DE102013012859A1 - Sliding element for variable valve control unit for actuating gas exchange valve in camshaft for reciprocating piston internal combustion engine, has internal toothing formed with receiving opening and rotatably connected with shaft - Google Patents

Abstract

The element (16) has an internal toothing (20) formed with a receiving opening (18) through which the sliding element on a shaft (12) is slidably positionable in an axial direction of the shaft. The internal toothing is rotatably connected with the shaft. An outer circumference side is provided with two mutually different cam tracks (28) for lifting a valve in an axial direction. The cam tracks locally form a recess that is provided as lubricant retaining volume with a surface structuring. The material of a cam track is removed by a pulsed laser. An independent claim is also included for a method for producing a sliding element.

Description

From the general state of the art and in particular from the mass production of motor vehicles with reciprocating internal combustion engines, so-called variable valve control devices are known, which are also commonly referred to as variable valve timing systems. Such a variable valve control device is used to actuate at least one corresponding gas exchange valve of the reciprocating internal combustion engine with at least two mutually different strokes. In other words, the valve control system can be operated in a first operating state in which a first valve lift of the gas exchange valve is effected by means of the valve control device. Furthermore, the valve control device can be operated in at least one second operating state, in which a second valve lift of the gas exchange valve is effected by the valve control device. In this case, the second valve lift is lower or greater than the first valve lift. Due to this variability of the valve lift, the valve lift can be adapted to different operating states of the reciprocating internal combustion engine, so that a particularly efficient operation can be realized.

In order to be able to effect the at least two mutually different valve lifts, the valve control device comprises at least one sliding piece associated with the gas exchange valve. The sliding piece has at least one receiving opening, which on the inner peripheral side with a toothing, d. H. is provided with an internal toothing. About this receiving opening, the sliding piece can be arranged or stored on a corresponding shaft or a shaft body.

The shaft has an external toothing corresponding to the internal toothing. The sliding piece is in its state arranged on the shaft, although rotatably connected to the shaft, but in the axial direction of the shaft, d. H. be moved in the longitudinal direction thereof relative to the shaft. Thereby, it is possible that the shaft, which is rotatable about an axis of rotation, entrains the sliding piece when the shaft is rotated about its axis of rotation. This also allows the sliding piece to rotate about the axis of rotation. In other words, the sliding piece rotates with the shaft. However, the sliding piece can be displaced relative to the shaft in translation in the axial direction of the shaft.

To effect the at least two mutually different valve lifts, the sliding piece has at least two outer circumferential side, mutually different cam tracks. The cam tracks are juxtaposed in the axial direction of the slider which coincides with the axial direction of the shaft. The gas exchange valve can be actuated at least indirectly by the respective cam tracks. A first of the cam tracks causes a first of the valve lifts, the second cam track causing the second valve lift.

By moving the sliding piece relative to the shaft and relative to the gas exchange valve, the respective cam tracks can be brought into an at least indirect interaction with the gas exchange valve, thereby making it possible to set an appropriate adjustment of the respective valve strokes.

It can be provided that the sliding piece interacts directly with the gas exchange valve, or this contacted. Alternatively, a switching element may be provided, which transmits from the sliding piece on its respective cam track outgoing actuating forces for actuating the gas exchange valve to the gas exchange valve. In other words, the gas exchange valve can be actuated by switching element of the sliding piece. Such a switching element is, for example, a drag lever or a plunger.

An element which can be actuated directly via the respective cam track of the sliding piece, d. H. which interacts directly with the sliding piece via the respective cam track, is also referred to as a cam follower. A cam follower is therefore generally an element which is in direct contact via the cam track with the sliding piece or with a cam track of the cam having the sliding piece or is actuated directly by the cam. Such a cam follower is, for example, the drag lever. However, the cam follower may also be the gas exchange valve itself, a plunger or other element which is actuated via the cam and its cam track.

Depending on the configuration of the cam follower and / or the cam track, there may be a sliding and / or rolling tap. This means that it can come between the sliding piece and the corresponding cam follower to a sliding and / or a rolling contact.

