WO2011018489A1

WO2011018489A1 - Cage segment for a plastics cage of a rolling contact bearing and rolling contact bearing with a cage segment of this type

Info

Publication number: WO2011018489A1
Application number: PCT/EP2010/061726
Authority: WO
Inventors: Rudolf Zeidlhack
Original assignee: Schaeffler Technologies Gmbh & Co. Kg
Priority date: 2009-08-13
Filing date: 2010-08-12
Publication date: 2011-02-17
Also published as: DE102009037422A1

Abstract

The invention relates to a cage segment of a plastics cage for a rolling contact bearing, in particular for a large rolling contact bearing designed as a radial deep groove ball bearing. The cage segment comprises two outer webs (17) and at least two connecting webs (18) connecting the outer webs (17) to each other, wherein a pocket (19) for receiving a rolling body (04) is formed in each case between the outer webs (17) and two connecting webs (18). According to the invention, the cage segment is divided in the axial direction. An axial coupling element (12, 13) is provided at a connecting point (09). The invention also relates to a rolling contact bearing with a cage according to the invention.

Description

Name of the invention

Cage segment for a plastic cage of a rolling bearing and

Rolling bearing with such a cage segment

description

FIELD OF THE INVENTION The invention relates to a cage segment for a plastic cage according to the preamble of claim 1. Generic cage segments comprise two concentric circumferential webs and connecting webs arranged therebetween. In each case between two connecting webs and the peripheral webs a pocket for receiving a rolling element is formed. The inventions fertil particularly relates to a retainer segment of a radial grooved ball bearing, which is to be operable at operating temperatures up to 150 ⁰ C and has a pitch circle diameter greater than 500 mm.

Such plastic cage segments are known from the prior art for some time and appreciated especially because of their low weight and cost-effective production. There are various solutions to allow swelling or thermal expansion of the cage material and thereby to prevent strong stresses in the cage and bearing, which are caused by the more thermally expanding plastic material of the cage than the usually made of steel remaining components of the bearing. DE 102 46 825 A1 describes a plastic cage, which consists of several segments. The cage described is particularly suitable for use in very large bearings with relatively small rolling elements. The cage segments lie loosely against one another at their outwardly directed concave end faces. The dimensioning of the segments is to be selected so that in a gap-free juxtaposition of the segments between the adjacent end faces of the first and the last segment, a gap remains to accommodate a swelling and / or temperature-induced expansion of the segments. However, the potential gap between see the cage segments has the disadvantage that during operation in and between the cage segments higher forces occur, which can lead to a plastic deformation or cracking of the cage segments. Increased bearing friction, noise, temperatures and thus a shortened bearing life are the result.

German Patent Disclosures DE 10 2006 022 951 A1 and DE 10 2007 048 655 A1 disclose plastic cage segments for large rolling bearings, which carry coupling elements on the end faces in order to achieve a play-related connection of the segments to the cage. Due to the even distribution of the play between the cage segments, mechanical stresses can be avoided. The described cage segments are designed for tapered roller bearings.

The object of the invention is to provide a cage segment for a plastic cage, in particular for a radial deep groove ball bearing (single or multi-row), whereby particular value is attached to a simple assembly in a self-retaining rolling bearing value. Furthermore, an improved guidance of the cage in the rolling bearing is to be achieved. A further object is to provide a radial deep groove ball bearing with a plastic cage formed from segments. The object is achieved by a cage segment having the features of claim 1 and by a rolling bearing having the features of claim 13.

A cage segment according to the invention initially comprises in a known manner two outer webs, which are interconnected by connecting webs. For radial deep groove ball bearings, the outer webs are offset axially. Several segments can be connected to form a cage. For this purpose, the segments on their end faces coupling elements, which are each connected to the coupling element of the next segment. Preferably, a first coupling element is provided on a first end side and a second coupling element is provided on a second end side, each of which is shaped complementary to one another and can be connected to one another in a form-fitting manner. This makes a simple connection to a cage (ring) possible. Between the outer webs and two connecting webs cage pockets are formed for receiving a rolling element. The connections at the coupling points are provided with a clearance fit. As a result, a swelling or temperature expansion of the cage formed by a plurality of segments can be accommodated in the coupling elements without mechanical stresses occurring. The clearance has a size that corresponds to a swelling or thermal expansion of the cage material in a predetermined tolerance range. Depending on the cage segment, one or more pockets may be formed. According to the invention, the cage segment has an axial pitch with a connection point. The connection point can be provided either between one of the outer webs and the connecting webs of the other outer web or in each case in the connecting webs and should preferably not be able to be separated without destruction. The connection point is executed in a preferred embodiment as a snap or snap connection and geometrically designed so that the joining takes place under a certain compressive force and an independent decoupling not can be done. If the connection point is provided in the middle of the track in the connecting webs, it must be formed in the circumferential direction so that no contact with the rolling elements takes place. If necessary, the joint is geometrically set back from the raceway.

