Roller bearing

Abstract: A rolling bearing, comprising two bearing rings (10, 11), a number of roller elements (12) arranged between the bearing rings (10, 11) and a retainer (13) for the roller elements (12). The retainer (13) contains several segments (14), whereby a roller element (12) is guided between opposed surfaces (16, 17) on two adjacent segments (14).

Description: The present invention relates to a roller bearing of the type defined in the preamble of claim 1. Segmented roller retainers are described in US,A,3966284, US-A-4056293, US-A-4235487 and US-A-4239304. In these previously known designs the segments are mutually connected. FR-A-1307028 discloses a bearing according to the preamble of claim 1,wherein the retainer segments are not interconnected. The bearing is a cylindrical roller bearing which means that a desire to avoid the creation of radially inward force components on the segments is no critical design parameter. FR-A-1490628 discloses a bearing according to the preamble of claim 7, wherein the retainer segments are freely movable in the axial direction until they abut the inner or outer ring. The retainer segments have no base portions which cooperate with the end surfaces of the rollers. FR,A,1490628 discloses a cylindrical or taper roller bearing wherein the retainer segments are not held in force equilibrium in all directions. The present invention is generally applicable on roller bearings but in the first hand is intended for use with spherical roller bearings, in particular spherical roller thrust bearings. Normally spherical roller thrust bearings are manufactured with two different retainer designs, either with a retainer of pressed sheet-metal or with a solid retainer, which is guided by a sleeve mounted in the hole of the shaft washer. The present invention intends, when applied to spherical roller thrust bearings, to offer an alternative to the last mentioned retainer design. In this design the pockets are bored in the solid retainer ring,which puts great demands on the machine equipment from operational and capacity aspects. An object of the present invention is to provide a segmented retainer ring for large bearings, which is relatively simple and inexpensive to produce. Another object of the invention is to provide a segmented retainer ring, which can be given close tolerances at the contact points with the roller elements. A further object of the invention is to provide a segmented retainer ring, in which a favourable force co-operation between retainer ring and roller elements is obtained. Another object of the invention is to provide a segmented retainer ring, where the retainer construction keeps together the set of rollers and the inner ring when the bearing is handled. These and other objects have been achieved by the invention obtaining the features stated in the following patent claims. The invention will be described in the following with reference to the accompanying drawing in which an embodiment is shown in the object of exemplification. This embodiment is only intended to illustrate the invention, which can be modified within the scope of the claims. In the drawings Fig. 1 shows in section an embodiment of a roller bearing according to the invention. Fig. 2 shows in an enlarged scale a section corresponding to the section in Fig. 1 with a roller and an adherent segment. Fig. 3 shows a perspective view of two adjacent segments and a roller. Fig. 4 shows a top view of the segments and the roller in Fig. 3. A spherical roller thrust bearing according to the invention comprises an outer ring or shaft washer 10, an inner ring or casing washer 11, and a number of rollers 12 arranged between the rings. A sleeve 15 which is mounted in the ring 10 is arranged to guide a segmented retainer 13 for the rollers 12. Each roller 12 includes a peripheral surface 12A defining a roller axis 12D, and radially inner and outer end surfaces 12B, 12C. The retainer 13 comprises a number of retainer segments 14, each segment comprising a base portion or shoe 24 and an elongate element or bar 25 projecting therefrom. Lateral surfaces 16, 17 of the bar 25, which face in opposite circumferential directions, are intended to fit against respective ones of two adjacent rollers 12. The shoe 24 includes ears 24A which project laterally relative to the surfaces 16, 17 of the bar 25. Each ear 24A includes a generally radially facing surface 23 which extends laterally beyond a respective surface 16 or 17 of the bar 25. According to one aspect of the invention, the rollers 12 are in the form of spherical roller type thrust bearings. That means that the peripheral surface 12A of the roller comprises