The sliding piece and the corresponding cam follower form a pairing, in particular a sliding and / or rolling pairing, which is usually very problematic from a wear point or tribological point of view, since depending on the direction of rotation of the shaft and thus of the sliding piece and depending on the side of the one Lubricant is introduced between the cam track or the sliding piece and the cam follower, a lubricant film may not be sufficient to keep wear of the sliding piece and the cam follower sufficiently low. The lubricant is, for example, lubricating oil, which serves for cooling and / or in particular for lubricating said pairing. The reason for the wear, for example, on the cam track and thus on a surface of the sliding piece are therefore unfavorable lubrication conditions.

The DE 196 14 328 A1 discloses a method for coating and / or machining pretreated workpiece surfaces. It is envisaged that the workpiece surfaces to prepare the coating and / or a fine machining, in particular honing by means of honing stones, are structured in a regular pattern by means of laser beams.

Object of the present invention is to further develop a sliding piece and a method for producing such a sliding piece such that the wear of the sliding piece and the corresponding cam follower can be kept particularly low.

This object is achieved by a sliding piece having the features of patent claim 1 and by a method having the features of patent claim 5. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the remaining claims.

In order to provide a sliding piece for a variable valve control device, the operational wear can be kept particularly low, it is inventively provided that at least one of the cam tracks of the sliding piece is locally provided with formation of depressions as lubricant retention volumes with a surface structuring. The local recesses constitute respective lubricant retention volumes, with a lubricant retention volume of the sliding piece being created by these individual lubricant volumes, in which lubricant, for example lubricating oil, which is introduced, for example, between the sliding piece and the corresponding cam follower, can be retained or collected at least temporarily.

In this way, an improved supply of lubricant tribological partner in the form of the sliding piece and the corresponding cam follower in a sliding and / or rolling tap can be created so that the wear of the sliding piece and the cam follower can be kept particularly low during operation. The sliding piece and a camshaft comprising the sliding piece and the shaft thus have an increased wear resistance compared with the prior art due to the surface structuring of the at least one cam track.

The surface structuring is provided locally or locally. This means that the at least one cam track has at least one first subregion in which the surface structuring is provided. Furthermore, the at least one cam track has at least one second partial area adjoining the first partial area, in which the at least one cam track is free of surface structuring or is not provided with or without surface structuring. As a result, the time and cost of producing the sliding piece can be kept particularly low.

The invention is based in particular on the recognition that the load acting on the sliding piece on its cam track is not the same everywhere, but may be locally different. Due to the only local provision of the surface structuring, the sliding piece can be specifically provided on its cam track in the areas with the surface structuring, in which it also comes to high loads. Thus, the lubrication conditions can be improved specifically in these areas.

Preferably, it is provided that the at least one cam track is locally provided with the formation of recesses as lubricant retention volumes and while avoiding at least adverse structural changes of a base material of the sliding piece with the surface structuring. Particularly preferably structural changes are avoided at all.

In the at least one first subarea, essentially only depressions without disadvantageous microstructural changes are produced by the structuring. In other words, the at least one cam track in the at least one first subregion is provided with the surface structuring in such a way that no or at least no disadvantageous microstructural changes occur on the base material.

Preferably, the at least one cam track is only there, that is, provided only in such a sub-area or only in such sub-areas with a surface structuring, in which a correspondingly high resistance to wear is required. This means that the or a surface structuring of the at least one Cam track is introduced precisely at the points at which a relatively high wear is to be expected during operation of the camshaft. The positioning of the surface structuring is thus adapted to during operation on the sliding piece, in particular on the at least one cam track, acting loads, so that a targeted and needs-based and at the same time cost-effective design of the sliding piece and the camshaft can be implemented in total.

Since not the entire cam track but only at least a portion is structured, the cycle time for producing the sliding piece can be kept low. Further, since a structural change of the base material is prevented during the production of the surface structuring, after the surface structuring has been produced, a surface treatment on the finished component in the form of the sliding piece can be completely eliminated or carried out in a simple manner. The depressions of the surface structuring can be designed punctiform or punctiform.

Furthermore, it can be provided that the recesses are integrally formed, for example in the form of grooves. In this case, for example, the recesses have a substantially elongated shape and may be straight or arcuate in this case.

The invention also includes a method for producing a sliding piece, wherein it is provided according to the invention for realizing a particularly high wear resistance that the at least one cam track locally with formation of depressions as lubricant retention volumes and in particular while avoiding structural changes of a base material of the sliding piece provided with a surface structuring becomes. Advantageous embodiments of the sliding piece according to the invention are to be regarded as advantageous embodiments of the method according to the invention and vice versa.

