Method for producing a piston for an internal combustion engine

Abstract

In a method for producing a piston (10) for an internal combustion engine, a melt treatment is performed at least in regions in particular in the region of a combustion chamber depression (14), the depth of said melt treatment being varied in the circumferential direction.

Claims

1. A method for producing a piston for an internal combustion engine, including loading a piston, finding a combustion chamber cavity, finding regions in the circumferential direction of the combustion chamber cavity, setting a less remelt depth in less loaded regions than in higher loaded regions such that the total heat input is decreased and the thermal aging of the piston as a whole is reduced by a remelt treatment, performing the remelt treatment performed by a welding process altering the parameters of at least one of current strength, voltage, distance of a welding electrode from a surface of the piston and the feed rate at least in regions of the piston, altering a depth of the remelt treatment in a circumferential direction so that the depth is greater in at least one circumferential location of the remelt treatment relative to the depth in other circumferential locations of the remelt treatment, wherein an angular relationship between a minimum thickness position of one of the at least one circumferential locations and a maximum thickness position of one of the other circumferential locations are perpendicular or acute-angular wherein the piston is made with the combustion chamber cavity and wherein the remelt treatment is performed in the region of the combustion chamber cavity.

2. The method according to claim 1, wherein the remelt treatment is performed on a rim of a combustion chamber cavity of the piston.

3. The method according to claim 2, wherein the remelt treatment is performed deeper in a region of a plane which contains a piston pin axis.

4. The method according to claim 2, including forming the piston with a cooling channel.

5. The method according to claim 2, wherein the remelt treatment is performed on a bottom of a combustion chamber cavity of the piston.

6. The method according to claim 1 wherein the step of altering the depth of the remelt treatment in the circumferential direction is further defined as altering the depth of the remelt treatment in the circumferential direction such that at least one portion of the remelt treatment has a first depth which is at least twice a second depth of another portion of the remelt treatment.

7. The method according to claim 1 wherein the step of altering the depth of the remelting treatment in the circumferential direction is further defined as continuously increasing the depth of the remelt treatment in the circumferential direction from a first location with a minimum depth to a second location with a maximum depth and continuously decreasing the depth of the remelt treatment from the second location to a third location with the minimum depth and continuously increasing the depth of the remelt treatment from the third location to a fourth location with the maximum depth and continuously decreasing the depth of the remelt treatment from the fourth location to the first location.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Hereinafter, preferred embodiment examples will be explained in more detail by means of the drawings. These show:

(2) FIG. 1 a sectional view of a piston perpendicular to the piston pin axis;

(3) FIG. 2 a sectional view of a piston through the piston pin axis; and

(4) FIG. 3 a representation of the remelt depth along the circumference.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

(5) In FIG. 1, in a section perpendicular to the piston pin axis, a piston 10 is represented, which exemplarily comprises a cooling channel 12 and a combustion chamber cavity 14. With 16, those regions are indicated in which, to increase the loading capacity, a remelt treatment with a certain depth was performed.

(6) In comparison with FIG. 2, it is shown that these regions 18 in the sectional plane, which contains the piston pin axis 20, are configured to be deeper. In other words, the remelted zone extends into deeper regions starting from the surface. By this, a particular loading capacity is achieved in the particularly loaded regions in the vicinity of the plane which contains the piston pin axis.

(7) A preferred course of the remelt depth 22 along the circumference is evident from FIG. 3. The remelt depth 22 is, preferably in the region of the plane 24 which contains the piston pin axis, at the greatest and perpendicular thereto at the least, the transitions between said extremes being configured so as to be graduated.