Hollow piston for a piston engine and method for producing a hollow piston

• US 6,662,709 B1
• Filed: 01/04/2002
• Issued: 12/16/2003
• Est. Priority Date: 07/21/1999
• Status: Expired due to Fees

• Current Assignee: Brueninghaus Hydromatik GmbH (Robert Bosch GmbH)
• Original Assignee: Brueninghaus Hydromatik GmbH (Robert Bosch GmbH)
• Inventors: Beutler, Gerhard
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): Lazo, Thomas E.
• Application Number:
  US10/019,737
• Time in Patent Office: 711 Days
• Field of Search: 921/72, 921/76, 921/87, 922/60, 298/880.42, 298/880.44, 298/880.47
• US Class Current: 92/176
• CPC Class Codes: F04B 1/124 Pistons
• CPC Class Codes: Y10T 29/49252 Multi-element piston making
• CPC Class Codes: Y10T 29/49256 with assembly or composite article making

Abstract

A hollow piston (1) piston engine including a closed annular cavity (9). Said hollow piston constituted of a first piston part (1a) with a base section (3) from which a joint part (4) extends in one axial direction, and from which a peripheral wall (6) that delimits the annular cavity (9) on the outside, and a mandrel (7) that delimits the annular cavity (9) on the inside extend, each as one piece, in the other axial direction. The hollow piston is also constituted of a second piston part (1b) having a cover (8) which is connected to the ends of the peripheral wall (6) and of the mandrel (7), said ends facing away from the base section (3). In order to achieve an economical and simple production while ensuring the provision of a stabile construction, the peripheral wall (6) and the mandrel (7) are formed on the base section (3) without machining.

Claims

1. Process for manufacturing a hollow piston (1) for a piston engine, having a closed annular cavity (9), comprising the following process steps:

constructing a first piston part (1a) with a diametral oversize (x) with a base section (3) from which a joint part (4), or a material extension for the said joint part (4), extends in one axial direction, and from which a peripheral wall (6) that delimits the annular cavity (9) on the outside and a mandrel (7) that delimits the annular cavity (9) on the inside extent in the other axial direction, in one piece in each case,

constructing a second piston part (8) with a diametral oversize (x) in the form of a cover (8),

connecting the first and second piston parts (1a, 8), by friction welding,

and finally machining the superficies (18) of the hollow piston (1) or of the joint part (4), wherein the peripheral wall (6) and the mandrel (7) are simultaneously formed on the base part (3) through extrusion.

2. Process according to claim 1, wherein the cover (8) is constructed with a peripheral wall section (6a) that delimits the annular cavity (9) on the outside, and with a mandrel section (7a) that delimits the annular cavity (9) on the inside, and the peripheral wall section (6a) and the mandrel section (7a) are simultaneously formed on the cover (8) through extrusion.

3. Process according to claim 1 or 2, wherein the peripheral wall (6), the peripheral wall section, sections (6a, 6b), and the mandrel (7), the mandrel section, and sections (7a, 7b) are selectively formed on through cold extrusion.

6. Process according to claim 2 or 5, wherein the base section (3) and the cover (8) are constructed with peripheral wall sections (6a, 6b) and mandrel sections (7a, 7b) of equal length.

8. Process according to any one of claims 1, 2 or 4, wherein the peripheral wall (6), the peripheral wall section, sections (6a, 6b), the mandrel (7), and the mandrel section and sections (7a, 7b) are formed on through cold extrusion.

9. Process according to any one of claims 1, 2 or 4, wherein the first piston part (1a) with the peripheral wall (6), peripheral wall section (6b), mandrel (7), mandrel section (7b), and the second piston part (1b) with the peripheral wall section (6a) and mandrel section (7a), are formed by sintering.

10. Process according to claim 1, wherein identical prefabricated parts are used for the first piston part (1a) and the second piston part (1b).

4. Process for manufacturing a hollow piston (1) for a piston engine, having a closed annular cavity (9), comprising the following process steps:

constructing a first piston part (1a) with a diametral oversize (x) with a base section (3) from which a joint part (4), or a material extension for the said joint part (4), extends in one axial direction, and from which a peripheral wall (6) that delimits the annular cavity (9) on the outside and a mandrel (7) that delimits the annular cavity (9) on the inside extent in the other axial direction, in one piece in each case,

constructing a second piston part (8) with a diametral oversize (x) in the form of a cover (8),

connecting of the first and second piston parts (1a, 8), by friction welding,

and finally machining of the superficies (18) of the hollow piston (1) or of the joint part (4), wherein the first piston part (1a) with the peripheral wall (6) and mandrel (7) are formed by sintering.

5. Process for manufacturing a hollow piston (1) for a piston engine, having a closed annular cavity (9), comprising the following process steps:

constructing of a first piston part (1a) with a diametral oversize (x) with a base section (3) from which a joint part (4), or a material extension for the said joint part (4), extends in one axial direction, and from which a peripheral wall (6) that delimits the annular cavity (9) on the outside and a mandrel (7) that delimits the annular cavity (9) on the inside extend in the other axial direction, in one piece in each case,

constructing a second piston part (8) with a diametral oversize (x) in the form of a cover (8),

connecting the first and second piston parts (1a, 8), by friction welding,

and finally machining of the superficies (18) of the hollow piston (1) or the joint part (4), wherein the cover (8) is constructed with a peripheral wall section (6a) that delimits the annular cavity (9) on the outside, and with a mandrel section (7a) that delimits the annular cavity (9) on the inside, and the peripheral wall section (6a) and the mandrel section (7a) are simultaneously formed on the cover (8) and the first piston part (1a) with the peripheral wall section (6b) and mandrel section (7b), and the second piston part (1b) with the peripheral wall section (6a) and mandrel section (7a), are selectively formed by sintering.

7. Process for manufacturing a hollow piston (1) for a piston engine, having a closed annular cavity (9), comprising the following process steps:

constructing a first piston part (1a) with a diametral oversize (x) and with a base section (3) from which a joint part(4), or a material extension for the said joint part (4), extends in one axial direction, and from which a peripheral wall section (6b) that delimits the annular cavity (9) on the outside and a mandrel section (7b) that delimits the annular cavity (9) on the inside extend in the other axial direction, in one piece in each case,

constructing a second piston part (1b) with a radial oversize (x) in the form of a cover (8) with a peripheral wall section (6a) that delimits the annular cavity (9) on the outside, and with a mandrel section (7a) that delimits the annular cavity (9) on the inside, said first piston part (1a) and said second piston part (1b) being formed from identical prefabricated parts,

connecting the peripheral wall sections (6a, 6b) and the mandrel sections (7a, 7b), by welding,

and finally machining of the superficies (18) of the hollow piston (1) or else of the joint part (4), wherein the peripheral wall sections (6a, 6b) and the mandrel sections (7a, 7b) are each constructed with an equal axial length.