GB2378988A

GB2378988A - Radial-axial rolling bearing

Info

Publication number: GB2378988A
Application number: GB0120566A
Authority: GB
Inventors: Thomas Dittenhoefer
Original assignee: INA Waelzlager Schaeffler OHG
Current assignee: INA Waelzlager Schaeffler OHG
Priority date: 2001-08-23
Filing date: 2001-08-23
Publication date: 2003-02-26
Also published as: FR2829199B1; FR2829199A1; GB0120566D0

Abstract

A radial-axial rolling bearing, having an L-shaped arrangement of components so as to increase stiffness against canting, comprises a radial bearing 1 and axial bearings 2, 3 having a common axis of rotation (Fig 1, 18.). Radial bearing 1 has an inner ring 20 (formed from two component rings 21, 22), an outer ring 4 arranged coaxially therewith (between which rolling bodies 9 roll to absorb radial forces) and cylindrical rolling bodies 10,11 which are guided in individual and spring arranged segments (26, Fig 4.) cages 12, 13. The cages are arranged on the two sides (with their raceways formed on one side by the flanks of outer ring 4 and on the other side by race rings 6, 8, one of which is connected to inner ring 5) so as to absorb axial forces. Rolling bodies 10, 11 of bearings 2, 3 are guided by rim 19 which is disposed either on outer ring 4 or race ring 6, 8. Inner ring 20 is machined as a single component and is then split in to two component rings 21, 22 which are held together with fixing screws.

Description

RADIAL-AXIAL ROLLING BEARING Field of the invention This invention relates to a radial-axial rolling bearing, with an inner ring and an outer ring arranged coaxially therewith, between which rolling bodies roll to absorb radial forces, and with cylindrical rolling bodies guided in cages arranged on the two sides to absorb axial forces, with their raceways formed on one side by the flanks of the outer ring and on the other side by respective race rings.

Background of the invention Such a radial-axial rolling bearing acting on both sides is shown on page 136 of the INA catalogue of rolling bearings 305. This bearing has an inner ring and an outer ring arranged coaxially therewith, so that a circular set of cylindrical rollers can roll between them on corresponding raceways. An axial bearing is arranged on each of the right and left sides, with their cylindrical rolling bodies guided in cages. The inner ring of the radial bearing is formed in one piece with a race ring, i. e. it has an L-shaped profile. The other race ring of the second axial bearing is attached to the L-shaped component by means of fixing screws, the parting plane between the two parts being disposed in the extension of the radial plane of the running surface of one axial bearing.

A disadvantage of this is that the cylindrical rolling bodes of the two axial bearings are guided by the bearing cage. Accordingly higher sliding components are involved, caused by the rolling of the two axial bearings, which have a disadvantageous effect on the running of the combined bearing arrangement. It is a further disadvantage with this bearing arrangement that, because of its construction, it has too small a stiffness in relation to canting. This is caused by the individual race ring, which is fixed on the component consisting of the inner ring and other race ring.

Summary of the invention The invention is based on the object of developing a combined radial-axial rolling bearing of the type specified which exhibits improved rolling behaviour and which has improved stiffness.

This object is met in accordance with the invention according to the characterizing part of claim I in that the cylindrical rolling bodies of the axial bearings are each guided by a rim which is disposed either on the outer ring or on the race ring.

The sliding components in the rolling process are reduced by the rim guiding according to the invention of the axial circular sets of cylindrical rollers, consisting of axial cages with cylindrical rollers, since the rim contact is better in terms of friction than guiding the cylindrical rollers by the cage webs according to the prior state of the art. The cage largely serves merely to maintain the spacing of the cylindrical rollers or to secure the position during transport and when stationary. Coarse guiding of the cylindrical rolling bodies by the cage takes place in the zone freed from stress.

Further advantageous arrangement of the invention are described in dependent claims 2 to 10.

Thus, according to claim 2, it is provided that the inner ring is formed from two component rings, which are connected in one piece with the race rings, wherein the parting plane between the component rings is disposed in the raceway region of the radial bearing. The parting plane is advantageously disposed in the centre of the raceway region of the radial bearing, in accordance with claim 3.

The stiffness against canting of the whole bearing unit is substantially increased by this Lshaped formation of the assembled components. The L-shaped components associated with one another in mirror-image relationship are centred by the cylindrical rollers of the radial bearing, i. e. radial offset of the two components lying opposite one another is thus ruled out. This is prevented by the parting plane being disposed in the raceway region of the radial bearing. A further advantage of this design it that the level of manufacture is reduced, i. e. the bearing unit consists of fewer parts.

