WO2008116707A1

WO2008116707A1 - Radial roller bearing

Info

Publication number: WO2008116707A1
Application number: PCT/EP2008/052015
Authority: WO
Inventors: Christian Hoffinger; Michael Bogner
Original assignee: Schaeffler Kg
Priority date: 2007-03-23
Filing date: 2008-02-19
Publication date: 2008-10-02
Also published as: DE102007013942A1

Abstract

The invention relates to a radial roller bearing comprising at least one outer bearing ring (1) having an outer track and one inner track in addition to a plurality of roller bodies (4) that are arranged therebetween, said roller bodies rolling along the tracks with the running surfaces thereof. In order to avoid slip, the clamping elements interact with journals that are connected to the roller bodies (4) in an axial manner outside the front surfaces of the roller bodies. The invention is characterised in that the clamping elements (8, 15) work on both sides of each individual journal (7, 9) of the roller body (4) in the same direction that is radially inward or radially outward, work in the direction of the periphery but alternating from radially inward and radially outward.

Description

Name of the invention

Radial rolling bearings

Field of application of the invention

The invention relates to a radial rolling bearing, which consists of at least one outer bearing ring with an outer raceway and an inner raceway and a plurality of rolling elements arranged therebetween, which roll with their running surfaces on the raceways, wherein to avoid slip on axially outside the Wälzkörperstirnflächen with the rolling elements connected pin clamping elements act.

Background of the invention

The person skilled in rolling bearing technology, it is well known that radial roller bearings have sufficient load an optimal kinematic operating condition in which the rolling elements roll without sliding on the raceways of the bearing rings. Furthermore, it is known from low-loaded, heavy radial rolling bearings, that the rolling element of the rolling elements and the bearing cage due to the friction in the bearing or due to the high mass forces of the Wälzkörperkranzes and the low contact force between the rolling elements and the raceways not turns more with the kinematic speed. The speed of the Wälzkörperkran- zes thus remains compared to the kinematic speed back, so that the rolling elements are in a kinematic not optimal state through which there is slip between these rolling elements and at least one career. In this case, at the contact surfaces between the rolling elements and the raceway, a lubricating film build up, which is destroyed by a sudden change in speed or load, so that at the slip-contact point within a short time no sufficient lubricating film is present. This has the consequence that it comes to a metallic contact of the raceway with the rolling elements and these slide on the track until the Rolling elements are accelerated to the kinematic speed. This large differential speed between the raceway and the rolling elements, as well as the absence of a separating lubricating film is thus responsible for the fact that it comes in the surfaces of the raceway and rolling elements to high tangential stresses, with severe signs of wear, such as roughening of the track, material tearing and smearing usually associated with micro-fittings and can lead to premature failure of the radial roller bearing.

In order to avoid this slip effect and the disadvantages resulting therefrom, radial bearings have already become known, which use elastic rolling elements at at least one circumferential point.

Thus, for example, in DE 511 985 A a radial roller bearing is described that uses resilient rolling elements in the form of a helical spring, so that the bearing is preloaded in the radial direction. The disadvantage here is that such spring-like rolling elements can be produced only in a very complex manner and also there is a risk of Tribokorrosion within the spring.

Another type of elastic rolling elements is previously known from JP 032 778 09 A1. This bearing is characterized in that at least one circumferential point a rolling body is arranged made of a plastic. In addition to the different use of rolling elements made of plastic and steel might be a disadvantage that the carrying capacity of such a bearing is considerably limited by the plastic rolling elements used.

From US 3,930,693 a radial roller bearing has become known, the rolling elements are designed as elastic hollow rollers. However, it is disadvantageous that the capacity of such a bearing is also limited by such hollow rollers. In practice, it has also been found that such hollow rollers are often unable to cope with the alternating bending stresses that occur and therefore also have to be designed in several parts. From DE 32 16 010 A1 a generic radial roller bearing is previously known, whose cylindrical rolling elements have at their end faces pins which are surrounded by a clamping element. According to an exemplary embodiment of this prior art, the design can be made such that the tensioning element is formed by elastic or spring-biased bands, one of which acts on the pins at one and at the other end of the rolling elements. By this measure, each rolling element is pressed in the load-free zone on the one hand to the inner and on the other side of the outer race, thereby preventing sliding friction.

In this bearing arrangement is disadvantageous in that each rolling element is pressed simultaneously to the outer and to the inner raceway, so that they must assume a tilted position. This tilting in turn requires that no linear contact of the rolling elements on the raceways, but only a punk-shaped is realized. It may therefore be doubted whether an effective slip reduction can be achieved with this point-only system. It is also disadvantageous that the tensioning element is a band that has to be prestressed via a complicated and thus complex spring mechanism.