The introduction of the depressions in the at least one cam track, that is, the production of the surface structuring takes place for example via material removal by means of laser radiation, in particular by means of pulsed laser radiation. For this purpose, in particular a short-pulse laser can be used. For generating the laser radiation, a solid-state laser, a gas laser or a diode laser can also be used.

In an advantageous embodiment of the invention, a picosecond laser is used to generate the laser radiation. Due to the method, such a picosecond laser can essentially only produce the depressions of the at least one cam track, whereby unwanted and disturbing material jettings can be avoided. In addition, structural changes or undesired and disadvantageous microstructural changes directly on the raceway surface can be avoided.

For generating the laser radiation, a femtosecond laser may be further used. Even by means of such a femtosecond laser, it is possible to produce substantially only the depressions and no disturbing material jams and to avoid structural changes directly on the raceway surface.

At least one nanosecond or one millisecond laser can also be used to generate the laser radiation. Due to the process, such lasers produce the recesses with material throws. By appropriately setting laser parameters, these lasers can be adjusted such that a microstructure change occurs only on very thin surface layers of, for example, less than 0.1 mm, which do not adversely affect the sliding piece.

In a further advantageous embodiment of the invention, the surface structuring of the at least one cam track is produced only in a region in which there is a tribological contact of the cam with the cam follower during operation of the camshaft.

Alternatively or additionally, it is advantageously provided that the at least one cam track is structured only in zones of increased wear. Such a zone extends in particular in the circumferential direction of the at least one cam track or of the sliding piece, starting from a cam tip of the at least one cam track and with respect to an axis of rotation about which the shaft and with it the sliding piece are rotatable, at most 90 ° in a first direction and / or over at most 90 ° in a second direction opposite to the first direction. In other words, the zone in which the surface structuring is provided extends up to + -90 ° to the cam tip.

It has proven to be particularly advantageous if the surface structuring comprises at least two partial areas in which the surface structuring is designed differently. The sub-area can thereby directly, ie without distance to each other, connect to each other or be spaced apart. Preferably, it is provided that the expression, that is, for example, the depth of the recesses, and / or the density, that is, how close the recesses are arranged together or how many recesses are provided per given area, depending on the local wear of the at least one cam track is formed. In this way, a targeted and needs-based production of the sliding piece can be realized.

A further embodiment is characterized in that the surface structure is produced in time after a grinding, in particular a finish grinding, and / or after a finishing of the cam, in particular the camshaft.

In a further advantageous embodiment of the invention, it is provided that at least one burr and / or at least one material charge produced by the production of the surface structuring is removed from the sliding piece, in particular removed by machining, after the surface structure has been produced. As a result, unwanted roughness and peaks of at least one cam track can be realized. At the same time, the depressions represent lubricant retention volumes in which lubricants, such as lubricating oil, can at least temporarily be retained.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings; these show in:

1 a schematic longitudinal sectional view of a arranged on a corresponding shaft sliding piece according to a first embodiment of a variable valve timing device for actuating at least one gas exchange valve with at least two mutually different valve strokes, wherein the sliding piece at least two in the axial direction of the sliding piece juxtaposed cam tracks for effecting different valve strokes of the gas exchange valve and wherein at least one of the cam tracks is provided with a surface structuring locally forming depressions as lubricant retention volumes;

2 a schematic side view of the sliding piece according to a second embodiment;

3 a schematic front view of one of the cams;

4 a schematic side view of the cam;

5a -G each show a schematic and developed plan view of a respective embodiment of the cam track of the cam.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

1 discloses a camshaft 10 with a shaft in the form of a wave body 12 , which has an external toothing 14 having. The camshaft 10 is assigned to a variable valve control device, by means of which at least one gas exchange valve of a reciprocating internal combustion engine can be operated with at least two mutually different valve strokes. The variable valve control device also includes a sliding piece 16 which has a receiving opening in the form of a passage opening 18 having. The passage opening 18 is with one with the external teeth 14 corresponding internal toothing 20 Mistake.

