DE102006044805A1 - Radial roller bearing, particularly for bearing partly small loaded shaft in heavy machines, has rolling elements, where individual rolling element is pressed independently on its extent position hydraulically over pressure oil pad - Google Patents

Abstract

The radial roller bearing has an outside bearing ring (2) with an outside track (5) and an internal bearing ring (6) with an internal track (7) as well as a multiple rolling element arranged between the bearing rings. An individual rolling element that each individual rolling member is pressed independently on its extent position hydraulically over a pressure oil pad in radial direction against the internal bearing ring or the outside bearing ring, so that slip is avoided by the permanent contact between the rolling element and the tracks.

Description

Field of application of the invention

The The invention relates to a radial roller bearing, which essentially from an outer bearing ring with an outer career and an inner race having an inner raceway and a plurality arranged between the bearing rings rolling elements, with their treads Roll on the raceways of the bearing rings and through a bearing cage in the circumferential direction evenly spaced are held, with the bearing cage as a disc cage is formed, which in a centrally disposed annular groove of the outer or inner Bearing ring freely rotatably guided is and at its inner or outer diameter several, evenly over the Scope distributed, the rolling elements receiving Having pockets.

Background of the invention

the Specialist in rolling bearing technology It is well known that radial rolling bearings with sufficient load have an optimal kinematic operating state, in which the rolling elements without to slide on the raceways of the bearing rings unroll. Furthermore It is known from low loaded, heavy radial rolling bearings that are from the rolling elements and their camp cage existing rolling element ring due to friction in the bearing or because of the high inertia force of the Wälzkörperkranzes and the low contact force between the rolling elements and the raceways not with the kinematic speed rotates. The speed of the Wälzkörperkranzes thus stays opposite the kinematic speed back, so that the rolling elements in a kinematic not optimal state by the between these rolling elements and at least one career slip is present. It can be at the contact surfaces between the rolling elements and build up a lubricating film on the raceway, but at a sudden or load change destroyed so that at the slip-contact point within the shortest possible time Time is no longer sufficient lubricating film. This has to Consequence, that it leads to a metallic contact of the raceway with the Rolling comes and these slide on the track until the rolling elements on the kinematic speed are accelerated. This size Differential speed between the raceway and the rolling elements as well The lack of a separating lubricating film is thus the reason that it in the surfaces the raceway and the rolling elements to high tangential tensions comes with strong signs of wear, such as roughening of the track, Materialaufreißungen and lashings zumeinst associated with micropittings and premature Failure of the radial rolling bearing to lead can.

to Avoidance of this slip effect and the resulting disadvantages Radial bearings are already known, which at least one peripheral point used elastically trained rolling elements.

For example, in the DE 511 985 A a radial rolling bearing described which uses resilient rolling elements in the form of a helical spring, so that the bearing is biased 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 from the JP 032 778 09 A1 previously known. 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 may be a disadvantage that the carrying capacity of such a bearing is under certain circumstances significantly limited by the plastic rolling elements used.

From the 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 such hollow rollers have a high Lagerreibmoment due to the energy expended to their deformation. In addition, the bearing capacity of such a bearing should also be limited by the 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.

To avoid this slip effect and the resulting disadvantages is DE 932 942 proposed a rolling bearing with increased rolling resistance, which consists essentially of an outer bearing ring with an inner raceway and an inner bearing ring with an outer raceway and a plurality between the bearing rings on the race rolling rolling elements, which are spaced by a bearing cage in the circumferential direction at regular intervals being held. In this rolling bearing, the outer bearing ring has a circumferential groove axially centrally in the raceway, in which an elastic, acting in the direction of the bearing longitudinal axis clamping element is arranged, which presses the rolling elements against the raceway of the other bearing ring. This clamping element is designed as a plastic ring, which fills the groove in the raceway of the outer bearing ring and slightly on the career ago projects so that it is deformed during rolling over of the rolling elements and as a result increases their rolling resistance.

adversely in such bearings However, it is that arranged in the raceway of the outer bearing ring Plastic ring has a low modulus of elasticity, by the the plastic ring depends of the respective plastic only over one small immutable Preload. About that In addition, under real operating conditions, it has been shown that Such a plastic ring is very sensitive to wear, since its material through the permanent rolling over through the rolling elements of a permanent Walk stress is subject to, by the already after a short time the elasticity and the preload force of the material wears off and barely over a longer period of operation is available. The relaxation of the elasticity and the prestressing force of a such plastic ring is still by the abrasion the rolling body forces as well reinforced by that the plastic ring has a higher Expansion coefficient than the bearing ring has and thus at the operating temperature of the bearing radially expands such that its Walk stress and wear is even higher. Furthermore are the applications limited by bearings with such plastic rings, as in many make for the Stock special lubricants used with chemical ingredients which react aggressively to the plastic parts.

