Radial roller bearing

A radial roller bearing comprises a smooth cylindrical outer ring inserted in a housing with a roller race arranged in the outer ring. The roller race is formed by a plurality of roller-shaped rolling elements inserted in a bearing cage, which holds said rolling elements evenly spaced in a circumferential direction. The rolling elements roll off an outer raceway formed by the inner shell surface of the outer ring, and off an inner raceway formed by the outer shell surface of a shaft to be mounted, or formed by a smooth cylindrical inner ring fitted onto the shaft. The axial guidance of the roller race is accomplished by way of two separate flanged rings abutting the axial sides of the outer ring which, together with the outer ring are axially fixed in place by way of safety elements engaging with circumferential grooves in the housing. The safety elements for the flanged rings and the outer ring, and the flanged rings are fixedly connected.

This application is a National Phase of PCT Application No. EP2012/051862 filed Feb. 3, 2012, which in turn claims benefit of German Patent Application No. 10 2011 007 458.9 filed Apr. 15 2011.

FIELD OF THE INVENTION

The invention concerns a radial roller bearing, which bearing can be used particularly advantageous as a movable bearing for high radial forces and low axial forces for the mounting of shafts and rotating parts.

BACKGROUND OF THE INVENTION

It is general knowledge in the field of rolling bearings technology that shafts and rotating parts, are mostly mounted at two mounting points configured as a fixed bearing and a movable bearing because, in this way, manufacturing tolerances and length variations caused by thermal expansions between the shaft and a housing or between an axle and the rotating part can be compensated for without additional clamping forces acting on the bearing. The fixed bearing that is fixed in axial direction takes up, in addition to its radial force fraction also all axial forces in both directions, whereas the movable bearing transmits only its radial load fraction because it is not fixed in axial direction and therefore, as a result, cannot take up any axial force. The compensation of manufacturing tolerances and thermal expansions is thus effected exclusively through the movable bearing, more specifically at the two seating point of the inner ring, at the seating point of the outer ring of in the bearing itself.

A generic radial rolling bearing for a typical movable mounting of a radially highly loaded shaft is known, for example, from DE 2 931 348 A1. This movable bearing configured as a radial cylindrical roller bearing is made up substantially of a smooth cylindrical outer ring which is inserted into a housing and of a roller crown ring arranged in this outer ring, this crown ring being formed by a plurality of rolling elements which are inserted into a bearing cage and retained by this uniformly spaced in peripheral direction. The rolling elements configured as cylindrical rollers roll on an outer raceway formed by the inner peripheral surface of the outer ring and on an inner raceway formed by the outer peripheral surface of a smooth cylindrical inner ring which is slipped onto the shaft, which inner raceway is formed in other applications also by the outer peripheral surface of the shaft itself. In addition, for an axial guidance of the roller crown ring, two separate flanged disks are arranged on the axial sides of the outer ring, which flanged disks, together with the outer ring, are fixed in place against an axial displacement, on one side by a snap ring that engages into a circumferential groove in the housing and, on the other side by a fixing element configured as an adjustable tension ring.

Further, another generic radial roller bearing configured as a double row needle roller bearing for a movable mounting of a radially highly loaded rotating part is known from a catalogue of the applicant, October 2008 Edition, page 742, under the designation NAO..-ZW-ASR1. In this needle roller bearing likewise made up substantially of a smooth cylindrical inner ring that is slipped onto an axle, a roller crown ring arranged on the inner ring and a smooth cylindrical outer ring that is inserted into a rotating part, the axial guidance of the roller crown is, however, effected through two separate flanged disks that bear against the axial sides of the inner ring, which flanged disks, together with the inner ring, are fixed in place in axial direction by two fixing elements that are configured as snap rings and engage into circumferential grooves in the axle.

A drawback of both the aforesaid radial roller bearings is, however, that the axial fixing of the outer and the inner ring as also of the adjoining flanged disks in the housing or on the axle is effected through two additional components that, in the case of large bearing piece numbers, are delivered by the bearing manufacturer in separate magazines, in addition to the flanged disks that are likewise already delivered in a loose state. The, as it is high complexity and costs of assembly of such radial roller bearings are thus further increased by the laborious step of removing the fixing elements out of the magazine and through the necessary use of separate assembly tools for these fixing elements, so that such bearings have proved to be extremely uneconomical.

OBJECT OF THE INVENTION

Starting from the aforesaid drawbacks of the known state of the art, the object of the invention is therefore to conceive a radial roller bearing of the two initially described types, the assembly of which is simplified and possible without the use of separate assembly tools and which is therefore characterised by low assembly costs.

