The invention concerns a roller bearing cage having at least U-shaped-defined pockets for roller bodies.
A roller bearing cage is known, e.g., from DE 79 35 982 U1, which is comprised of two side parts and a plurality of bridge parts that are separately manufactured and connected with the side parts by welding or the like, wherein the bridge parts form pockets between them for accommodating the roller bodies. The side parts and bridge parts are manufactured from flat or profile-milled wire and the bridge parts are stamped to form the slip surfaces for the roller bodies.
It is an object of the present invention to provide an improved roller bearing cage having at least U-shaped-defined pockets for roller bodies.
The object is achieved by the subject matter of claim 1. Advantageous embodiments are described in the dependent claims.
According to claim 1, a roller bearing cage having at least U-shaped-defined pockets for roller bodies includes the following features:
At least one annular circumferential element, which is formed with at least three radial indentations or bulges distributed in the circumferential direction, whose inner or outer surfaces serve as guide surfaces for the cage, and
bridge elements are attached to the circumferential element in a material-bonded manner, wherein each one of the pockets extends between two adjacent bridge elements.
The invention is based upon the recognition, inter alia, that it is effective, in particular when the cage provides a shoulder guidance, to bridge a radial distance between the abutment of a surface of the circumferential element on an inner- or outer shoulder and/or an inner ring- or outer ring collar on the one side and a roller body abutment surface on the bridge elements on the other side. Due to the indentations or bulges according to the invention, the bridging is advantageously achieved with a very low material usage, as compared to an unbulged, circular-annular-like circumferential element. In particular, by welding the bridge elements onto the circumferential element, the similarly-formed bridge elements can be produced in a simple and cost-effective manner by cutting an appropriately-profiled bar or strip material, preferably made of steel, into sections. Relative to roller bearing cages that are machined from a hollow cylinder-like pipe, the roller bearing cage according to the present invention naturally also offers the advantage that no material waste results from a machining, in particular, of the cage pockets, and thus a material savings advantageously results as compared to such a machining method.
In an advantageous embodiment, the circumferential element on the one hand and the bridge elements on the other hand are formed with different properties. In this case, it is advantageously possible to pair different materials and, depending on the application, e.g., to produce less heavily-loaded elements from cheaper materials. Further, it is also possible to form one of the elements from a heat-treated steel for high wear resistance and to leave other elements untreated, e.g., for a high ductility.
In a further advantageous embodiment, it is possible to form at least one of the elements in a coated manner. In this case, due to the roller bearing cage being formed from the circumferential and bridge elements, it is much simpler and thus also more cost-effective to perform the coating of individual elements, e.g., the bridge elements. The same applies to a further advantageous embodiment, in which, e.g., ship-hull-like and/or droplet-shaped impressions are provided on the surfaces of the bridge elements that face the roller bodies and the impressions function as lubricant pockets.
Further advantages, features and details of the invention are derivable from the exemplary embodiments of the invention described in the following with the assistance of the Figures.
As an exemplary embodiment of the invention,
In another embodiment, the bridge elements 14 naturally could also be welded in the middle portion of bulges, which are bulged farther radially outward, or also on the outer surface side, whereby a still larger radial distance can be bridged between the guide surface and the side surfaces of the bridge elements 14 provided for contacting the rolling surfaces. The connecting portions on the circumferential elements for the bridge elements 14 can be formed in a manner fitted to the bridge elements 14 in accordance with DE 10 2007 202 113 A1. The attachment of the bridge elements 14 to the inner surface of the circumferential elements offers the completely obvious advantage that these bridge elements are inherently secured, in a manner of speaking, by the circumferential elements against the centrifugal force arising during operation of the cylindrical roller bearing due to the rotating cage. For an outer rim guidance, the preceding description applies inversely in a corresponding manner with radially-outwardly-bulging bulges of an undulated circumferential element.
The elements 11 and 14 are produced from an iron material, in particular from a steel wire. In other embodiments, however, other materials could be utilized and, instead of welding, soldering or adhesive could be applied. Furthermore, the bridge elements 14, in particular, can also be formed with a coating in order to achieve a particular sliding behavior, in particular in the area of its contact surfaces with the roller bodies.
Finally, the preceding description for a one-row cylindrical roller radial bearing as an example of a window-type cage is also applicable to other roller bearings, in particular tapered roller bearings, as well as also to spherical bearings, CARB-bearings and also barrel-shaped bearings, but also to bearings having comb-like cages, to roller bearings having multiple roller rows and also to axial bearings.
Number | Date | Country | Kind |
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20 2008 014 280.6 | Oct 2008 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2009/007540 | 10/21/2009 | WO | 00 | 9/28/2011 |