DE102009042291B4 - component of a rolling bearing - Google Patents

Abstract

Component of a rolling bearing, comprising the following features:- At least one surface area of the component is formed with a surface structure,- the surface structure is regular and characterized by a gap-free coverage of the surface area with a few basic surface elements that are similar to a square, a rhombus and/or a honeycomb, and- in their peripheral areas, the basic surface elements are raised compared to their central areas.

Description

The invention relates to a component of a rolling bearing.

A large number of different surface finishes for rolling bearing components have already been proposed in the state of the art. In particular, with regard to the rolling tracks of rolling bearing components on which rolling elements are intended to roll, manufacturing processes for achieving ever smaller roughnesses have been proposed. However, questions about sufficient lubricant retention in the area of the rolling tracks are often neglected.

For example, from the JP H05 - 240 254 A , the DE 698 09 940 T2 and the US 5 456 538 A Specially designed surfaces of rolling tracks for rolling contact in rolling bearings are known.

An object of the invention is therefore to provide an improved component of a rolling bearing whose surface structure has good lubricant retention.

The object is solved by the subject matter of claim 1. Advantageous embodiments are described in the subclaims.

• - Wenigstens ein Oberflächenbereich des Bauelements ist mit einer Oberflächenstruktur ausgebildet,
• - die Oberflächenstruktur ist regelmäßig und durch eine lückenlose Belegung des Oberflächenbereichs mit wenigen Flächengrundelementen, die einem Quadrat, einer Raute und/oder einer Wabe ähnlich sind, gekennzeichnet und
• - in ihren Umfangsbereichen sind die Flächengrundelemente gegenüber ihren Mittenbereichen erhöht ausgebildet.

According to claim 1, a component of a rolling bearing includes the following features:

• - At least one surface area of the component is formed with a surface structure,
• - the surface structure is regular and characterised by a continuous covering of the surface area with a few basic surface elements that are similar to a square, a rhombus and/or a honeycomb, and
• - in their peripheral areas, the basic surface elements are raised compared to their central areas.

Because the peripheral areas of the surface basic elements, which are placed one next to the other without gaps, are raised in a plateau-like manner compared to the central areas of the surface basic elements, a comparatively large amount of lubricant can be held in the recessed central area, similar to a basin, compared to the conventional design. The surface structure based on the few or a single surface basic element can be produced particularly time-effectively, simply and therefore cost-effectively using a rotary milling process. Rotary milling generally consists of a combination of a rotating workpiece with a rotating milling tool. The tool can perform a feed movement. In rotary milling, methods for controlled cut overlap are also known, whereby the tool is moved again over the surface that has already been machined after one revolution of the workpiece, so that the incisions of the cutting edge are no longer made in exactly the same place as one workpiece revolution before, so that the surface quality is improved by removing the remaining roughness peaks. In addition, it is particularly advantageous that turn-milling can be carried out without the use of a particularly liquid cooling lubricant, which also eliminates the need for time-consuming separation of chips from the cooling lubricant.

In an advantageous embodiment, the surface structure can be formed in at least one area of a component that is intended for rolling or mixed rolling-sliding contact with another component. The said retention of lubricant significantly increases the service life of the two contact partners. For example, in the case of rolling contact, the mechanism can be imagined in such a way that, particularly when rolling over a rolling surface with said surface structure, the rolling element elastically presses in the raised areas of the structure and thus lubricant is, so to speak, rolled out of the center areas of the basic surface elements to the rolling element from the recessed center areas.

In another advantageous embodiment, said surface structure can also be provided in an area of a component of the rolling bearing that is intended to be firmly attached to another component. This particularly applies to areas and/or areas of use in which potentially undesirable fretting corrosion is to be expected as a result of repeated micro-movements between the two components. The preceding lubricant retention advantageously counteracts fretting corrosion.

• 1 einen Längsschnitt durch einen oberen Bereich eines Kegelrollenlagers,
• 2 eine Oberflächenstruktur der Wälzkontaktflächen des Kegelrollenlagers der 1, und
• 3 eine alternative Oberflächenstruktur der Wälzkontaktfläche.

Further advantages, features and details of the invention emerge from the embodiments of the invention described below with reference to the figures. In the figures:

• 1 a longitudinal section through an upper area of a tapered roller bearing,
• 2 a surface structure of the rolling contact surfaces of the tapered roller bearing of the 1 , and
• 3 an alternative surface structure of the rolling contact surface.

The 1 shows a longitudinal section through a single-row tapered roller bearing as an embodiment of the invention. The tapered roller bearing comprises an inner ring 30 and an outer ring 20, the two rings 20 and 30 each being designed with a rolling contact surface 22 and 32 on which the shells of the tapered rollers 10 are provided for rolling. For the sake of simplicity, other components that may be present, such as a cage for the tapered rollers 10 and/or seals, are not shown.

After the two rings 20 and 30 have been produced in the usual way, instead of a final grinding and/or long-term honing operation for the rolling contact surfaces 22 and 32, the rolling contact surfaces 22 and 32 are turn-milled. The rings 20 and 30 are, for example, conventionally made from a rolling bearing steel and hardened prior to turn-milling. During turn-milling, the rings 20 and 30 are rotated and machined with a milling tool that is also rotating. The said turn-milling can be carried out much more quickly than conventional final machining by grinding and/or long-term honing and, with particular advantage, no cooling or lubrication is required during turn-milling.

The rotary milling is set in such a way that the rolling contact surfaces 22 and 32 are provided with a surface structure according to the 2 are formed, whereby the surface structure in the 2 is shown in detail.

The surface structure is characterized by a gapless coverage with a single basic surface element, in this case a honeycomb. In other embodiments, other basic surface elements that allow a gapless surface coverage with one and the same basic surface element, for example a diamond or a square, can of course also be used.

