner sides of the circumferential webs are substantially flat and possibly - due to the dimensioning just large slewing bearings - provided with a minimum curvature in the circumferential direction. Conventional rolling elements, in particular tapered rollers, have an almost plane, if at all very slight, dimensioning effect. Fügig spherically shaped Wälzkörperstirnfläche on. Since the cage segments are usually performed relatively tightly over the Wälzkörperlängen be touched by the peripheral webs especially the end face areas of the rolling elements, which also serve as the mentioned sliding and supporting surfaces to the ribs on the inner and outer rolling bearing rings. At these it can lead to stripping of the lubricant or lubricant just in these for the friction conditions and material stress particularly critical cooperating surfaces - namely the Wälzkörperstirnflächen on the one hand and the inner surfaces facing the edges of the bearing rings on the other. This can occur in unfavorable operating situations, a lack of lubricant in the area of these cooperating sliding surfaces. At worst, this can lead to metallic contact between the rolling elements and the edges of the bearing rings, which in turn has increased friction and thus increased wear. Medium- and long-term consequence is an increased bearing friction and concomitant increased storage temperatures, which in turn further degrade the lubrication conditions. This self-reinforcing effect can eventually lead to significant wear on the cooperating sliding surfaces (functional surfaces) between rolling elements and said on-board abutment surfaces as well as disturbances of the kinematic conditions in the bearing, forced forces and ultimately premature bearing failure.

Against this background, the object of the invention to provide a roller bearing cage, which eliminates the above problems and in particular ensures a reliable undisturbed lubricant supply in the critical areas of the rolling bearing end faces.

This object is achieved by a rolling bearing cage with the features of claim 1. Accordingly, a generic rolling bearing cage is characterized in that the inside in each case to the connecting webs has a return. Advantageous embodiments of the invention are set forth in the following description and the dependent claims, the features of which can be used individually and in any combination with each other.

According to the invention, the inner side-that is to say the side of the circumferential ridge facing the rolling body end face-has a return in its region leading to the connecting webs. In other words, towards the transverse webs, the inside of at least one of the circumferential ridges within the respective rolling-body-receiving pocket is radially outward of the central region of the portion of the circumferential ridge located between the connecting webs. offset from the Wälzkörperstirnflächen away, so jumps back relative to the central region of the Umfangsteginnenseite. As a result, it is achieved that the guidance of the cage segments over this central region - i. so over the central portion of the circumferential ridge between two connecting webs - and the central portion of the Wälzkörperstirnflächen, e.g. a circular ring surface, takes place. By this constructive design, by which the inner side surfaces of the peripheral webs are withdrawn in the border region to the connecting webs, the edge region of the Wälzkörperstirnflächen not touched by the peripheral webs and thus the lubricant can not be affected. This eliminates the risk that lubricant is undesirably stripped on the peripheral webs and therefore is no longer available for the sliding lubrication between the Wälzkörperstirnflächen and the insides of the storage shelves (in-board surfaces). The lubrication conditions between Wälzkörperstirnflächen and the inner surfaces of the board so completely unaffected by the bearing cage.

For the realization of the recesses various advantageous developments of the invention are conceivable and expedient. Particularly preferably, the recesses can be formed by inward material reductions of the circumferential ridge or by material recesses on the peripheral ridge in each case toward the outgoing connecting webs. An alternative preferred development of the invention provides that the recesses are formed by an inner material thickening in the central web of the Wälzkörperstirnseite facing portion of the circumferential web.

With regard to the mechanical loads and the mechanical stresses induced in the bearing cage, a development of the invention is advantageous according to which the transitions to the recesses are rounded. This avoids mechanical stress-increasing peaks.

In this regard, a particularly preferred measure for reducing these mechanical voltage peaks is according to the invention in that at least one undercut is provided in the connection area between the circumferential web and the respective outgoing connecting web.

The invention further relates to a rolling bearing, comprising a roller bearing cage according to the invention.