The above-described possibilities for reducing slip are not particularly suitable for rolling bearings, in which the rolling elements are guided in a disc cage, which is slidably guided in an annular groove of the outer and inner ring. Such a rolling bearing in the form of a cylindrical roller bearing is from the DE 42 44 091 C2 previously known. As can be seen from the figures and the associated description, the rolling elements formed as cylindrical rollers are received in a disc cage, which is guided with its outer circumferential surface slidably in a circumferential annular groove of the bearing outer ring. Such cages are a combination of the previously known full complement bearings and the previously known cage bearings, which basically combine both advantages in itself. On the one hand, they have due to the large number of housed rolling elements on a high load rating and, secondly, due to the existing cage high rotational speeds are possible, please include. The disadvantage here is that even this optimized rolling bearing tends to slip.

Summary of the invention

outgoing from the disadvantages of the known prior art is the invention Therefore, the object of a radial rolling bearing, in particular for Storage of partially lightly loaded waves used in heavy machinery is designed to help prevent slippage between the rolling elements and whose one raceway does not use a mechanically acting tensioning element must become.

According to the invention this Task according to the characterizing part of claim 1 in conjunction solved with the preamble in that each individual rolling element regardless of its circumferential position hydraulically via a pressure oil pad in the radial direction against the inner bearing ring or the outer bearing ring is pressed, so by the constant contact between the Rolling elements and the raceways slip is avoided.

The drive of the rolling elements, and thus also the Wälzkörperkranzes, is frictionally by a permanent contact of each rolling element with one of the bearing rings. If the disc cage is guided in the outer bearing ring, each individual rolling element is pressed against the inner bearing ring by means of a radial force component which is hydraulically realized by the pressure oil cushion. In the opposite case, ie, when the disc cage is guided in a groove of the inner bearing ring, the rolling elements are pressed against the raceway of the outer bearing ring. In this way, regardless of the respective position of the rolling element in the bearing a continuous rolling contact between the rolling elements and the raceways is given. Depending on the position in the load zone or in the load-free zone, the disc cage will occupy an ever-changing distance between its peripheral surface and the centrally located annular groove in one of the bearing rings. Depending on its position, the disc cage wanders in the radial direction, so that the Ab changed between cage back and the bottom of the annular groove, resulting in a tumbling motion of the disc cage. In this context, it has proven to be advantageous if the disc cage and the annular groove for guiding the disc cage to minimize oil loss have a slight axial play. Another compensation of the bearing clearance between rolling elements and the pockets of the disc cage. The former migrates in the radial direction within the pocket depending on the position in the warehouse, ie, inside or outside the load zone. On the constantly applied pressure between the bearing rings and the rolling elements and the associated frictional engagement can be effectively prevented both the slip of the individual rolling elements (by braking the rolling element outside the load zone and strong acceleration at reentry) and the slippage of the whole rolling element , The energy required for the pressure oil supply can also be minimized if a be load-dependent pressure control is provided. Due to decreasing risk of slipping, it is expected that with high radial load of the bearing less additional contact pressure and thus less oil pressure is required.

When Another positive side effect for slip minimization is proven, that the bearing friction in comparison to a conventional disc cage again reduced because the contacts between the cage, rolling elements and raceways of the bearing rings are always well lubricated. There are quasi hydrostatic conditions.

Further advantageous embodiments of the Invention are in the subclaims described.

So is provided according to claim 2, that the rolling elements arranged as in the disc cage Cylindrical rollers are formed, at its in the outer bearing ring arranged annular groove facing peripheral surface is slidably guided. Such an arrangement can in a particularly advantageous manner in the Extraction of wind energy used as in this special Case often low radial loads of a stored shaft and the slip states associated therewith occur, which are described in the above Way can be effectively prevented.