Summary of the invention

Based on the stated disadvantages of the known prior art, the invention is therefore based on the object to provide a generic radial rolling bearing, which reliably prevents the sliding friction between the rolling elements on the one hand and the raceways on the other hand.

According to the invention this object is achieved by the characterizing part of claim 1 in conjunction with the preamble thereof in that the clamping elements on both sides of each pin of a rolling element act in the same direction radially outward or radially inward, but in the circumferential direction but alternately act radially outward and radially inward.

The advantage of the solution according to the invention consists essentially in the fact that without affecting the load rating, the rolling elements are continuously driven via a frictional connection between these and the raceways and thus show no slip outside the load zone. Characterized in that a rolling element is pressed with its entire length extension to the outer raceway and the next rolling element with its entire length extension to the inner raceway, in contrast to the previous generic prior art, a linear contact of lateral surface of the rolling elements and the respective raceways realized, so that under all conditions slip-free, which leads to a significant increase in the service life of the bearing assembly.

In a further embodiment of the invention, it is possible that the clamping element is a belt which is supported on both sides of the pin and acting on the pins of successive rolling elements alternately inside and outside of the pitch circle. Such endless belts are available as inexpensive purchased parts in various sizes on the market. In this context, it has proven to be advantageous if the pins are enclosed by a steel bushing, with the help of which the desired preload within the bearing can be acted upon.

A preferred embodiment of the invention provides that the rolling elements have integrally formed pins on their end faces, wherein roller bearings are arranged according to an additional further feature between the pin on the one hand and the clamping element on the other hand to reduce the friction.

According to a further variant of the invention, it is provided that each rolling element is provided with a central bore into which a bolt projecting beyond the rolling body end faces is inserted. Also in this case it has become Reduction of the friction proved to be advantageous if, on the other hand rolling bearings are arranged between the bolt on the one hand and the central bore of each rolling element.

According to a further variant of the invention, the clamping element should be a disk-shaped ring, which is connected on both sides with the pins, wherein the guide plates connected to the pins have receiving bores for the pins. In this context, it is provided according to a further additional feature that adjacent guide plates are elastically connected to each other by a radially outer web and a radially inner web are circumferentially offset from each other, the webs meander with each other and with the guide plates via radially extending side parts are connected.

Also in this case, the guided through the disc-shaped ring individual rolling elements are alternately pressed against the outer raceway or to the inner race, so that even outside the load zone, despite the presence of a possible bearing clearance for constant contact between the rolling elements and the raceways is taken care of. Due to the resulting bias voltage slippage of the rolling elements is reliably avoided even in a non-loaded zone.

Further features of the invention will become apparent from the following description and from the drawings, in which two embodiments of the invention are shown in simplified form.

Brief description of the drawings

Show it:

1 shows a longitudinal section through a radial rolling bearing with a first variant according to the invention, FIG. 2 shows a side view of FIG. 1,

Figure 3 is a perspective view of the bearing according to

FIG. 1,

FIG. 4 shows a longitudinal section through a radial rolling bearing with a second variant according to the invention,

FIG. 5 is a side view of FIG. 4,

Figure 5a shows an enlarged view of a section

FIG. 5,

FIG. 5b a representation of two rolling elements in the load range,

Figure 5c is a representation of two rolling elements in the unloaded area and

Figures 6 and 7 is an enlarged view of a single cylindrical rolling element.

Detailed description of the drawings

The radial roller bearing according to FIGS. 1, 2 and 3 consists of the bearing outer ring 1, which is provided on both sides with radially inwardly directed ribs 2, 3 and provides the outer raceway for the cylindrical rolling bodies 4. The associated inner race is provided by the bordlosen bearing inner ring 5, wherein the two bearing rings 1, 5 are arranged concentrically with each other to the bearing axis 6. Each individual rolling element 4 is provided on its front side with a respective pin 7, which are formed by a bolt 22 which penetrates the rolling element 4 completely beyond the end faces. As can be seen in particular from FIGS. 2 and 3, the belt 8 engages on both sides on the journal 7 radially inside the pitch circle T and presses the rolling body 4 against the bearing outer ring 1, while the belt 8 engages the next rolling element 4 on the pin 7 outside the pitch circle T and the rolling element 4 presses against the bearing inner ring 5. In this way, it is ensured that a rolling element 4 is pressed against the outer raceway and the next rolling elements 4 in the circumferential direction against the inner raceway. This ensures that all rolling elements 4 are pressed outside the load zone against one of the two raceways, so that slippage is prevented even in this area.

As seen from the enlarged view of a single rolling element 4 according to Figure 7, this is provided with a continuous central bore 12 in which a bolt 22 is received over two spaced rolling bearings 11, the two ends of which form the pins 7. In the present embodiment, the rolling bearings 11 are formed as a combined cylindrical roller and ball bearings. At both ends of the pin 22 and the pin 7 is connected to a respective steel bushing 10 whose diameter is different, so that with the help of this steel bushing 10 can be acted upon the tension of the belt 8.