DESCRIPTION OF THE INVENTION

This object is achieved through a radial roller bearing with fixing elements for flanged disks and for an outer and inner ring, as well as the flanged disks configured as a fixedly connected assembly.

The invention is therefore based on the not very obvious perception that it is possible, through a suitable form of integration of the fixing elements with the flanged disks, to minimise on the one hand the number of components and thus the delivery quantity required for such radial roller bearing from the manufacturer and, on the other hand, at the same time, to considerably reduce the complexity and costs of assembly because the step of removing the fixing elements out of the magazine can be omitted and insertion or placement of the flanged disks into a housing or on an axle can be performed in one single work step without separate assembly tools.

Preferred embodiments and advantageous developments of the two types of a radial roller bearing configured according to the invention will be described herein.

In a first embodiment of a radial roller bearing, the fixing elements are formed by two spring rings with an elliptical shape, the transverse axes of which are smaller and the longitudinal axes of which are larger than the diameter of the flanged disks, the spring rings being fixed with their smaller diameter regions on the outer sides of the flanged disks and having an elastically inwards yielding configuration in their larger diameter regions. Thus, the elliptical spring rings are fixed with their smaller diameter regions in such a way on the flanged disks that their larger diameter regions protrude slightly beyond the flanged disks. During the assembly of the flanged disks, the spring rings are deformed by force of hand onto the diameter of the flanged disks in order to be able to insert the flanged disks into the bearing bore of the housing and to push them in this bearing bore up to the outer ring. In the end position of the flanged disks, the larger diameter regions of the snap rings then spring automatically into a circumferential groove in the housing, so that both the flanged disks as well as the outer ring of the radial roller bearing are fixed in axial direction.

In a further embodiment of the radial roller bearing, the fixing elements are formed respectively by two shortened semi-segments of two spring rings having an elliptical shape that are split longitudinally centrally, the transverse axes of which are smaller and the longitudinal axes of which are larger than the diameter of the flanged disks, the semi-segments being fixed respectively with their central regions on the outer sides of the flanged disks and having an elastically inwards yielding configuration in their end regions. This form of embodiment thus differs from the first form of embodiment by the fact that the elliptical spring rings are split along their longitudinal axes into two semi-segments that are slightly shortened in their respective ends but protrude slightly beyond the flanged disks with these ends. The assembly of the flanged disks configured with these fixing elements is then performed in the same manner as in the first form of embodiment till the end regions of the semi-segments yield automatically inwards into a circumferential groove in the housing. Alternatively, it would however also be possible, in place of the semi-segments of elliptical spring rings, to fix respectively two straight spring rods in such a way with their central regions on the outer sides of the flanged disks that the end regions of the spring rods protrude slightly beyond the outer diameter of the flanged disks and likewise have an elastically inwards yielding configuration.

In another embodiment of a radial roller bearing according to the invention,  the fixing elements are formed by two respective parallel spring wire segments arranged in a secant-like relationship to the inner diameter of the flanged disks, which spring wire segments are fixed with their ends on the outer sides of the flanged disks and are configured to yield elastically outwards in their central regions. Because the inner diameter of the flanged disks corresponds approximately to the diameter of the radial roller bearing, this means that the distance between the spring wire segments is smaller than the diameter of the axle and that through their central regions, the spring wire segments narrow the bores in the flanged disks partially. During assembly of the flanged disks, these spring wire segments are then likewise widened by force of hand to the diameter of the axle in order to be able to push the flanged disks onto the axle and to displace them on the axle up to the inner ring of the radial roller bearing. In the end position of the flanged disks, the spring wire segments then yield automatically elastically into a circumferential groove in the axle, so that both the flanged disks as well as the inner ring of the radial roller bearing are fixed in axial direction. In place of the fixing of the spring wire segments with their ends on the outer sides of the flanged disks, it is likewise conceivable to fix them only with one end on the outer sides of the radial roller bearing so as to enhance their elasticity.

In another embodiment of the radial roller bearing configured according to the invention, the fixing elements are formed by two respective parallel spring wire segments arranged in a secant-like relationship to the inner diameter of the flanged disks, which spring wire segments are fixed with their ends on the outer sides of the flanged disks and the central regions of the spring wire segments are cut apart and configured to yield elastically outwards. This form of embodiment differs from the aforesaid form of embodiment above all by the fact that each spring wire segment is additionally split longitudinally centrally into two semi-segments in order to enable the use of stiffer spring wire segments and to thus enhance their elasticity. The assembly of the flanged disks configured with such fixing elements is then performed in the same manner as in the aforesaid form of embodiment till the spring wire segments yield automatically inwards into a circumferential groove in the axle.