How out 1 is recognizable, is the sliding piece 16 over the passage opening 18 on the shaft body 12 in the axial direction of the shaft main body 12 slidably arranged relative to the shaft main body and rotationally fixed to the shaft main body 12 connectable. In other words, in the context of the production of the variable valve control device is the sliding piece 16 on the shaft body 12 arranged by the shaft body 12 through the passage opening 18 is inserted through it. In this case, the external teeth 14 in cooperation with the internal toothing 20 brought. Due to the external toothing 14 and the internal teeth 20 is the sliding piece 16 rotatably with the shaft body 12 connected.

The camshaft 10 For example, is mounted rotatably on a cylinder head of the reciprocating internal combustion engine about an axis of rotation relative to the cylinder head. Due to the interaction of the internal teeth 20 with the external teeth 14 becomes the sliding piece 16 from the shaft body 12 taken along, when the shaft main body is rotated about the axis of rotation.

The external toothing 14 and the internal teeth 20 However, let it be that the sliding piece 16 in the longitudinal extension direction of the shaft main body 12 and thus in the axial direction of the shaft main body 12 relative to the shaft body 12 can be moved. As will be explained in the following, can be adjusted by this displacement, whether the gas exchange valve is actuated with a first valve lift or with the opposite lower, second valve lift.

The sliding piece 16 is formed in one or more pieces and has a shaft portion 22 in order to also high torques between the shaft main body 12 and the sliding piece 16 to be able to transfer. In addition, the sliding piece points 16 a first cam 24 and a second cam 26 on. The cams 24 . 26 are in the axial direction of the sliding piece 16 arranged side by side or sequentially, wherein the axial direction of the sliding piece 16 with the axial direction of the shaft main body 12 falls together. The cams 24 . 26 each have an outer peripheral side cam track 28 on. Accordingly, the cam tracks 28 in the axial direction of the sliding piece 16 arranged side by side. How out 1 can be seen, are the cam tracks 28 formed differently from each other. Through the cam tracks 28 Thus, two geometrically different cam functional surfaces are created, via which the gas exchange valve can be actuated in each case. Is the gas exchange valve on the cam track 28 of the first cam 24 actuated, it executes the first valve lift. However, the gas exchange valve on the cam track 28 of the second cam 26 operated, the gas exchange valve performs the second valve, which is lower compared to the first valve.

To the gas exchange valve by means of the first cam 24 or its cam track 28 to operate, there is the sliding piece 16 for example in an in 1 shown, first position relative to the shaft body 12 , However, the gas exchange valve by means of the second cam 26 via its cam track 28 be pressed, then the sliding piece 16 in the axial direction to the shaft main body 12 shifted relative to this from the first position to a second position. In this second position, the sliding piece acts 16 over the second cam 26 and its cam track 28 at least indirectly with the gas exchange valve together. About the first cam 24 and its cam track 28 the sliding piece acts 16 at least indirectly with the gas exchange valve in the first position together.

It can be provided that the sliding piece 16 interacts directly with the gas exchange valve, wherein the respective cam track 28 the gas exchange valve touched directly. Alternatively it is possible that the sliding piece 16 via a switching element, such as a drag lever or a plunger, cooperates with the gas exchange valve. An element, which directly with the respective cam track 28 cooperates or operated directly from this, is commonly referred to as a cam follower. With such a cam follower, it can therefore be a tappet, a drag lever or the gas exchange valve itself or else another element. The cam follower is located at one revolution of the camshaft 10 at least in part, in direct contact with one of the cam tracks 28 ,

2 shows the sliding piece 16 according to a second embodiment. How out 2 can be seen has the sliding piece 16 a first cam element 30 with cams 24 . 26 and a second cam element 32 with cams 24 . 26 on. The cam element 30 is assigned to a first gas exchange valve, while the cam element 32 associated with a second gas exchange valve. In other words, the first gas exchange valve is partially through the cam 24 or the cam 26 of the first cam element 30 actuated, wherein the second gas exchange valve optionally via the cam 24 or the cam 26 of the second cam element 32 is pressed. Because the cam elements 30 . 32 over the shaft area 22 connected to each other, the cam elements 30 . 32 moved together, so that the respective valve lift of the first gas exchange valve and the second gas exchange valve can be switched simultaneously. The cam elements 30 . 32 and the shaft area 22 , are preferably formed integrally with each other.