In the 2 Only the peripheral areas of the basic surface elements are shown, whereby these peripheral areas are raised by a few to a few and a maximum of a few 10 µm in a plateau-like manner compared to the respective central area of the basic surface elements. The diameter of the basic surface element is a few millimeters. If necessary, the turn-milled surfaces can be honed for a short time after turn-milling, for example in order to remove peaks in the plateau-like raised areas in order to ensure a sufficient or desired load-bearing proportion of the rolling contact surfaces 22 and 32 for the rolling bearing. The specified height difference then applies after honing has been completed.

If the tapered roller bearing is appropriately lubricated with grease or oil, the advantages described at the beginning to solve the problem are achieved. What has been described above also applies, of course, to other rolling bearings, for example a double-row tapered roller bearing, but also to other types of bearings, such as cylindrical roller bearings, needle bearings, spherical roller bearings and ball bearings, as well as universal joints. The rolling element, particularly in the form of a roller, can also be machined in this way, which can be particularly advantageous for large-diameter bearings, since the rings can only be machined in this way with a certain amount of effort.

In other embodiments, such a surface structure can also be formed on the rim of the inner ring of the tapered roller bearing, for example, whereby a mixed rolling-sliding contact occurs between an inner side of the rim and the tapered roller faces. Said surface structure can also be used to advantage in the case of pure sliding contact, as typically occurs on a cage of a rolling bearing.

The 3 shows as a further embodiment of the invention in the form of a detail an alternative design of the rolling contact surfaces 22 and 32, which are also produced by rotary milling. The surface structure of the 3 different from that of 2 not just one, but several different honeycomb-like surface basic elements. The surface structure can be formed intentionally by selecting a rotary milling head, rotation speeds of rotary milling cutter and/or workpiece, feed speeds, and the like. In the 3 There is a type of one of the basic surface elements formed as a vertically stretched honeycomb, which is arranged along a screw-like line, for which purpose this type is shown with dots for better recognition. The six honeycombs arranged around a vertically stretched honeycomb result, so to speak, from a slight distortion of a regular honeycomb, so that in the embodiment of the 3 With the one stretched honeycomb and the six slightly distorted honeycombs, seven basic surface elements are obtained.

In one embodiment, the vertically stretched honeycomb can also be designed somewhat deeper than the others, for which purpose, for example, a rotary milling head is designed in such a way that it has several rotary milling cutting edges distributed around the circumference, one of which is designed to protrude somewhat further, which then creates the deeper honeycomb. The The remaining honeycombs can also be designed to be so slightly recessed that after a subsequent short-term honing, in fact almost only the vertically stretched honeycombs remain as lubricant-holding recesses, whereby a desired, in particular high, load-bearing proportion can be set.

For example, is the 1 If the rolling bearings shown are intended for installation in an installation environment in which potentially undesirable fretting corrosion is to be expected, one or both end faces 26, 27, 36 and 37 of the inner and/or outer ring 20 and 30, the inner shell 34 of the inner ring 30 and/or the outer shell 24 of the outer ring can of course also be designed with the said surface structure, wherein, for example, a lubricant must be applied to the surface areas with the surface structure during installation. The same naturally also applies to other components of rolling bearings. In the case of fretting corrosion, it is of course also possible to additionally or alternatively design the corresponding counterpart of the component of the rolling bearing with the said surface structure.

The above description is not limited to bearings for rotating or pivoting components, but can also be used for linear bearings.

Claims (17)

Component of a rolling bearing, comprising the following features: - At least one surface area of the component is formed with a surface structure, - the surface structure is regular and characterized by a gapless coverage of the surface area with a few basic surface elements that are similar to a square, a rhombus and/or a honeycomb, and - in their peripheral areas, the basic surface elements are raised compared to their central areas. component according to claim 1 , whereby the height difference between the peripheral region and the central region is a few to several µm, a maximum of a few 10 µm, in particular between 10 and 60 µm. Component according to one of the Claims 1 or 2 , wherein a diameter or an edge length of the basic surface element is in the range of a few tenths of a millimeter to a few millimeters, in particular in the range of 0.1 to 7 mm. Component according to one of the Claims 1 until 3 , wherein at least one specific surface element is arranged along a helical line. Component according to one of the Claims 1 until 4 , where the surface area is regularly occupied by a single surface primitive. Component according to one of the Claims 1 until 5 , whereby the surface structure is created by rotary milling. component according to claim 6 , whereby the turning milling on the hardened component is carried out free of any subsequent material-removing machining. Component according to one of the Claims 6 or 7 , whereby the turn-milled surface is briefly honed following the turn-milling process. Component according to one of the Claims 1 until 8 , wherein the surface region is a surface of the component which is intended for rolling or mixed rolling-sliding contact with another component. component according to claim 9 , wherein the surface area is a surface of a raceway element of the rolling bearing on which rolling elements are provided for rolling, or of a rolling element. component according to claim 10 , wherein the rolling bearing is designed as a roller bearing, in particular a tapered or cylindrical roller bearing. Component according to one of the Claims 1 until 11 , wherein the surface area is a surface of the component with which the component is intended to rest firmly or fasten to another component. component according to claim 12 , where the surface belongs to an inner or outer shell or an end face of a ring-like component. Component according to one of the Claims 1 until 13 , wherein the surface structure is intended for lubrication with a lubricant. component according to claim 14 , wherein the lubricant comprises an oil and/or a grease. Component according to one of the Claims 14 and 15 , which is a lifetime lubrication that does not require relubrication. Component according to one of the Claims 1 until 16 , where the number of the few surface primitives is less than 25, in particular less than or equal to 10.

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