In this connection it has proved to be advantageous if the inner ring, including the associated race rings is initially machined as a unitary component and is split into the two component rings after being finished, in accordance with claim 4. The common machining ensures that no different tolerances can arise, in contrast to individual machining in the raceways and fixing bores.

It is seen from claim 5 that the component rings are held together by fixing screws. Supply as a complete component can be effected in this way, where the prestress desired by the customer can already be set by the manufacturer. This is realised by different thicknesses of the components involved or by rolling bodies picked by size.

According to another feature of the invention according to claim 6, one of the race rings is to be connected to the inner ring. The parting plane is disposed in this case outside the raceway region of the radial bearing, i. e. it is located at the junction with the axially extending part of the L-shaped component in the region of the outer raceway of the axial bearing.

According to a further additional feature of the invention according to claim 7, it is provided that the cage of the axial bearing is composed of individual segments abutting one another in the circumferential direction, each receiving a cylindrical rolling body. This cage variant can always be used to particular advantage when modified size relationships of the races or the race rings are necessary with unchanged size relationships of the cylinder rollers. If the cage is composed of a plurality segments, it proves to be advantageous if the segments each posses arcuate boundary lines opposite in a circumferential direction at least in a part region of their radial extend, in accordance with claim 8, so that a contact point is formed between two adjacent segments, which lies in the region between the pitch circle and rim. This contact point between two adjacent segments then shifts outwards or inwards, depending on whether the race rings increase or decrease in their diameter. According to another additional feature it can be useful in this case if a spring means is arranged between two adjacent segments, according to claim 9.

Finally, according to claim 10, it is provided that the segments have two spaced bumps on their radially inner side, spaced from one another in the circumferential direction. Coarse guiding of the individual cage segments with their rolling bodies is achieved by these two radial contact points.

The invention will be explained in more detail with reference to the following embodiments.

Brief description of the drawings These show: Figure I is a longitudinal section through a radial-axial bearing unit according to the invention, Figure 2 is an enlarged showing of a detail according to Figure 1, Figure 3 is a half section through a bearing according to the invention and Figure 4 shows a portion of a plan view of individual cage segments.

Detailed description of the drawings The combined radial-axial rolling bearing shown in Figure I consists of the radial bearing 1 and the axial bearings 2 and 3 arranged on the two sides, which have the common axis of rotation 18. The radial bearing I comprises the inner ring 5, with which the outer ring 4 is coaxially arranged, so that raceways not specifically referenced are formed, on which the cylindrical rollers 9 roll. The outer ring 4 is provided with fixing bores 14. The inner ring 5 of the

radial bearing I forms a unit with the race ring 6 of the axial bearing 3, i. e. it is of L-shape and comprises the axially extending part 7, which carries the inner raceway for the cylindrical rollers 9. The axially extending part 7 of the inner ring 5 is provided with rims 32 and 33, which guide the cylindrical rollers 9 in the axial direction. The race ring 8 for the other axial bearing 2 adjoins the end face of the axially extending part 7 of the of the L-shaped inner ring 6, a parting plane 15 being formed between the two parts. This extends in a radial plane with the outer raceway for the cylindrical rollers 10 formed by the race ring 8. Raceways result in this way for the two axial bearings 2 and 3, which are formed on the one side by the faces flanks facing away from each other of the outer ring 4 of the radial bearing I and on the other side by the faces directed towards each other of the two race rings 6 and 8. The cylindrical rollers 10 and 11 fitted in cages 12 and 13 roll on these raceways, not specifically referenced. The outer ring 4 of the radial bearing I is provided with a rim 19 on each of its opposite flanks, which takes care of the radial guiding of the circular sets of axial cylindrical rollers formed by the cylindrical rollers 10,11 and cages 12,13.

Improved friction properties of the two axial bearing 2,3 are obtained through this modified guiding, since the sliding part of the rolling bodies 10,11 becomes less. The two cages 12,13 are in the form of disc cages, i. e. they merely separate the cylindrical rollers 10,11 from one another.

Both the race ring 8 and the inner ring 5 are provided with through fixing bores 16.17, through which fixing screws, not shown, are passed to take care of secure assembly of the overall arrangement. The bearing is as a rule supplied with the prestress required by the customer set by the manufacturer by the axial width of the race ring 6, outer ring 4, race disc 8 and radial extent of the outer ring 4 and inner ring 5 or by picking sizes of cylindrical rollers 10,11, 9.