Finally, in a proposed feature for all the forms of embodiment of both types of radial roller bearings configured according to the invention, the fixing of the fixing elements on the outer sides of the flanged disks can be performed either by fusion of materials through welding, soldering or gluing points, or by positive engagement through stampings that are coped out of the flanged disks and surround the fixing elements. For these stampings for each fixing point, two metal strips are coped out of the flanged disks in such a way that the distance between these strips corresponds to the width of the fixing element and the strips project at a right angle from the flanged disks. The fixing element is then placed between these metal strips and, in a last step, the metal strips are bent around the fixing elements.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1shows a schematic representation of a first type of a radial roller bearing1which is made up substantially out of a smooth cylindrical outer ring3which is inserted into a housing2and of a roller crown ring4which is arranged in this outer ring3. This roller crown ring4is formed by a plurality of roller-shaped rolling elements6which are inserted into a bearing cage5and retained uniformly spaced in peripheral direction by the cage5. These rolling elements6roll on an outer raceway8formed by the inner peripheral surface7of the outer ring3and on an inner raceway12formed by the outer peripheral surface9of a smooth cylindrical inner ring11which is slipped onto a shaft10. It is to be seen clearly that the axial guidance of the roller crown ring4is accomplished through two separate flanged disks15,16that bear against the axial sides13,14of the outer ring3, which flanged disks15,16together with the outer ring3are fixed in axial direction by fixing elements19,20which engage into circumferential grooves17,18in the housing2, which fixing elements19,20and flanged disks15,16, are configured according to the invention as a fixedly connected assembly.

It can be further seen inFIG. 2that the fixing elements19,20in a first form of embodiment of the radial roller bearing1according to the invention are formed by two spring rings21,22of elliptical shape which are smaller along their transverse axes23,24and larger along their longitudinal axes25,26than the diameter of the flanged disks15,16. The spring rings21,22are fixed with their smaller diameter regions21a,21b,22a,22bby welding, soldering or gluing points39,40,41.42on the outer sides27,28of the flanged disks15,16and are configured in their larger diameter regions21c,21d,22c,22dwhich protrude slightly beyond the flanged disks to yield elastically inwards in such a way that, during assembly of the flanged disks15,16, these regions can be deformed by force of hand onto the diameter of the flanged disks15,16and spring in their end position automatically into the circumferential grooves17,18in the housing2.

In contrast, in the second form of embodiment of the radial roller bearing1configured according to the invention illustrated inFIG. 3, the fixing elements19,20are formed respectively by two shortened semi-segments29,30,31,32of two elliptically shaped and longitudinally centrally split spring rings which, similar to the first form of embodiment, are smaller along their transverse axes23,24and larger along their longitudinal axes25,26than the diameter of the flanged disks15,16. These semi-segments29,30,31,32, too, are fixed their central regions29a,30a,31a,32aby welding, soldering or gluing points39,40,41,42on the outer sides27,28of the flanged disks15,16, and their end regions29b,29c,30b,30c,31b,31c,32b,32care configured to yield elastically inwards in such a way that, during assembly of the flanged disks15,16, these regions be deformed by force of hand onto the diameter of the flanged disks15,16and spring in their end position automatically into the circumferential grooves17,18in the housing2.

Further,FIG. 4shows a schematic representation of a second type of a radial roller bearing1.1which differs from the first type through a reversal of functions and is made up substantially of a smooth cylindrical inner ring3.1which is slipped onto an axle2.1and of a roller crown ring4.1which is arranged on this inner ring3.1. This roller crown ring4.1is likewise formed by a plurality of roller-shaped rolling elements6.1which are inserted into a bearing cage5.1and retained uniformly spaced in peripheral direction by the cage5.1. These rolling elements6.1roll on an inner raceway8.1formed by the outer peripheral surface7.1of the inner ring3.1and on an outer raceway12.1formed by the inner peripheral surface9.1of a smooth cylindrical outer ring11.1which is inserted into a rotating part10.1. It is to be clearly seen that the axial guidance of the roller crown ring4.1is accomplished in this case through two separate flanged disks15.1,16.1that bear against the axial sides13.1,14.1of the inner ring3.1and which together with the inner ring3.1are fixed in axial direction by fixing elements19.1,20.1which engage into circumferential grooves17.1,18.1in the axle2.1, which fixing elements19.1,20.1and flanged disks15.1,16.1, are likewise configured according to the invention as a fixedly connected assembly.