a segment of a circle when the roller is viewed in axial cross-section (i.e. axially with reference to the roller axis 12D). Each roller 12 is arranged to be guided between the opposed surfaces 16, 17 of two circumferentially adjacent segments 14. The adjacent segments are non-interconnected and provided with a mutual play 18 in the circumferential direction of the bearing. Thus, while the segments 14 are indeed guided by the sleeve 15, they are movable with respect to each other in the circumferential direction of the bearing. In accordance with the present invention, the segments transmit rolling forces from a roller 12 to an adjacent roller 12 without appreciably loading the segments 14 with radial force components that must be absorbed by the relatively weak sleeve 15. This is achieved in that the surfaces 16, 17 are configured to make point contact with the rollers 12 at a location on the curved outer periphery thereof wherein a force transmitted from a segment 14 to an adjacent roller 12 excludes a radially force component which would load the sleeve 15. The creation of such point contact between the segment surfaces 16, 17 and the roller peripheries is preferably achieved by shaping the contact regions 19 as outward projections of the surfaces 16, 17. It would be desirable that the force be transmitted precisely in a tangential direction T (with reference to the axis of rotation A). That tangential force shown in Fig. 4 is achieved by creating the point contact at an optimum location 19' shown in Fig. 2. However, it is preferable to ensure that no radial force component will result from slight manufacturing inaccuracies, by instead situating the point contact location 19 slightly outwardly (with reference to the axis 12D of the roller) of the optimum point 19' (see Fig. 2). That may result in the transmission of an outward force F (Fig. 2), but ensures that the relatively weak sleeve 15 will not be radially loaded. The optimum point 19' is normally situated at a position corresponding to the shortest spacing between the adjacent rollers. By displacing the contact point slightly outwardly thereof to point 19 (as depicted in Fig. 2), there is achieved not only the above-discussed assurance against radial inward loading of the sleeve 15, but also a relationship wherein the contact points will cause the rollers to hang upon the segments during operation of the roller bearing as well as when the ring 11 has been removed (thereby facilitating the handling of the bearing). Thus, according to another aspect of the invention, likewise applied to spherical roller thrust bearings, a segmented retainer ring is provided of such design that the roller set and the inner ring are held together as a unit when the outer ring is dismounted. This is achieved by arranging the segments 14 such that the shoes 24 bear against a radial support surface 15A on the sleeve 15 and by making the lateral surfaces 16, 17 of the bar 25 curved generally in accordance with the curvature of the roller periphery 12A, so that the surfaces 16, 17 on two adjacent bars 25 together form a seat in which a roller 12 is nested. Furthermore, on each of the lateral surfaces 16, 17 the projection 19 is arranged slightly outwrdly of the closest points separating two adjacent rollers 12. As noted earlier, radial and axial forces acting on the sleeve are thus minimized. Satisfactory guiding of the roller 12 is obtained with only one projection on the lateral surfaces 16, 17. In the embodiment shown, however, radially inside the projection 19, two additional projections 20, 21 are arranged on ech of the lateral surfaces to make point contact with the peripheral surface 12A of a roller 12. In the illustrated embodiment, moreover, two additional projections 22 are arranged on each of the lateral surfaces 23 for making point contact with the radially inner end surface 12B of a roller 12. In the illustrated embodiment, the segments 14 are formed in such a way that the bars 25 extend generally radially outwardly from the shoe 24. It is, however, possible to alternatively arrange a sleeve or other suitable support means at the radially outer side of the inner ring 10, whereby the bars on the segments would extend generally radially inwardly from the shoe of such segments. The contact points between a roller and both segments straddling same would, for the above-discussed reasons, be arranged essentially at the closest points of two adjacent rollers. Above invention has been described in connection with spherical roller thrust bearings. Obviously, the invention can be applied on other types of thrust bearings and should also be generally applicable on rolling bearings.

