Method for producing a piston for an internal combustion engine and piston produced by said method

Patent metadata

Field	Value
Publication number	US-10415499-B2
Application number	US-201414778074-A
Country	US
Kind code	B2
Filing date	Mar 18, 2014
Priority date	Mar 18, 2013
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A method for producing a piston for an internal combustion engine may include the steps of: producing a first blank corresponding to a piston main body via a deformation process; producing a second blank corresponding to a piston ring part via at least one of a deformation process and a casting process; pre-machining the first blank and the second blank, and finishing a welding surface of the first blank and a welding surface of the second blank via machining; connecting the first blank and the second blank via welding the welding surface of the first blank to the welding surface of the second blank to form a piston body; and performing at least one of a secondary machining process and a finish machining process on the piston body to produce the piston.

First claim

The invention claimed is:

1. A method for producing a piston for an internal combustion engine, comprising the steps of:
a) producing a first blank corresponding to a piston main body via a deformation process, wherein producing the first blank corresponding to the piston main body includes providing a combustion depression defining a dome and a plurality of piston bosses connected to one another via a running surface, and wherein a contour of the combustion depression is fully produced;
b) producing a second blank corresponding to a piston ring part via at least one of a deformation process and a casting process, wherein producing the second blank corresponding to the piston ring part includes providing a piston crown, an annular fire land and an annular ring section arranged away from a region of combustion with respect to the fire land, and wherein the first blank and the second blank each include a welding surface;
c) pre-machining the first blank and the second blank and finish machining the welding surface of the first blank and the welding surface of the second blank to form a machined first blank and a machined second blank, wherein the machined first blank has a first cooling duct region and the machined second blank has a second cooling duct region;
d) connecting the machined first blank corresponding to the piston main body and the machined second blank corresponding to the piston ring part via welding the welding surface of the first blank to the welding surface of the second blank to form a piston body, wherein the piston body defines an annular cooling duct via the first cooling duct region and the second cooling duct region; and
e) performing at least one of a secondary machining process and a finish machining process on the piston body to produce the piston, wherein step e) includes forming boss bores into the plurality of piston bosses.

2. The method as claimed in claim 1 , wherein step c) further includes at least one of (i) forming the first cooling duct region in the first blank and forming the second cooling duct region in the second blank, and (ii) finishing the first cooling duct region and the second cooling duct region via machining.

3. The method as claimed in claim 2 , wherein step c) further includes pre-machining an outer diameter of at least one of the first blank and the second blank.

4. The method as claimed in claim 2 , wherein step c) further includes pre-machining the plurality of piston bosses on the first blank.

5. The method as claimed in claim 1 , wherein the first blank corresponding to the piston main body defines an interior space, and wherein step c) further includes finish-machining the interior space and forming an inlet opening and an outlet opening for a cooling fluid into the first cooling duct region of the first blank.

6. The method as claimed in claim 1 , wherein step c) further includes at least one of (i) pre-machining an outer diameter of at least one of the first blank corresponding to the piston main body and the second blank corresponding to the piston ring part, and (ii) pre-machining the plurality of piston bosses on the first blank corresponding to the piston main body.

7. The method as claimed in claim 1 , wherein step e) of performing the at least one of the secondary machining process and the finish machining process on the piston body includes finish machining the piston crown, and wherein the boss bores are formed into the plurality of piston bosses after the piston crown has been finish-machined.

8. The method as claimed in claim 1 , wherein producing the first blank corresponding to the piston main body includes forging the first blank via a hot working method at a temperature ranging from 1200° C. to 1300° C. and subsequently cold working the first blank.

9. The method as claimed in claim 1 , wherein producing the first blank corresponding to the piston main body includes forging the first blank via a hot working method at a temperature ranging from 1200° C. to 1300° C., after which the first blank is cold calibrated at a temperature of 150° C. or less.

10. The method as claimed in claim 1 , wherein producing the first blank corresponding to the piston main body includes forging the first blank via a warm working method at a temperature ranging from 600° C. to 900° C.

11. The method as claimed in claim 10 , further comprising cold working the first blank at a temperature of 150° C. or less after performing the warm working method.

12. The method as claimed in claim 1 , wherein producing the first blank corresponding to the piston main body includes forging the first blank via a cold working method at a temperature of 150° C. or less.

13. The method as claimed in claim 1 , wherein the combustion depression is disposed asymmetrical with respect to a piston central axis.

14. The method as claimed in claim 1 , wherein the combustion depression is disposed radially offset with respect to a piston central axis.

15. The method as claimed in claim 1 , wherein the combustion depression is disposed inclined with respect to a piston central axis.

16. The method as claimed in claim 1 , wherein the first blank and the second blank each include a plurality of welding surfaces, the first blank including a first welding surface on the first cooling duct region and a second welding surface on a radially outer side opposite of the combustion depression with respect to a piston central axis, and the second blank including a third welding surface on the second cooling duct region and a fourth welding surface in a region of the piston crown on a side radially inwards of the fire land; and
wherein step d) further includes connecting the machined first blank and the machined second blank via welding the first welding surface of the machined first blank to the third welding surface of the machined second blank and the second welding surface of the machined first blank to the fourth welding surface of the machined second blank.

17. The method as claimed in claim 1 , wherein the contour of the combustion depression is finished via forging in step a).

18. A method for producing a piston for an internal combustion engine, comprising the steps of:
a) producing a first blank corresponding to a piston main body via a deformation process, wherein producing the first blank corresponding to the piston main body includes providing a combustion depression defining a contour having a dome and a plurality of piston bosses connected to one another via a running surface, the contour of the combustion depression being fully produced, and wherein producing the first blank further includes forming a first weld surface on a radially outer side opposite of the combustion depression with respect to a piston central axis;
b) producing a second blank corresponding to a piston ring part via at least one of a deformation process and a casting process, wherein producing the second blank corresponding to the piston ring part includes providing a piston crown, an annular fire land and an annular ring section arranged away from a region of combustion with respect to the fire land, and wherein producing the second blank further includes forming a second welding surface in a region of the piston crown on a radially inner side opposite of the annular fire land with respect to the piston central axis;
c) pre-machining the first blank and the second blank and finish machining the first welding surface and the second welding surface to form a machined first blank and a machined second blank, wherein the machined first blank has a first cooling duct region and

Assignees

• Mahle Int Gmbh

Inventors

• Berr Gerhard
• Boczek Sascha-Oliver
• Mueller Reiner
• Scharp Rainer

Classifications

• F02F2003/0061

  by welding · CPC title

• F02F3/22

  the fluid being liquid · CPC title

• F02F3/003

  the parts being connected by casting, brazing, welding or clamping · CPC title

• B23K2101/003

  Pistons · CPC title

• B23B2215/245

  Pistons · CPC title