Further advantages and aspects will become apparent from the drawing and the following description of the embodiments illustrated therein. Showing:

FIG. 1 shows a detail (segment) of a rolling bearing cage according to the invention,

2 shows schematically the guiding situation of a rolling element and

Figure 3 shows a detail of a roller bearing cage with a rolling element. The segment 1 of a rolling bearing cage shown in FIG. 1 is part of a roller bearing with a pitch circle diameter of more than 500 mm, which is suitable for particularly demanding operating conditions and in particular for operating temperatures up to 150 ° C. and which have one or more rolling element rows can. Such bearings can be particularly preferably used as a rotor main bearing in a wind turbine. Although the description of the figures is given on the basis of such a slewing bearing, the invention is by no means limited thereto or even to rolling bearing cages which are composed of several segments.

As seen in the circumferential direction U, the segment 1 shown of the roller bearing cage according to the invention comprises two peripheral circumferential webs 2, 3, which are sometimes also referred to as longitudinal webs. With regard to the respective radius of the peripheral ridge 2 is also referred to as outer peripheral ridge and the circumferential ridge 3 as an inner circumferential ridge. Each circumferential ridge has an inner side 5, 6 (not shown explicitly in FIG. 1, but only indicated by dashed lines as an example) rolling elements 4. The circumferential webs are interconnected by transverse connecting webs 10 to 14 and thereby at the same time in a plurality of circumferentially adjoining web sections -. 16, 17, 18, 19 - divided. The peripheral webs 2, 3, with their respective sections (e.g., 16, 18) and the connecting webs 10, 11 connecting them, form pockets 20, 21, 22, 23 for respectively receiving a rolling element. The rolling elements are guided by abutment of their respective radially outwardly or inwardly oriented end face 25, 26.

The inner sides 5, 6 each have in the connecting or transition areas to the connecting webs 10, 11; 12, 13, 14 recesses 30, 31, 32, 33 on. The meaning and function of the recesses, which are preferably symmetrical and equally formed in each pocket, are described below by way of example with reference to the pocket 21 and with reference to her Cooperation with the rolling elements 4 explained. The recesses 30, 31, 32, 33 are realized in the embodiment by internal material reductions 35, 36, 37, 38. As a result, recesses 40, 41, 42, 43 are formed relative to the remaining inner side 5, 6. Between these inner side portions 45, 46 of the circumferential webs 2, 3 are provided, which have a smaller spacing from one another. In other words: Between the respective recesses is a survey, which may be formed in the embodiment by appropriate material reductions, material removal or Materialausnehmungen. In the same way, however, the return jumps 40, 41, 42, 43 can also be formed by material thickenings on the inside in the region 45, 46 of the circumferential web 2 or 3 facing the central region 50, 51 of the rolling element end face.

As Figure 1 further shows, the transitions to the recesses 40 to 43 are characterized by comparatively large radii, e.g. 56, 57 formed, so that there is a very gentle and thus mechanical tips degrading transition geometry. Further preferably, in the respective connection region between the respective peripheral ridge 2, 3 and the respective outgoing connecting web 11, 12 is in each case an undercut, e.g. 65, 66 are provided.

Figure 2 illustrates the effect of this geometric configuration, already in Figure 1 by the thus realized, significantly extended distances between the facing surfaces - namely the respective end faces 25, 26 of the rolling elements 4 on the one hand and the facing inner surfaces 5, 6 of the circumferential webs 2, 3 on the other hand - is effected.

As Figure 2 schematically shows in addition thereto, in the (very schematically illustrated) pocket 21 of the rolling elements 4 is arranged in the form of a tapered roller, wherein the peripheral regions, ie the outer edge regions of the Wälzkörperstirnflächen not with the material of the cage - ie with the peripheral webs 2, 3 - come into contact. Rather, a mechanical contact only between the central regions 50, 51 of the rolling element. 4 and the central portions 45, 46 of the web portions 17, 19 are provided. This leaves at the peripheral areas 70, 71 of the Wälzkörperstirnseiten sufficient lubricant 76, 77, 78, 79 as schematically indicated in the contact area 80, 81 with the inner side 86, 87 of the respectively facing outer Lagerbords 90 and inner Lagerbords 91 acts.

