Method for producing a piston or piston head for an internal combusition engine

• US 20050028364A1
• Filed: 07/30/2002
• Published: 02/10/2005
• Est. Priority Date: 09/19/2001
• Status: Abandoned Application

• Current Assignee: Mahle GmbH (MAHLE-STIFTUNG GmbH)
• Original Assignee: Mahle GmbH (MAHLE-STIFTUNG GmbH)
• Inventors: Issler, Wolfgang
• Application Number:
  US10/490,273
• Publication Number:
  US 20050028364A1
• Time in Patent Office: Days
• US Class Current: 29/888.42
• CPC Class Codes: B21K 1/18 pistons or plungers
• CPC Class Codes: B21K 25/00 Uniting components to form integral members, e.g. turbine wheels and shafts, caulks with inserts, with or without shaping of the components uniting by interference- or press-fitting B23P11/02, B21K19/02
• CPC Class Codes: B23P 15/10 pistons
• CPC Class Codes: F02B 23/0603 at least part of the interior volume or the wall of the combustion space being made of material different from the surrounding piston part, e.g. combustion space formed within a ceramic part fixed to a metal piston head
• CPC Class Codes: F02B 23/0696 W-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder wall
• CPC Class Codes: F02F 2200/04 Forging of engine parts
• CPC Class Codes: F02F 3/045 the inserts being located in the crown
• CPC Class Codes: F02F 3/12 on piston heads
• CPC Class Codes: F05C 2201/0448 Steel
• CPC Class Codes: F05C 2201/0466 Nickel
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y10T 29/49249 Piston making
• CPC Class Codes: Y10T 29/49252 Multi-element piston making
• CPC Class Codes: Y10T 29/49256 with assembly or composite article making
• CPC Class Codes: Y10T 29/49263 by coating or cladding

Abstract

The invention relates to a method for producing a piston or piston head with a combustion relief (6) for an internal combustion engine. The aim of the invention is to easily and economically produce pistons having a reduced tendency to scale at the edge of the combustion relief. To this end, the piston is formed from a cylindrical unmachined part (1) made of steel, whereby the rod section has at least one front face (2). The method is characterized by the following steps: A) forming an annulary encircling recess (3) in the front face (2); B) introducing additional material (4) into the recess (3); connecting the additional material (4) to the steel of the unmachined part (1) in an at least partially non-positive manner; C) forging the unmachined part (1), which is formed according to steps A) and B), into a piston blank (5), and; D) machining the piston blank (5) into a piston (10) that is ready to be installed in an internal combustion engine.

Claims

1. Method for the production of a piston (10) or piston head for an internal combustion engine, having a combustion bowl (6) provided on the piston head, in which the piston (10) is formed from a cylindrical unfinished part (1) made of steel, whereby the cylindrical unfinished part (1) has at least one flat face (2) that is formed at a right angle to the longitudinal axis (9) of the unfinished part (1), characterized by the steps:

A) forming a ring-shaped, circumferential recess (3) in the face (2);

B) applying additional material (4) into the recess (3), by means of an at least partially non-positive connection between the additional material (4) and the steel of the unfinished part (1);

C) forging the unfinished part (1) produced according to steps A) and B) to produce a piston blank (5);

D) machining the piston blank (5) to produce a finished piston (10), ready for installation in the internal combustion engine.

2. Method according to claim 1, wherein the ring-shaped recess (3) is made in a region of the face (2), positioned in such a manner that in the finished piston (10), it lies in the edge region (6a) of the combustion bowl (6).

3. Method according to claim 1, wherein the additional material (4) is applied by means of welding, whereby the ring-shaped recess (3) is completely filled with additional material (4).

4. Method according to claim 3, wherein the welding takes place by means of CO2 welding, laser welding or electron beam welding, friction welding, explosion plating.

5. Method according to claim 1, wherein the cylindrical unfinished part (1) is formed from a 42CrMo4 or 38MnSi6 material of AFP steel, and that the additional material is formed from a material that demonstrates no tendency or only a slight tendency to form an oxidation layer at a stress temperature in the internal combustion engine of more than 450°

C.

6. Method according to claim 5, wherein the additional material is an oxidation-resistant material such as valve steel X45CrSi9 or a material on a nickel basis.

7. Method according to claim 1, wherein a piston (10) ready for installation is produced, leaving out the method step A), in such a manner that the application of additional material takes place in a circular region on the face (2), by means of an at least partially non-positive connection, which region lies in the edge region of the combustion bowl of the finished piston.

8. Method according to claim 1, wherein the edge region of the combustion bowl (6a) is not formed of the additional material (4) over the entire circumference of the combustion bowl (6).

9. Method according to claim 1, wherein a piston (10) ready for installation is produced, leaving out the method step A), in such a manner that the application of additional material (4) takes place over the entire face (2), by means of an at least partially non-positive connection.

10. Method according to claim 9, wherein the additional material (4) increases from the piston axis (9) radially outward up to the piston edge.

11. Method according to claim 9, wherein the additional material (4) forms the entire surface of the piston head at least a part, particularly the bowl edge region (6a), of the finished piston (10), and comprises at least part of the fire ridge.