Order now the wear of the sliding piece 16 and the associated cam follower to keep particularly low and a particularly high resistance to wear of the sliding piece 16 To provide, it is provided that at least one of the cam tracks 28 locally under formation of depressions 34 ( 5a -G) as lubricant retention volumes and while avoiding adverse structural changes of a base material of the sliding piece 16 with a surface structuring 36 ( 3 and 4 ) is provided. The sliding piece 16 is made of the base material. It can only be one of the cam tracks 28 or both cam tracks 28 with a respective surface structuring 36 be provided.

How very good 3 and 4 it can be seen, is not the entire cam track 28 with the surface structuring 36 Mistake. Rather, the surface structuring 36 only in at least one subarea 48 the cam track 28 arranged. In this case, the cam track 28 at least one to the subarea 48 subsequent, further subarea 46 on, in which the cam track 28 is free from surface structuring.

In 3 is the axis of rotation around which the camshaft 10 and thus the respective cam 24 . 26 rotate during operation, denoted by D. The cams 24 . 26 each have a cam tip 42 on. How out 3 can be seen, the surface structuring extends 36 that is the subarea 48 starting from the cam tip 42 in the circumferential direction of the respective cam 24 . 26 and based on the axis of rotation D over up to about 90 ° in a first direction or with respect to the image plane of 3 to the left and / or up to about 90 ° in a direction opposite to the first direction, second direction or with respect to the image plane of 3 to the right. This is also very good 4 recognizable.

3 and 4 thus show one of the cams 24 . 26 that is not structured along the entire career path. Rather, the surface structuring is limited 36 on at least one tribologically highly stressed zone in the form of the subarea 48 , The surface structuring 36 may alternatively or additionally be limited to individual separate sections that are in a range of + -90 ° about the cam tip 42 are arranged.

According to 3 and 4 this is the subarea 48 around a structured area. The further subarea 46 is ground and / or finished and not provided with a surface structuring.

Preferably, it is provided that the surface structuring 36 is produced by laser radiation. Thus, the surface structuring 36 designed as laser structuring. The further subarea 46 is free from laser structuring.

Out 4 it can be seen that the subarea 48 relative to the axial direction of the cam 24 . 26 a central region of the cam 24 . 26 is. The cam 24 . 26 also has border areas 44 on, which in the axial direction on both sides of the sub-area 48 connect. In other words, the border areas 44 in the axial direction next to the subregion 48 arranged. Here are the border areas 44 not with the surface structuring 36 or provided with a surface structuring, in particular in the form of a laser structuring. The axial extent of the respective edge region 44 is preferably in a range of 0.1 mm to 1 mm inclusive. In the border areas 44 can be dispensed with a surface structuring, since there is no tribological contact with the counter body, that is, the cam follower. The cam track 28 is thus only locally related to the surface structuring both in terms of its extent and in terms of its width 36 Mistake.

5a -G show different embodiments of surface structuring 36 , These are exemplary embodiments, which can also be combined with each other.

How out 5a recognizable form the depressions 34 the surface structuring 36 a substantially regular grid of individual points. These are ideally essentially round. The individual points can also be oval or have a polygonal geometry.

In the surface structuring 36 according to 5b are some of the single points about oblong depressions 38 interconnected with the elongated depressions 38 just train and channels for the lubricant.

According to 5c is a so-called center gutter 40 the cam track 28 from the surface structuring 36 omitted, because there are no or only low loads.

Out 5d it can be seen that the individual wells 34 present in the form of points with respect to each other may have different sizes. For example, the punctiform depressions 34 have different diameters. This can also be done according to 5b described channels are transmitted, which may have different lengths from each other.

In the surface structuring 36 according to 5e is the occupancy of the wells 34 not uniformly dense over the surface to be structured but adapted to respective requirements and in particular loads. In the surface structuring 36 according to 5 are the depressions 34 , which are punctiform in this case, stochastically distributed.

According to 5g are the depressions 34 as oblong and present straight depressions 38 formed, which form channels and intersect, that is cross over each other. This means that the channels partially overlap. Such overlap allows lubricant to flow, for example, from one of the channels to the other. But these channels can also have a curved shape.

Through the depressions 34 Thus, lubricant reservoirs are created in which lubricants such as lubricating oil, which during operation between the cam 24 . 26 and the corresponding cam follower is retained. As a result, particularly advantageous lubrication conditions can be created, so that the wear can be kept low. This results in a particularly high wear resistance and a high component life. As a result, unwanted and wear-related noise over a particularly long life of the reciprocating internal combustion engine can be avoided.