The advantages of the invention are to be seen in particular in that the assembly of the rolling bearing with a plastic cage is easily possible. For this purpose, the rolling elements are first inserted between the two bearing rings. Subsequently, the cage segments divided in the axial direction, which were preferably assembled beforehand in the direction of rotation to form a "half" cage, are introduced from both bearing side surfaces between the rolling elements and connected to one another. The connection point in the circumferential direction is preferably structurally designed so that the connection can be released when a limit force is exceeded and when the speed falls below it, it can also be reconnected or latched together. Preferably, the connection point is designed as a snap connection, rivet or screw connection. The guide of the cage formed from the segments takes place via the flange surfaces of the bearing and / or via the rolling elements. In this case, the contact of the rolling elements in the cage pocket is to be loosened geometrically such that the rolling element (for example the ball) touches the cage pocket to the right and left of its largest diameter. Half the ball diameter should run freely in the middle. As a result, there is no stripping of the lubricant.

The segment is preferably held and guided in its position by means of guide knobs or webs both outwardly and inwardly toward the board diameters.

In a preferred embodiment, the guide webs are formed in skid shape to the friction and the sliding on the board surfaces improve.

An inventive rolling bearing, in particular a radial deep groove ball bearing comprises an inner ring, an outer ring and between them arranged in a cage rolling elements, wherein the cage is composed of the previously described segments. Advantageously, the flange surfaces on the outer ring can be ground to improve the sliding properties. The person skilled in the art knows the variants of the geometric design of such cages, therefore details of these are not discussed in greater detail.

The outer webs are tuned in height so that there is still a sufficiently large free space through which a lubricant can be fed into the camp interior.

At the connecting webs, the wall thicknesses are designed so that the rolling elements, especially the ball touches the cage only in a small diameter range and the segment is touched and guided only in this area of the balls. This largely prevents the wiping of the lubricant.

The invention will be explained in more detail with reference to FIGS. 1 shows a schematic representation of a rolling element-guided plastic cage according to the invention made of segments;

2 shows a schematic representation of a board-guided plastic cage according to the invention, formed from segments;

Fig. 3: five schematic representations of an axial connection point of a cage segment; Fig. 4: four variants of radial coupling elements in spatial representations. Fig. 1 shows a schematic representation of a detailed view of a radial deep groove ball bearing with a rolling body guided plastic cage. The bearing comprises in known manner an outer ring 01 and an inner ring 02, which are arranged concentrically to a bearing bore 03. Several balls 04 are arranged and held as rolling elements between the outer ring 01 and inner ring 02 in a raceway 06. The camp is self-holding. The balls 04 are held by a plastic cage, which is composed of several cage segments 07, at a distance.

The cage segment 07 comprises radial coupling elements 08, with which a plurality of cage segments can be connected to form a cage. The radial coupling elements 08 are designed in principle known type and will be explained in more detail below. The cage segment 07 is according to the invention divided in the axial direction and connectable at a junction 09. The leadership of the cage is done by the balls 04 via guide elements, not shown.

When mounting the bearing, the balls 04 are first inserted between the inner ring 02 and outer ring 01. Thereafter, the cage segments 07 divided in the axial direction are introduced from both bearing side surfaces between the rolling bodies. Preferably, the split cage segments are first assembled into partial rings and then the axial connection between the partial rings produced. Fig. 2 also shows a schematic representation of a radial deep groove ball bearing with a board-guided plastic cage. The bearing basically has the same known structure, therefore, carry the same components the same reference numerals as in Fig. 1.

The guide of the cage takes place on board surfaces 10 of the inner ring 02 and the outer ring 01. As guide elements here, in contrast to the embodiment shown in Fig. 1 guide webs 11 are formed for guiding the cage on the flange surfaces 10. Preferably, the guide webs 11 are formed skid-shaped to minimize frictional forces.

In Fig. 3, several exemplary possibilities of the axial connection point 09 are shown. In this case, Fig. A) to d) snap connections and Fig. E) shows a screw or rivet connection, in each case in a sectional view and a plan view. Of course, combinations of snap and screw or rivet can be selected.

The snap connections are each carried out with complementarily shaped axial coupling elements 12, 13 which have the following different cross-sectional shapes: Fig. A) rectangular, Fig. B) spherical, Fig. C) semicircular, Fig. D) disc-shaped (rectangular cross-section).