The radial guiding of the axial bearing 2 can be seen to a larger scale in Figure 2. The cylindrical rollers 10 guided in the cage 12 bear radially outside on the rim 19 of the bearing outer ring 4. The cage 12 is supported in the unloaded state of the axial bearing 2 with its radially inside end on a projection, not referenced, of the axially extending part 7 of the inner ring 5.

A variant of the radial-axial rolling bearing according to the invention which is especially stiff against canting is shown in Fig. 3. The radial bearing I comprises an inner ring 20 which is again composed of the two component rings 21 and 22. The component rings 21, 22 are of Lshape and comprise the axially extending parts 23,24, which are again connected to the race rings 8,6. In this way the parting plane 35 is formed to lie in the raceway region of the cylindrical rollers 9, so that radial offset of the two component rings 21, 22 relative to one another is prevented.

Figure 4 is a plan view of the axial bearing 2,3, wherein its cylindrical rollers 10,11 are fitted in segments 26. Each individual segment 26 has arcuate bounding lines 27,28 defined by

the radius R, opposite one another in the circumferential direction, so that the contact point 29 is formed by contact of the arcuate bounding line 27 with the arcuate bounding line 28 in the case of two adjacent segments 26. Figure 4 further shows that the cylindrical rollers 10,11 are guided by the rim 19 of the bearing outer ring 4 at their radially outer end faces. The segments 26 have two bumps 30 and 31 spaced in the circumferential direction on their radially lower ends, with which they are supported in the non-stressed state on the component rings 21,22. The contact point 29 is arranged approximately in the region of the pitch circle. Depending on the selected dimensional relationships, i. e. with changing radial diameter of the two race discs 6,8, the contact point 29 shifts either to the outside or the inside. If the race rings 6,8 and the outer ring 4 increase in their radial extent, the contact point 29 moves radially outwards and vice versa. This ensures that race rings 6,8 differing in radial extent can be used with use of cylindrical rollers 10,11 of the same size and the same segments 26.

Claims

CLAIMS !. A radial-axial rolling bearing, with an inner ring (5,20) and an outer ring (4) arranged coaxially therewith, between which rolling bodies (9) roll to absorb radial forces, and with cylindrical rolling bodies (10, 11) received in cages (12,13) arranged on the two sides to absorb axial forces, with their raceways formed on one side by the flanks of the outer ring (4) and on the other side by respective race rings (8, 6), characterized in that the cylindrical rolling bodies (10, 11) of the axial bearings (2,3) are each guided by a rim (19) which is disposed either on the outer ring (4) or on the race ring (8,6).
2. A radial-axial rolling bearing according to claim 1, characterized in that the inner ring (20) is formed from two component rings (21,22), which are connected in one piece with the race rings (8, 6), wherein a parting plane (25) between the component rings (21,22) is disposed in the raceway region of the radial bearing (1).
3. A radial-axial rolling bearing according to claim 2, characterized in that the parting plane (25) is disposed in the centre of the raceway region of the radial bearing (1).
4. A radial-axial rolling bearing according to claim 2, characterized in that the inner ring (20) is initially machined as a unitary component and is split into the two component rings (21,22) after being finished.
5. A radial-axial rolling bearing according to claim 2, characterized in that the component rings (21, 22) are held against one another by fixing screws.
6. A radial-axial rolling bearing according to claim I, characterized in that one of the race rings (6,8) is connected to the inner ring (5).
7. A radial-axial rolling bearing according to claim I, characterized in that the cage of the axial bearing (2,3) is composed of individual segments (26) abutting one another in the circumferential direction, each of which receives a cylindrical rolling body (10, 11).
8. A radial-axial rolling bearing according to claim 7, characterized in that the segments (26) have arcuate bounding lines (27,28) opposite in the circumferential direction in at least a

<Desc/Clms Page number 7>

partial region of their radial extent, so that a contact point (29) is formed between two adjacent segments (26) which lies in the region between pitch circle line and rim (19).
9. A radial-axial rolling bearing according to claim 7, characterized in that a spring means is arranged between two segments (26) adjacent one another.
10. A radial-axial rolling bearing according to claim 7, characterized in that the segments (26) have two bumps (30, 31) spaced from one another in the circumferential direction on their radially inner sides.