This is ensured by simple means that the inner side surfaces of the circumferential webs are withdrawn in the region towards the connecting webs and that thereby the leadership of the cage segments only over the central region of the circumferential webs between the connecting webs and to the central region of the Wälzkörperstirnflächen out. The inner surfaces of the respective circumferential webs in the middle region of each pocket are thus increased and the areas are taken back to the larger diameters of the end faces of the rolling elements. As a result, the edge regions of the rolling element end faces are not touched by the cage material and, as a result, the necessary lubricant can not be undesirably stripped there as well. Thus, the lubricity between the rolling elements and the facing Lagerbordinnenseiten is optimized and unaffected by the rolling bearing cage.

FIG. 3 schematically shows a detail of a plan view of a cage according to the invention and a rolling element 4 located in a pocket. It can be seen that the rolling element 4 used with the cage according to the invention has a central recess 100 which is located at both end faces of the cage Rolling element 4 is formed. This depression

100 serves to center the rolling body during the processing of its lateral surface, so e.g. when grinding. The recess 100 is adjoined radially on the outside by a flat surface 101 of the end face. This plane surface

101 forms an annular surface and serves as a contact surface with the inner sides, seen here inside 5, the cage. To the plane surface

101 connects radially outwardly a curved surface 102 of the rolling element 4. The recess 100 is useful especially for large rolling elements for easier processing. Of course, the rolling elements can be formed without corresponding recesses 100 at its end faces. In this case, a circular, planar surface forms as a contact surface to the inside of the cage instead of the annular, flat surface 101 on each end face.

LIST OF REFERENCE NUMBERS

1 segment

2.3 peripheral ridge

4 rolling elements

5,6 inside

10, 11, 12, 13, 14 connecting webs

16, 17, 18, 19 web sections

20, 21, 22, 23 pockets

25.26 faces

30, 31, 32, 33 recesses

35, 36, 37, 38 Material reductions

40, 41, 42, 43 returns

45.46 areas

50.51 central area

56.57 radius

65.66 Hinterstich

70.71 peripheral area

76, 77, 78 79 Lubricant

80.81 contact area

90 outer bearing board

91 inner bearing board

100 wells

101 plane surface

102 curved surface

U circumferential direction

Claims

claims

1. Rolling bearing cage with two in the circumferential direction (U) extending peripheral webs (2, 3), each having a rolling elements (4) facing inside (5, 6), and with connecting webs (11, 12) between the peripheral webs (2 , 3) and with these pockets (21) for receiving the rolling elements (4), - wherein the rolling bearing cage by frontal contact of the rolling elements (4) on the inside (5, 6) at least one circumferential web (2, 3) axially guided, characterized in that the inner side (5, 6) in each case to the connecting webs (11, 12) towards a recess (40, 41, 42, 43).

2. rolling bearing cage according to claim 1, characterized in that the recesses (40, 41, 42, 43) by inside Materialvermin- tions (35, 36, 37, 38) of the peripheral ridge (2, 3) to the connecting webs (11, 12 ) are formed.

3. Rolling bearing cage according to claim 1, characterized in that the recesses (40, 41, 42, 43) by an inside Materialaufdickung in the central region (50, 51) of the Wälzkörperstirn- side (25, 26) facing portion (45, 46) of the circumferential ridge (2,

3) are formed.

4. rolling bearing cage according to at least one of claims 1, 2 or 3, characterized in that the transitions to the recesses (40, 41, 42, 43) are rounded.

5. rolling bearing cage according to at least one of the preceding claims, characterized in that in the connection region between the circumferential web (2, 3) and the respective outgoing connecting web (11, 12) an undercut (65, 66) is provided.

6. Rolling bearing, comprising a roller bearing cage according to at least one of the preceding claims.