Method for structuring at least one sliding surface of a machine element

Abstract

A method for structuring at least one sliding surface (4) of a machine element (1), wherein the at least one sliding surface (4) is provided by a first structuring method with a first microstructure (5) for holding lubricant. To be able to now realize the best possible sliding properties for the sliding surface, during the course of a second structuring method, recesses are formed in the at least one sliding surface (4), by which a second microstructure (6) is defined with less depth in comparison with the first microstructure.

Claims

1. A method for structuring at least one sliding surface of a machine element, the method comprising providing the at least one sliding surface with a first microstructure for holding lubricant using a first structuring method, wherein the first structuring method is performed using a direct structuring method, in which individual structures isolated from each other are formed by a single laser beam, and the individual structures have a depth of 40-50 m, and forming further structures in the at least one sliding surface using a second structuring method defining a second microstructure with less depth in comparison with the first microstructure, wherein the second structuring method is performed using a laser interference structuring method with a maximum depth of 1.5 m of the further structures.

2. The method according to claim 1, wherein the further structures of the second microstructure are formed periodically one after another.

3. The method according to claim 1, wherein the further structures of the second microstructure comprise differently shaped contours in a sliding direction, wherein areas of the machine element with higher expected sliding speeds occurring along the sliding surface are realized with an increased retention of lubricant.

4. The method according to claim 1, wherein a contact surface of a cam follower of a valve train is processed as the sliding surface.

5. The method according to claim 1, wherein a running surface of a cam of a valve train is processed as the sliding surface.

6. A machine element, comprising at least one sliding surface processed according to a method according to claim 1.

7. The machine element according to claim 6, wherein the machine element is a cam follower or cam for a valve train of an internal combustion engine.

8. The method according to claim 1, wherein the individual structures are formed as diamond-shaped pockets when viewed in a direction normal to the sliding surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A preferred embodiment of the invention is explained in more detail below with reference to the accompanying drawings. Shown therein are:

(2) FIG. 1a schematic representation of a sliding contact of two machine elements, of which one has been processed corresponding to the method according to the invention; and

(3) FIG. 2a top view of the sliding surface of the machine element from FIG. 1 processed according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) FIG. 1 shows a schematic view of a sliding contact between two machine elements 1 and 2, wherein the machine element 1 is preferably a cam follower, for example, a rocker arm, while the machine element 2 is provided as a cam of a valve camshaft. For lubricating the sliding contact between the machine elements 1 and 2, a lubricant film 3 is formed between these elements, wherein the lubricant is preferably oil.

(5) A sliding surface 4 of the machine element 1 has now been processed by a method for structuring according to the invention and provides, accordingly, two microstructures 5 and 6, whose actual design is visible, in particular, from the top view of FIG. 2. As can be seen here, a first microstructure 5 is provided here as diamond-shaped pockets 7, which are used for receiving and holding the lubricant. Here, the pockets 7 of the first microstructure 5 are distributed at regular intervals over the sliding surface 4 of the machine element 1.

(6) In contrast, a second microstructure 6 with less depth than the pockets 7 of the first microstructure 5 is constructed and provided as self-contained, diamond shape-like individual structures 8. These individual structures 8 are here formed uniformly over the entire sliding surface 4 one after the other and ensure a retention of the lubricant when the machine element 2 slides on the machine element 1 due to an orientation of the individual structures 8 in the sliding direction 9. Similar to an aquaplaning effect, this arrangement allows the machine element 2 to float on top of the machine element 1, so that the two machine elements 1 and 2 are not in direct mechanical contact with each other.

(7) In the scope of the method according to the invention, first the second microstructure 6 on the sliding surface 4 of the machine element 1 is constructed by forming the individual structures 8 with the help of a laser interference structuring process. Here, the individual structures 8 are formed by the periodic interaction of several laser beams with each other, wherein a maximum depth of the individual structures 8 is 1.5 m. Then the pockets 7 of the first microstructure 5 are formed by performing, at the corresponding locations, a direct structuring method by an individual laser beam. Here, the depth of the first microstructure 5 is 40-50 m.

(8) Thus, by a corresponding method for structuring a sliding surface of a machine element, different microstructures can be formed and thus an optimal adaptation of the sliding properties of this sliding surface to the expected conditions is performed.

LIST OF REFERENCE SYMBOLS

(9) 1. Machine element 2. Machine element 3. Lubricant film 4. Sliding surface 5. Microstructure 6. Microstructure 7. Pocket 8. Individual structure 9. Sliding direction