DE102016209973A1 - Valve train for an internal combustion engine - Google Patents

Abstract

The invention relates to a valve drive (1) for an internal combustion engine, comprising a cup tappet (2) which has a cup casing surface (3) and a cup end surface (4), the cup tappet (2) being received at least partially in a cylinder head (5) and axially wherein the cup tappet (2) is further axially actuated by a cam (6), and wherein the cup lateral surface (3) and / or the cup end surface (4) have a laser structure (10) for friction reduction.

Description

The invention relates to a valve train for an internal combustion engine comprising a bucket tappet, which is at least partially received in a cylinder head and axially guided.

From the DE 102 14 208 419 A1 a method for structuring at least one sliding surface of a machine element emerges. The at least one sliding surface is provided by means of a first patterning process with a first microstructure for receiving lubricant. In the course of a second patterning process, depressions are introduced into the at least one sliding surface, by means of which a second microstructure is defined with a lesser depth compared to the first microstructure.

The object of the present invention is to further develop a valve train for an internal combustion engine.

The valve train according to the invention for an internal combustion engine comprises a bucket tappet, which has a cup shell surface and a cup face, wherein the tappet is at least partially received in a cylinder head and axially guided, wherein the tappet is further axially actuated by a cam, and wherein the cup shell surface and / or the cup face for friction reduction have a laser structuring. The tappet is actuated axially by a rotation of the cam and forms a linear guide of the valve in the cylinder head. A rotational movement of the cam is thereby converted into an axial movement of the tappet. Through its own rotation, the cam slides with its sliding surface in a sliding movement over the cup face. Continuous component contact between the cam and bucket tappet is generated by means of a spring force of a valve spring. By structuring by means of a laser, the friction on the cup lateral surface and / or the cup face is reduced by improved lubrication conditions. In other words, the lubricating conditions in the contact area between the tappet and the cylinder head or the cam are thereby improved by an increased oil retention capacity and an optimized lubricating film structure of the cup casing surface and / or the cup end face. A mechanical sliding of the bucket tappet is prevented. Furthermore, the dripping of the lubricant at standstill of the internal combustion engine is largely avoided. In addition to the friction reduction, the wear in the contact point between the bucket tappet and the cam or the cylinder head is also reduced. Essentially, the cup skirt surface and / or the cup face are machined by direct-writing laser microstructuring or by direct-writing laser interference patterning.

The cup casing surface and / or the cup end surface preferably has a mechanical surface treatment. In particular, by shot peening compressive residual stresses are introduced into the surface of the cup surface and / or the cup face, whereby the fatigue strength of the component increases.

The cup casing surface and / or the cup end surface preferably has a coating. In particular, an amorphous carbon layer is applied as a coating. Furthermore, hard material layers of nitrides, carbides, oxides, and mixed forms and multilayers are applicable. In addition, however, hard chrome plating, phosphating and burnishing are also possible, which, in addition to reducing friction, also have positive effects on corrosion and fatigue strength.

The method according to the invention for the surface treatment of a tappet has the following method steps. First, a cup lateral surface and / or a cup end face are structured by means of a laser. In this case, surface material is removed by evaporation or sublimation. The resulting burrs are then removed. Optionally, the surface can be plastically deformed by mechanical surface treatments, for example shot peening. The resulting possibly resulting Aufwürfe be removed before the cup skirt surface and / or the cup face optionally and finally coated.

Further measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to the figures, in which the same or similar elements are provided with the same reference numerals. This shows

1 a schematic sectional view of a valve train according to the invention, and

2 a schematic representation of a valve train according to the invention according to 1 ,

According to 1 includes a valve train according to the invention 1 for a - not shown here - internal combustion engine a bucket tappets 2 , The tappet 2 has a cup skirt surface 3 and a cup face 4 on, with the bucket tappet 2 at least partially in a cylinder head 5 taken up and guided axially. The tappet 2 is also from a cam 6 axially actuated and thus presses on the valve 9 , By rotation of the cam 6 slides the sliding surface 7 of the cam 6 over the cup face 4 the tappet 2 , If the cam 6 in the area of the cam projection 11 along the cup face 4 slides, the valve becomes 9 axially in the direction of the valve spring 8th pressed so that the valve spring 8th is tense. Upon further rotation of the cam 6 relaxes the valve spring 8th and pushes the bucket tappet 2 turn in the direction of the cam 6 , This is between bucket tappets 4 and cams 6 realized an uninterrupted frictional contact.

To 2 has the cup skirt surface 3 the tappet 2 For friction reduction, a laser structuring 10 on. Under the laser structuring 10 is to be understood that the surface of the cup skirt surface 3 in a manufacturing process was vaporized or sublimated in places. As a result, recesses were formed that the oil retention and the film structure on the cup surface 3 optimize.

LIST OF REFERENCE NUMBERS

1

 valve train

2

 tappets

3

 Cup shell surface

4

 Cup face

5

 cylinder head

6

 cam

7

 sliding surface

8th

 valve spring

9

 Valve

10

 laser structuring

11

 cam lobe

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 10214208419 A1 [0002]

Claims (4)

Valve train ( 1 ) for an internal combustion engine, comprising a bucket tappet ( 2 ), which has a cup surface ( 3 ) and a cup face ( 4 ), wherein the tappets ( 2 ) at least partially in a cylinder head ( 5 ) is received and axially guided, wherein the tappets ( 2 ) further from a cam ( 6 ) is axially actuated, and wherein the cup surface ( 3 ) and / or the cup face ( 4 ) for friction reduction, a laser structuring ( 10 ) exhibit. Valve train ( 1 ) according to claim 1, characterized in that the cup casing surface ( 3 ) and / or the cup face ( 4 ) have a mechanical surface treatment. Valve train ( 1 ) According to claim 1, characterized in that the cup shell surface ( 3 ) and / or the cup face ( 4 ) have a coating. Process for the surface treatment of a tappet ( 2 ) according to one of claims 1 to 3, characterized in that the cup lateral surface ( 3 ) and / or the cup face ( 4 ) are structured to reduce friction with a laser.

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