In Figure 6, a single rolling element 4 is shown, the outer race is provided by the bearing outer ring 1 and the inner raceway is formed by a shaft 13. As can be seen, according to this embodiment, the rolling element 4 is provided at its two end faces with integrally formed pins 9, which in turn are surrounded on both sides by a rolling bearing 14.

The second variant of the invention shown in Figures 4, 5 and 5a differs from the first variant of the invention shown in Figures 1 to 3 only in that instead of a belt 8, a disc-shaped ring 15 is used as a clamping element. As can be seen in particular from the enlarged illustration 5a, this disk-shaped ring 15 consists of the guide plate 16, which is connected to the pin 7. The two adjacently arranged guide plates 16 are arranged in the radial direction spaced from each other and offset from each other webs 17, 18, which in turn hold on the side members 19 and 21 in contact with each other. This ensures that, on the one hand, such a disk-shaped ring 15 also has a certain elasticity in the circumferential direction and, on the other hand, that the cylindrical rolling elements 4 are pressed alternately against the outer raceway and against the inner raceway.

In Figures 5b and 5c, the rolling elements 4 are arranged with the associated pin 7 without clamping element between the two bearing rings 1 and 5 for reasons of simplicity. The load zone shown in FIG. 5 b shows that in this area the rolling elements 4 both have contact with the raceway of the bearing outer ring 1 and with the raceway of the bearing inner ring 5. The rolling elements 4 rotate on the raceways of the bearing rings without sliding, ie, the rolling bearing has an optimal kinematic operating condition without slippage. So that this kinematically optimal operating state is maintained even outside the load zone, which is shown in Figure 5c, the rolling elements 4 are alternately pressed by the clamping elements 8, 15, not shown, to the outer race or to the inner race, as the accompanying arrows illustrate. By this contact of the rolling elements 4 with a career slip is reliably avoided. While the left rolling element 4 is pressed by two-sided attack of the clamping elements on the pin 7 radially outward, the rolling element 4 arranged to the right thereof is pressed in reverse radially inward.

reference numeral

1 bearing outer ring

2 board

3 board

4 rolling elements

5 bearing inner ring

6 bearing axis

7 cones

8 straps

9 cones

10 steel bush

11 rolling bearings

12 centric bore

13 wave

14 rolling bearings

15 disc-shaped ring

16 guide strap

17 footbridge

18 footbridge

19 side panel

20 side panel

21 side panel

22 bolts

T pitch circle

Claims

claims

1. Radial rolling bearing, which consists of at least one outer bearing ring (1) with an outer raceway and an inner raceway and a plurality of interposed rolling elements (4), with their

Roll running surfaces on the raceways, wherein to avoid slippage on axially outside the Wälzkörperstirnflächen with the rolling elements (4) connected pin tension elements act, characterized in that the clamping elements (8, 15) on each side of each pin (7, 9) of a rolling element (4) act in the same direction radially outward or radially inward, but act in the circumferential direction alternately radially outward and radially inward.

2. Radial rolling bearing according to claim 1, characterized in that the clamping element is a belt (8), which is on both sides of the pin

(7, 9) supported and on the pins (7, 9) of successive rolling elements (4) acts alternately inside and outside the pitch circle T.

3. Radial rolling bearing according to claim 2, characterized in that for adjusting the bias of the belt (8) of the pin (7, 9) by a steel bushing (10) is enclosed.

4. Radial rolling bearing according to claim 1, characterized in that the rolling elements (4) integrally formed on their end faces pin (9).

5. Radial rolling bearing according to claim 4, characterized in that between the pins (9) on the one hand and the clamping element on the other rolling bearings (14) are arranged.

6. Radial rolling bearing according to claim 1, characterized in that each rolling element (4) with a central bore (12) is provided, in which a Wälzkörperstirnflächen superior bolt (22) is inserted.

7. Radial rolling bearing according to claim 6, characterized in that between the bolt (22) on the one hand and the central bore (12) of each rolling element (4) on the other hand roller bearings (11) are arranged.

8. Radial rolling bearing according to claim 1, characterized in that the clamping element is a disc-shaped ring (15) which is connected on both sides with the pins (7), wherein the pins (7) connected to the guide plates (16) receiving bores for the pins ( 7).

9. radial roller bearing according to claim 8, characterized in that adjacently arranged guide plates (16) are elastically connected to each other by a radially outer web (17) and a radially inner web (18) are arranged offset from one another in the circumferential direction, the webs ( 17, 18) are connected to one another in a meandering manner with one another and with the guide straps (16) via radially extending side parts (19, 20, 21).