It can be provided that only the cam track 28 of the first cam 24 or only the cam track 28 of the second cam 26 locally with the surface structuring 36 is provided. Furthermore, it can be provided that both cam tracks 28 with the surface structuring 36 are provided locally. Because by the first cam 24 opposite the second cam 26 a larger stroke of the valve is effected, is the first cam 24 also referred to as high-lift cam, while the second cam 26 is referred to as Niederhubnocken.

Alternatively or additionally, the sliding piece 16 or may also have an outer peripheral side surface 33 of the shaft area 22 be at least partially provided with a corresponding surface structuring. As part of the production of surface structuring 36 It is also possible to deliberately provide feed tracks or feed channels via which floating or lubricating oil can be guided in a targeted manner into predetermined areas.

In principle, it is also conceivable that the above-mentioned surface structuring 36 according to 5a -G are connected to a broken or continuous channel, this channel also outside the area of at most 90 degrees in the one direction around the cam tip 16 and / or at most 90 degrees in the other direction about the cam tip 16 begins and / or ends. Such a channel serves in this case as a kind of oil supply channel.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19614328 A1 [0010]

Claims (10)

Sliding piece ( 16 ) for a variable valve control device for actuating at least one gas exchange valve with at least two mutually different valve lifts, with at least one with an internal toothing ( 20 ) receiving opening ( 18 ) over which the sliding piece ( 16 ) on a wave ( 12 ) in the axial direction of the shaft ( 12 ) relative to this slidably arranged and rotationally fixed to the shaft ( 12 ) is connectable, and with at least two outer peripheral side, mutually different and axially juxtaposed cam tracks ( 28 ) for effecting the respective valve strokes, characterized in that at least one of the cam tracks ( 28 ) locally with formation of depressions ( 34 ) as lubricant retention volumes with a surface structuring ( 36 ) is provided. Sliding piece ( 16 ) according to claim 1, characterized in that the at least one cam track ( 28 ) by material removal by means of a laser, in particular by means of a pulsed laser, with the surface structuring ( 36 ) is provided. Sliding piece ( 16 ) according to one of claims 1 or 2, characterized in that the surface structuring ( 36 ) only in at least one subarea ( 48 ) the at least one cam track ( 28 ), the subregion ( 48 ) in the circumferential direction of the sliding piece ( 16 ) starting from a cam tip ( 42 ) the at least one cam track ( 28 ) extends at most 90 degrees in a first direction and / or at most 90 degrees in a second direction opposite to the first direction. Camshaft ( 10 ), in particular for a reciprocating internal combustion engine, with at least one sliding piece ( 16 ) according to any one of the preceding claims. Method for producing a sliding piece ( 16 ) for a variable valve control device for actuating at least one gas exchange valve with at least two mutually different valve strokes, wherein the sliding piece ( 16 ) at least one with an internal toothing ( 20 ) receiving opening ( 18 ), over which the sliding piece ( 16 ) on a wave ( 12 ) in the axial direction of the shaft ( 12 ) relative to this slidably arranged and rotationally fixed to the shaft ( 12 ) is connectable, and wherein the sliding piece ( 16 ) at least two outer peripheral side, mutually different and axially juxtaposed cam tracks ( 28 ) are provided for effecting the respective valve strokes, characterized in that at least one of the cam tracks ( 28 ) locally with formation of depressions ( 34 ) as lubricant retention volumes with a surface structuring ( 36 ). Method according to claim 5, characterized in that adjacent areas of the sliding piece ( 16 ) by introducing the surface structuring ( 36 ) are not changed. Method according to claim 5 or 6, characterized in that the at least one cam track ( 28 ) by means of a laser, in particular a pulsed laser, with the surface structuring ( 36 ). A method according to claim 7, characterized in that a solid-state laser, a gas laser or a diode laser is used as the laser. Method according to one of claims 7 or 8, characterized in that a picosecond laser, a femtosecond laser, a nanosecond laser or a millisecond laser is used as the laser. Method according to one of Claims 5 to 9, characterized in that, after the at least one cam track has been provided ( 28 ) with the surface structuring ( 36 ) at least one caused by the accident material throw and / or burr from the sliding piece ( 16 ) Will get removed.

Images