In Fig. E) a connection by means of connecting means 14 (rivets, pins, screws or the like) is shown, which must be secured against self-loosening by known means. In addition, a positive mounting aid 16 may be provided.

FIG. 4 shows various possibilities of radial coupling elements. The figures each show a cage segment with outer webs 17, which are interconnected by connecting webs 18. Between the connecting webs 18 pockets 19 are formed for receiving a respective rolling element. On one of the end faces 21 of the cage segment 17 coupling webs 22 are provided in extension of the outer webs. At the opposite end face, the outer webs 17 coupling recesses 23, in wel surface can engage the corresponding coupling webs 22 of a further identically constructed cage segment. In the region of the coupling webs 22, latching projections 24 are provided which engage in latching recesses 26 of the coupling recess 23 during assembly. The breakdown into such segments facilitates the production especially for large bearing diameters.

The various design options are shown in the other figures. Fig. B) shows that the coupling webs 22 have the latching recesses 26, in which latching projections 24 of the next cage segment can engage. In this embodiment, the latching projections 24 protrude in the longitudinal direction of the cage segment in each case to the outside. In the detailed illustration of Fig. B) it can be seen that the locking projection 24 within the recess 26 has a game s in the circumferential direction of the cage segment to accommodate expansions can.

Fig. C) shows an asymmetrical design of the radial coupling elements. On each of the end faces 21, a coupling web 22 and a coupling recess 23 are provided in each case. The coupling webs 22 carry the latching projections 24, while the recesses 26 are provided on the coupling recesses 23.

In Fig. D) a dovetail-like radial coupling point is shown, in which on the coupling webs 22 dovetail-shaped Rastausnehmun- gene 26 are formed, while at the coupling recesses 23 complementary shaped locking projections 24 are provided.

Guiding elements for ball guides are not explained in detail here, since those skilled in the art are familiar. LIST OF REFERENCE NUMBERS

01 outer ring

02 lnn

03 bearing bore

04 ball

05 -

06 career

07 cage segment

08 Radial coupling elements

09 connection point

10 board area

11 guide bar

12 axial coupling element

13 axial coupling element

14 connecting means

15 -

16 assembly aid

17 outer pier

18 connecting bridge

19 bag

20 -

21 front side

22 coupling bridge

23 coupling recess

24 latching projection

25 -

26 recess

Claims

claims

1. Cage segment of a plastic cage for a rolling bearing, in particular for a slewing bearing, with at least two outer webs (17) and at least two outer webs (17) interconnecting connecting webs (18), wherein in each case between the outer webs (17) and two connecting webs (18) a bag (19) for receiving a

Rolling element (04) is formed, characterized in that the cage segment is divided in the axial direction prior to assembly and during assembly at a connection point (09) via an axial coupling element (12, 13) is connected.

2. cage segment according to claim 1, characterized in that the axial coupling element (12, 13) respectively between each of the connecting webs (18) and one of the outer webs (17) is provided.

3. cage segment according to claim 1, characterized in that the axial coupling element (12, 13) respectively at the connecting webs (18) is provided.

4. Cage segment according to one of claims 1 to 3, characterized in that each of the connecting webs an axial coupling element

(12, 13).

5. Cage segment according to one of claims 1 to 4, characterized in that the axial coupling element (12, 13) is a snap connection and / or a rivet connection or a screw connection.

6. cage segment according to claim 5, characterized in that the snap connection by two complementarily shaped coupling elements (12, 13) is formed.

7. Cage segment according to claim 6, characterized in that the coupling elements (12, 13) are formed in their cross-section rectangular, spherical, half-round or oval.

8. Cage segment according to one of claims 1 to 7, characterized in that it comprises at its end faces (21) Radial coupling elements (22, 23, 24, 26) for chaining together several cage segments to a cage.

9. Cage segment according to one of claims 1 to 8, characterized in that it comprises guide elements for guiding the cage in the rolling bearing.

10. Cage segment according to claim 9, characterized in that the guide elements correspond with the rolling elements.

11. cage segment according to claim 9 or 10, characterized in that the guide elements with flange surfaces (09) of the rolling bearing correspond, the one or both sides of the running surfaces on the inner ring (02) and / or on the outer ring (01) are formed ,

12. Cage segment according to claim 11, characterized in that the guide elements as skid-shaped guide webs (11) facing the outer or inner ring (01, 02) are formed.

13. Rolling, in particular radial deep groove ball bearings with an inner ring (02), an outer ring (01) and arranged therebetween in a cage rolling elements (04), characterized in that the cage is composed of cage segments according to one of claims 1 to 11.

14. Rolling bearing according to claim 13, characterized in that the outer ring (01) has ground flange surfaces.