Steel piston for an internal combustion engine

Abstract

A steel piston (10) for an internal combustion engine has a cooling channel and shaft surfaces (12, 14) with which the piston (10), in the installed state, abuts a cylinder bore or a cylinder liner on a pressure side and a counterpressure side, wherein one shaft surface (12) has a width which is 25-50% smaller than the other shaft surface (14).

Claims

1. A steel piston for an internal combustion engine, having at least one cooling channel and shaft surfaces with which the piston, in an installed state, abuts a cylinder bore or a cylinder liner on a pressure side and a counterpressure side, wherein said shaft surfaces are connected to a piston hub by connecting walls, one of said shaft surfaces has a width which is 25-50% smaller than the other of said shaft surfaces, and wherein a cooling channel outlet is disposed inward of said shaft surface and is centrally arranged between said connecting walls on the side of the narrower shaft surface.

2. The piston according to claim 1, wherein the narrower shaft surface is wider at one end directed towards a piston crown than at an end opposite to the piston crown.

3. The piston according to claim 1, wherein at least one of said connecting walls between the shaft surface and the piston hub is designed obliquely.

4. The piston according to claim 1, wherein the wider shaft surface has at least one convexity on the inside.

5. The piston according to claim 1, wherein the piston comprises at least two components joined by friction welding.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the invention is explained in more detail using an embodiment example from the drawings.

(2) The figures show as follows:

(3) FIG. 1 an underside view of the piston according to the embodiment of the invention; and

(4) FIG. 2 a side view of the piston according to the embodiment of the invention.

DETAILED DESCRIPTION

(5) As can be seen in the piston 10 of FIG. 1, a shaft surface 12, which in the example shown is provided on the counterpressure side, and a shaft surface 14 on the pressure side are connected by connecting walls 20 to a piston hub 26, which comprises the piston pin bore. The shaft surface 12 on the counterpressure side is clearly smaller, in particular narrower, as can be seen additionally in the side view of FIG. 2. However, the shaft surface 14 on the pressure side can also be made smaller if the position of the oil spray nozzle is on the counterpressure side.

(6) FIG. 1 additionally shows that a cooling channel outlet 16 is arranged essentially centrally, while the cooling channel inlet 24 is provided laterally. With regard to the pressure side, FIG. 1 shows a preferred embodiment in such a way that the inner side of the shaft wall has a convexity 22 on this side at the lower end. However, it preferably extends over the entire “height” of the shaft wall in the direction of the piston axis. In other words, the wall of the shaft is essentially thickened in the middle or bulged towards the inside. The convexity, for example, extends over about one third of the width of the shaft surface 14 and, like the two transitions to the wall thickness of the shaft surface 14, is rounded. In this respect, a concavity is created on each side of convexity 22.

(7) FIG. 2 additionally shows that the smaller shaft surface 12 is slightly wider at its end facing the piston crown 18 than at the opposite end. With the exception of the clearly chamfered lower end, however, the width measured in the circumferential direction at the upper end is a maximum of 120% of the width at the lower end. In addition, the lateral edges of at least one, preferably both shaft surfaces 12, 14 extend largely straight. Finally, in the example shown, the larger shaft surface 14 has a substantially identical width at the upper and lower ends.