To Claim 3, it has proved to be expedient that the peripheral surface of disk cage has a ring-like release in the area of the pockets is provided with radial through holes. In this way can that from the outer bearing ring supplied pressure oil be easily guided into the pockets of the disc cage.

Out another additional Feature according to claim 4, the pockets of the disc cage with a sickle-like Be provided with an exemption. These recessed in the radial direction Exemptions provide for a particularly favorable pressure oil build-up for pressing the rolling elements one of the bearing rings.

Out Claim 5 shows that the outer bearing ring in the area of his lateral surface is provided with a circumferential groove on at least one Circumferential point over a radial bore connected to the disk cage receiving annular groove is. Also, this embodiment of the invention care for rapid access of the pressurized lubricant in the warehouse interior.

Finally is provided according to a last feature of the invention according to claim 6, that the outer bearing ring is formed in two parts, with both ring halves at least one circumferential point with are each provided with a recess, in which a holding element used is. This two-piece bearing ring allows easy installation the overall bearing arrangement.

Brief description of the drawings

Further Features of the invention will become apparent from the following description and from the drawings, in which an embodiment of the invention is shown in simplified form.

It demonstrate:

1 an axial section through an inventively designed radial roller bearing in perspective view,

2 an enlarged view of a detail 1 .

3 a perspective view of a disc cage according to the invention and

4 an enlarged view of a disc cage after 3 ,

Detailed description of the drawings

To 1 has the trained as a cylindrical roller bearings radial bearing 1 the outer bearing ring 2 on, on both sides with radially inward Borden 3 . 4 which is the outer raceway 5 limit in the axial direction. The associated inner bearing ring 6 with the inner raceway 7 has left side the board 8th on, which is directed radially outwards and the board 4 opposite. Both bearing rings 2 . 6 are concentric with 9 designated bearing axis arranged. On the careers 7 and 5 roll rolling elements in the form of cylindrical rollers 10 passing through the disc cage 11 are kept at a distance from each other in the circumferential direction.

As in particular from the 2 . 3 and 4 can be seen, is the disc cage 11 with radially in the direction of the bearing axis 9 pointing webs 12 provided, the two-sided pockets 13 limit, in which the cylindrical rolling elements 10 are housed. The outer bearing ring 2 is formed in two parts and consists of the two ring halves 14 . 15 at the dividing plane 16 lie together. The cohesion of both ring halves 14 . 15 done by holding elements 17 in recesses 18 are used, which of the ring halves 14 . 15 are placed. How out 2 can be seen, is the disc cage 11 with its back sliding in the ring groove 19 guided, in turn, by the two ring halves 14 . 15 is formed. Above the dividing plane 16 is a V-shaped circumferential groove 20 is arranged at at least one circumferential location with the radial bore 28 is provided, which the V-shaped groove 20 and the disc cage 11 receiving annular groove 19 connects with each other. As the 3 and 4 further show is the disc cage 11 on its outer peripheral surface with the annular release 21 provided on both sides of the radially higher walls 22 . 23 is limited. On the inside there are sickle-like exemptions in the area of the pockets 24 arranged in the axial direction through the walls standing higher in the radial direction 25 . 26 are limited. At the apex of the bags 13 is the radial through hole 27 arranged, which is the outer ring-like exemption 21 and the inner sickle-like release 24 connects with each other.

Will now be the outer bearing ring 2 of in 1 shown radial roller bearing 1 firmly inserted into an unillustrated housing, while the inner bearing ring 6 a likewise not shown shaft which receives around the bearing axis 9 rotates, pressure oil is supplied via the housing, not shown, taking the following path:
It passes from the housing initially in the V-shaped groove 20 of the outer bearing ring 2 and reaches from there via the radial bore 28 the ring groove 19 in which the disc cage 11 is guided. From there, the pressurized lubricant reaches via the passage bore 27 the pocket 13 , being at the apex of the sickle-like release 24 empties. From there it is distributed in the circumferential direction within the sickle-like release 24 and ensures that the cylindrical rollers 10 by this built-up oil pressure in the direction of the inner raceway 7 of the inner bearing ring 6 be pressed so that regardless of the individual position egg ner each cylindrical roller 10 within the radial rolling bearing 1 both contact with the outer raceway 2 as well as contact with the inner raceway 7 is given and slippage is reduced or switched off in this way. In the load zone is the with 29 designated gap between the back of Scheibenkä figs 11 and the ring groove 19 be smaller than he is in the unloaded zone. The same applies to the reason for the cylindrical rollers 10 to. In the unloaded zone, the distance between the reason of the sickle-like release 24 and the lateral surface of the cylindrical roller 10 be larger than in the load zone.