Claims: A roller bearing comprising two bearing rings (10,11) defining a common longitudinal axis (A), a plurality of roller elements (12) arranged between said bearing rings permitting relative rotation between said bearing rings about said axis, and retaining means (13) for circumferentially spacing apart said roller elements, said retaining means comprising a plurality of retainer segments (14), each roller element (12) positioned between circumferentially adjacent ones of said retainer segments (14), said adjacent retainer segments being non-interconnected and spaced circumferentially apart to define circumferential play therebetween permitting said adjacent retainer segments (14) to move circumferentially relative to one another, each of said retainer segments (14) including circumferentially facing surfaces (16, 17) engaging respective roller elements (12) characterized in that each of said retainer segments (14) comprises a base portion (24) and an elongate element (25) projecting from said base portion (24) generally in the axial direction of the roller elements (12), said base portion (24) including two lateral surfaces (23) adapted to engage an end surface (12B) of a roller element (12), each of said circumferentially facing surfaces (16, 17) including means (19) making point contact with a respective roller element (12) for transmitting forces from one of said roller elements (12) to a circumferentially adjacent roller element (12). A roller bearing according to claim 1, wherein said means (19) making point contact with a respective roller element (12) transmits said forces from one roller element (12) to a circumferentially adjacent roller element (12) in a direction which is substantially tangentially oriented with reference to said axis (A). A roller bearing according to claim 1, wherein said means making point contact comprises an outward projection (19) on each of said surfaces (16, 17). A roller bearing according to claim 3, wherein each of said surfaces (16, 17) includes second (20) and third (21) projections spaced radially inwardly from said first projection (19) and each making point contact with a roller element (12). A roller bearing according to claim 4, wherein each of said lateral surfaces (23) includes a fourth projection (22) arranged to make point contact with an end surface (12B) of a roller element (12). A roller bearing according to claim 1, wherein said circumferentially facing surfaces (16, 17) of said segments (14) are curved in complementary fashion relative to said peripheral surfaces (12A) of said roller elements (12). Spherical roller bearing, in particular spherical roller thrust bearing, comprising two bearing rings (10, 11) a plurality of spherical roller elements (12) arranged between said bearing rings for permitting relative rotation between said bearing rings about an axis (A), and retaining means (13) for circumferentially spacing apart said roller elements (12), said retaining means (13) comprising a plurality of retainer segments (14), each roller element (12) positioned between circumferentially adjacent ones of said retainer segments (14), each of said retainer segments including circumferentially facing first surfaces (16, 17) engaging respective roller elements (12), said roller elements (12) having generally convex second surfaces when seen in the axial direction of the rollers, characterized in that said first surfaces (16, 17) include means (19) making point contact with said roller elements (12), said means (19) being situated substantially at a location, when seen in the axial direction of the rollers, where the circumferential spacing between adjacent roller elements is minimum so as to ensure that no substantial radial pressure forces are loaded on the retainer segments (14). A spherical roller bearing according to claim 7, wherein said means (19) defining point contact between said circumferentially facing surfaces (16, 17) and said roller elements (12) are spaced slightly outwardly from a location where the circumferential spacing between adjacent roller elements is minimum, whereby said segments (14) hang upon said roller elements (12). A retainer segment adapted for use in a segmented retainer of a spherical roller thrust bearing comprised of a pair of bearing rings (10, 11) and spherical roller elements (12) disposed between said bearing rings, characterized in that said retainer segment comprises a base portion (24) and a bar (25) projecting laterally therefrom, said bar (25) including two oppositely facing surfaces (16, 17) for supporting adjacent ones of the roller elements (12), each of said surfaces of said bar including at least one projection (19) for contacting a roller element (12) by means of point contact. A retainer segment according to claim 9, wherein said surfaces (16, 17) are curved in a manner generally corresponding to a curved outer periphery of a spherical roller (12), said base portion (24) including lateral surfaces (23) extending laterally relative to said oppositely facing surfaces (16, 17) of said bar (25). A retainer segment according to claim 9, wherein said projections constitute first projections (19) on said oppositely facing surfaces (16, 17) situated at a location corresponding to a minimum spacing between adjacent roller elements (12), each of said oppositely facing surfaces further including second and third projections (20, 21) situated closer to said base portion (24) than said first projection said base portion (24) including two lateral surfaces (23) extending laterally of said oppositely facing surfaces (16, 17), each of said lateral surfaces including a fourth projection (22) adapted to engage an end surface of a roller element (12).

Inventors: AMEN RAFAEL, GOERANSSON BO, GUSTAVSSON ROLF, NYMAN NILS, AMEN, RAFAEL, GOERANSSON, BO, GUSTAVSSON, ROLF, NYMAN, NILS, Göransson, Bo
Applicants: SKF AB, AB SKF
Application year: 1990
Main classification: F16C33
IPC codes: F16C23, F16C19, F16C33