Particular arrangement of a cooling duct connecting bore of a cooling duct

1. A method for producing a cooling duct piston for an internal combustion engine comprising the steps:

producing a piston upper part while introducing a combustion bowl, one part of a cooling space, one part of a cooling duct, and at least one transfer duct having a diameter positioned solely in the piston upper part and positioned angularly offset between a horizontal and a vertical orientation;

producing a piston lower part while introducing a second part of the cooling duct and a second part of the cooling space;

joining the piston upper and lower parts along a first seam and a second seam, the first and the second seams oriented horizontally; and

characterized in that:

the at least one transfer duct between the cooling duct and the cooling space is created by boring at the angularly offset orientation relative to the horizontal first and second seam; and

forming a planar inner surface portion of the cooling duct or the cooling space having a width at least as large as the at least one transfer duct diameter, is shaped such that, in cross-section, an inlet angle α from a longitudinal axis of the at least one transfer duct to the inner surface of the cooling duct or the cooling space, measures between 85° and 95° thereby preventing deviation of a cutting bit positioned along the longitudinal axis operable for the boring of the at least one transfer duct without using countersinking.

2. The method of claim 1 wherein the inlet angle α of the at least one transfer duct measures between 87° and 93°.

3. The method of claim 1 wherein the inlet angle α of the at least one transfer duct measures between 89° and 91°.

4. The method of claim 1 wherein the inlet angle α of the at least one transfer duct measures 90°.

5. The method of claim 1 wherein boring of the at least one transfer duct occurs while the piston upper part is separate and independent of the piston lower part.

6. A method for producing a cooling duct piston for an internal combustion engine comprising the steps:

producing a separate and independent piston upper part including a combustion bowl, a first portion of a cooling space and a first portion of a cooling duct;

defining a longitudinal axis of a transfer duct to fluidly communicate between the cooling space first portion and the cooling duct first portion, the transfer duct longitudinal axis angularly oriented between the horizontal and vertical;

forming a planar surface portion on at least one of an inner surface of the cooling space or the cooling duct intersecting the transfer duct longitudinal axis, the planar surface portion oriented at an inlet angle α between 85° and 95° from the transfer duct longitudinal axis;

boring a transfer duct through the planar surface portion along the transfer duct longitudinal axis, the bored transfer duct positioned solely and within the piston upper part and without use of a countersink in the at least one of the inner surface of the cooling space or the cooling duct;

producing a piston lower part separately and independent of the piston upper part, the piston lower part including a second portion of the cooling space and a second portion of the cooling duct; and

joining the piston upper and lower parts along a horizontally oriented seam, the transfer duct longitudinal axis oriented at an angular offset from the horizontal seam.

7. The method of 6 wherein the planer surface portion is formed on an inner surface of the cooling space and the boring of the transfer duct begins at the planar surface portion extending radially and angularly outward along the transfer duct longitudinal axis and ending at the cooling duct.

8. The method of claim 6 wherein the inlet angle α is between 87° and 93°.

9. The method of claim 6 wherein the inlet angle α measures between 89° and 91°.

10. The method of claim 6 wherein the inlet angle α is 90°.