Method for manufacturing a piston

Patent metadata

Field	Value
Publication number	US-10837400-B2
Application number	US-201715796723-A
Country	US
Kind code	B2
Filing date	Oct 27, 2017
Priority date	Oct 28, 2016
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A method for manufacturing a piston of an internal combustion engine from a piston upper part and a piston lower part may include producing at least the piston lower part as a forged steel part. A partial cross section of a cooling duct may be provided in the piston lower part. A closed supply inlet funnel may be forged within the piston lower part. The closed supply inlet funnel may be bored into the piston lower part from the cooling duct. A borehole may be introduced into the piston lower part obliquely to a piston axis. The piston lower part and the piston upper part may be welded to one another.

First claim

The invention claimed is:

1. A method for manufacturing a piston of an internal combustion engine from a piston upper part and a piston lower part comprising:
producing at least the piston lower part as a forged steel part provided with a partial cross section of a cooling duct, and forging a closed supply inlet funnel in the piston lower part underneath the partial cross section of the cooling duct relative to the piston upper part;
boring the closed supply inlet funnel into the piston lower part from the cooling duct towards the closed supply inlet funnel by drilling a borehole through the piston lower part obliquely to a piston axis to form a supply inlet funnel connected to the cooling duct via the borehole;
welding the piston lower part and the piston upper part to one another; and
wherein drilling the borehole through the piston lower part obliquely to the piston axis includes forming an axis of the borehole to extend into the cooling duct inclined radially inwards to the piston axis, and wherein the axis of the borehole extends into the cooling duct radially inwards of an outer welding bead at an incline of less than 15° relative to the piston axis.

2. The method according to claim 1 , wherein the piston lower part and the piston upper part are welded to one another via a friction-welding connection.

3. The method according to claim 1 , wherein the piston lower part and the piston upper part are welded to one another via laser-welding.

4. The method according to claim 1 , further comprising producing the piston upper part as a forged steel part, and forging a second partial cross section of the cooling duct in the piston upper part.

5. The method of claim 1 , wherein drilling the borehole through the piston lower part obliquely to the piston axis includes guiding a drill obliquely to the piston axis from above the partial cross section of the cooling duct into the closed supply inlet funnel to form the supply inlet funnel connected to the cooling duct via the borehole.

6. The method according to claim 1 , wherein the axis of the borehole extends into the cooling duct radially inwards of a piston ring part at an incline of less than 15° relative to the piston axis.

7. The method according to claim 1 , wherein drilling the borehole through the piston lower part obliquely to the piston axis includes introducing the borehole in a direction running from the partial cross section of the cooling duct towards an interior of the piston lower part and into the closed supply inlet funnel to form the supply inlet funnel.

8. The method according to claim 1 , wherein the axis of the borehole is inclined radially inwards by an angle of 5°<α<12.5° relative to the piston axis.

9. A piston comprising:
a forged steel piston lower part having a first partial cross section of a cooling duct disposed therein;
a piston upper part having a second partial cross section of the cooling duct disposed therein;
a supply inlet funnel provided in the piston lower part and disposed underneath the cooling duct relative to the piston upper part;
a borehole defined within the piston lower part and extending obliquely to a central piston axis, the borehole connecting the supply inlet funnel and the cooling duct;
wherein the piston upper part is welded to the piston lower part;
wherein the borehole has an axis extending into the cooling duct that is inclined radially inwards to the central piston axis; and
wherein the cooling duct includes a radially outer welding bead, and wherein the axis of the borehole extends into the cooling duct radially inwards of the welding bead at an incline of less than 15° relative to the central piston axis.

10. The piston according to claim 9 , wherein the piston lower part includes a piston shaft protruding from the piston lower part axially away from the piston upper part relative to the central piston axis, the piston shaft extending around an outer circumferential edge of the piston lower part relative to the central piston axis defining an interior of the piston lower part.

11. The piston according to claim 9 , wherein the piston upper part further includes a combustion bowl and a ring part.

12. The piston according to claim 9 , wherein the piston lower part further includes a ring part and a first portion of a combustion bowl; and
the piston upper part forms a second portion of the combustion bowl.

13. The piston according to claim 9 , wherein the axis of the borehole is inclined radially inwards by an angle α<15° to the central piston axis in a direction running from the supply inlet funnel to the cooling duct.

14. An internal combustion engine with at least one piston according to claim 9 .

15. The piston according to claim 9 , wherein the axis of the borehole is inclined radially inwards by an angle 5°<α<12.5° to the central piston axis in a direction running from the supply inlet funnel to the cooling duct.

16. The piston according to claim 9 , wherein the axis of the borehole extends into the first partial cross section radially inwards of a radially outer wall of the cooling duct.

17. A piston comprising:
a forged steel piston lower part having a first partial cross section of a cooling duct disposed therein;
a supply inlet funnel provided in the piston lower part;
a borehole defined within the piston lower part and extending obliquely to a piston axis, the borehole connecting the supply inlet funnel and the cooling duct; and
a piston upper part having a second partial cross section of the cooling duct disposed therein;
wherein the piston upper part is welded to the piston lower part;
wherein the borehole extends inclined radially inwards to the piston axis from the supply inlet funnel towards the cooling duct; and
wherein the cooling duct includes a radially outer welding bead, and wherein the borehole has an axis extending into the cooling duct radially inwards of the radially outer welding bead at an incline of less than 15° relative to the piston axis.

18. The piston according to claim 17 , wherein the axis of the borehole is inclined by an angle of 5°<α<12.5° relative to the piston axis.

Assignees

• Mahle Int Gmbh

Inventors

• Keller Klaus
• Scharp Rainer

Classifications

• B23K26/21 Primary

  by welding · CPC title

• F02F2003/0061

  by welding · CPC title

• F02F3/22

  the fluid being liquid · CPC title

• B23K20/129

  specially adapted for particular articles or work · CPC title

• B23K2101/003

  Pistons · CPC title