The invention is not limited to the described embodiment in the form of a cylindrical roller bearing whose disc cage 11 in the outer bearing ring 2 is housed. It is equally possible that the rolling elements are not considered cylindrical rollers 10 are formed, but as balls, wherein the disc cage 11 in a groove of the inner bearing ring 6 is arranged.

The respective variant is decided by the special arrangement case. Is the outer bearing ring 2 rotatably disposed in a housing and the inner bearing ring 6 connected to a rotatable shaft, so the disc cage in the outer bearing ring 2 guided. This variant is particularly suitable for wind turbine gearboxes, since there waves often run at least temporarily with very little load and are therefore very susceptible to slipping. Is, however, the inner bearing ring 2 connected to a fixed axle, around which the outer bearing ring 2 rotates, is the disc cage 11 through the inner bearing ring 6 guided.

1

radial bearings

2

outer bearing ring

3

shelf

4

shelf

5

outer career

6

internal bearing ring

7

inner career

8th

shelf

9

bearing axle

10

cylindrical roller

11

disk cage

12

web

13

bag

14

ring half

15

ring half

16

parting plane

17

retaining element

18

recess

19

ring groove

20

groove

21

annular exemption

22

wall

23

wall

24

sickle-shaped exemption

25

wall

26

wall

27

Through bore

28

radial bore

29

gap

Claims (6)

Radial rolling bearing ( 1 ), which essentially consists of an outer bearing ring ( 2 ) with an outer raceway ( 5 ) and an inner bearing ring ( 6 ) with an inner raceway ( 7 ) and a plurality between the bearing rings ( 2 . 6 ) arranged rolling elements, which with their running surfaces on the raceways ( 5 . 7 ) of the bearing rings ( 2 . 6 ) and held by a bearing cage in the circumferential direction at regular intervals to each other, wherein the bearing cage as a disc cage ( 11 ) is formed in a centrally disposed annular groove ( 19 ) of the outer or inner bearing ring ( 2 . 6 ) freely rotatable is guided and at its inner or outer diameter a plurality of evenly distributed over the circumference, the rolling elements receiving pockets ( 13 ), characterized in that each individual rolling element independently of its circumferential position hydraulically via a pressure oil pad in the radial direction against the inner bearing ring ( 6 ) or the outer bearing ring ( 2 ) is pressed, so that by the constant contact between the rolling elements and the raceways ( 7 . 5 ) Slip is avoided. Radial rolling bearing ( 1 ) according to claim 1, characterized in that the rolling elements as in the disc cage ( 11 ) arranged cylindrical rollers ( 10 ) are formed, which at its in the outer bearing ring ( 2 ) arranged annular groove ( 19 ) facing circumferential surface is slidably guided. Radial rolling bearing ( 1 ) according to claim 2, characterized in that the peripheral surface of the disc cage ( 11 ) a ring-like exemption ( 21 ), which in the region of the pockets ( 13 ) with radial passage holes ( 27 ) is provided. Radial rolling bearing ( 1 ) according to claim 1, characterized in that the pockets ( 13 ) of the disc cage ( 11 ) each with a sickle-like exemption ( 24 ) are provided. Radial rolling bearing ( 1 ) according to claim 1, characterized in that the outer bearing ring ( 2 ) in the region of its lateral surface with a circumferential groove ( 20 ) provided at at least one circumferential location via a radial bore ( 28 ) with the disc cage ( 11 ) receiving annular groove ( 19 ) connected is. Radial rolling bearing ( 1 ) according to claim 1, characterized in that the outer bearing ring ( 2 ) is formed in two parts, with both ring halves ( 14 . 15 ) at at least one circumferential location, each with a recess ( 18 ) are provided, in which a holding element ( 17 ) is used.