The first form of embodiment of such a radial roller bearing1.1according to the invention shown inFIG. 5is characterised by the fact that the fixing elements19.1,20.1are formed respectively by two parallel spring wire segments33,34,35,36arranged in a secant-like relationship to the inner diameter of the flanged disks15.1,16.1, which spring wire segments are fixed with their ends33a,33b,34a,34b,35a,35b,36a,36bon the outer sides37,38of the flanged disks15.1,16.1through stampings43,44,45,46coped out of the flanged disks15.1,16.1and are configured to yield elastically outwards in their central regions. It is to be clearly seen that the distance of the spring wire segments33,34,35,36from one another is smaller than the diameter of the axle2.1, so that through their central regions33c,34c,35c,36c, the spring wire segments narrow the bores in the flanged disks15.1,16.1partially. During assembly of the flanged disks,15.1,16.1the spring wire segments33,34,35,36are then likewise widened by force of hand onto the diameter of the axle2.1and the flanged disks15.1,16.1are slipped onto the axle2.1, so that, in their end position, the spring wire segments33,34,35,36yield automatically inwards into the circumferential groove17.1,18.1in the axle2.1.

Finally,FIG. 6further shows a second form of embodiment of a radial roller bearing1.1. configured according to the invention, in which the fixing elements19.1,20.1are formed respectively by two parallel spring wire segments33,34,35,36arranged in a secant-like relationship to the inner diameter of the flanged disks15.1,16.1, which spring wire segments, however, are fixed with their ends33a,33b,34a,34b,35a,35b,36a,36bthrough welding, soldering or gluing points39,40,41,42on the outer sides37.1,38.1of the flanged disks15.1,16.1and are additionally cut apart in their central regions33c,34c,35c,36cto enhance their elasticity. The assembly of the flanged disks15.1,16.1configured with these fixing elements19.1,20.1is then performed in the same manner as in the first form of embodiment till the spring wire segments33,34,35,36yield automatically inwards into the circumferential groove17.1,17.2in the axle2.1.

List of reference symbols1Radial roller bearing1.1Radial roller bearing2Housing2.1Axle3Outer ring of 13.1Inner ring of 1.14Roller crown ring of 14.1Roller crown ring of 1.15Bearing cage of 15.1Bearing cage of 1.16Rolling element of 16.1Rolling element of 1.17Inner peripheral surface of 37.1Outer peripheral surface of 3.18Outer raceway for 68.1Inner raceway for 6.19Outer peripheral surface of 10/119.1Inner peripheral surface of 10.1/11.110Shaft10.1Rotating part11Inner ring of 111.1Outer ring of 1.112Inner raceway for 612.1Outer raceway for 6.113Axial side of 313.1Axial side of 3.114Axial side of 314.1Axial side of 3.115Flanged disk on 315.1Flanged disk on 3.116Flanged disk on 316.1Flanged disk on 3.117Groove in 217.1Groove in 2.118Groove in 218.1Groove in 2.119Fixing element for 1519.1Fixing element for 15.120Fixing element for 1620.1Fixing element for 16.121Spring ring21aSmall diameter region of 2121bSmall diameter region of 2121cLarge diameter region of 2121dLarge diameter region of 2122Spring ring22aSmall diameter region of 2222bSmall diameter region of 2222cLarge diameter region of 2222dLarge diameter region of 2223Transverse axis of 2124Transverse axis of 2225Longitudinal axis of 2126Longitudinal axis of 2227Outer side of 1528Outer side of 1629Semi-segment29aCentral region of 2929bEnd region of 2929cEnd region of 2930Semi-segment30aCentral region of 3030bEnd region of 3030cEnd region of 3031Semi-segment31aCentral region of 3131bEnd region of 3131cEnd region of 3132Semi-segment32aCentral region of 3232bEnd region of 3232cEnd region of 3233Spring wire segment33aEnd of 3333bEnd of 3333cCentral region of 3334Spring wire segment34aEnd of 3434bEnd of 3434cCentral region of 3435Spring wire segment35aEnd of 3535bEnd of 3535cCentral region of 3536Spring wire segment36aEnd of 3636bEnd of 3636cCentral region of 3637Outer side of 15.138Outer side of 16.139Welding, soldering or gluing point40Welding, soldering or gluing point41Welding, soldering or gluing point42Welding, soldering or gluing point43Stamping44Stamping45Stamping46Stamping