Method for the production of a piston

Patent metadata

Field	Value
Publication number	US-9364923-B2
Application number	US-201414542218-A
Country	US
Kind code	B2
Filing date	Nov 14, 2014
Priority date	May 5, 2011
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

The present invention relates to a method for the production of a piston ( 1 ), composed of a piston upper part ( 2 ) and a piston lower part ( 3 ), of an internal combustion engine, in which the piston upper part ( 2 ) is welded with the piston lower part ( 3 ) via a contact surface ( 4 ) and thereby a cooling duct ( 5 ), delimited therebetween, is formed. It is essential to the invention here that for the production or keeping free of an net opening ( 6 ) and/or of an outlet opening ( 7 ) of the cooling duct ( 5 ) during or immediately after the welding of the piston upper part ( 2 ) with the piston lower part ( 3 ) at least one pin ( 8 ) is held out from the piston lower part ( 3 ) in the cooling duct ( 5 ) or is pushed therein and is drawn out again after the welding process, so that a welding bead ( 9 ) occurring on the welding process does not constrict a cross-section of the net opening ( 6 ) and/or of the outlet opening ( 7 ). Hereby, the piston ( 1 ) can be produced at a comparatively favorable cost.

First claim

The invention claimed is:

1. A clamping device comprising: a first clamping jaw for holding a piston lower part and a second clamping jaw opposite of and adjacent to the first clamping jaw for holding a piston upper part, the piston upper part and the piston lower part forming a cooling duct defining at least one of an inlet opening and an outlet opening, and a welding bead disposed within the cooling duct at a region of the at least one of the inlet opening and the outlet opening;
wherein the first clamping jaw is movable relative to the second clamping jaw such that the first clamping jaw is pressed against the second clamping jaw in a first position and the first clamping jaw is separated from the second clamping jaw in a second position;
wherein the first clamping jaw includes at least one pin insertable into the at least one of the inlet opening and the outlet opening, and wherein the at least one pin is inserted from the first clamping jaw in the cooling duct when the first clamping jaw and the second clamping jaw are in the first position to deform the welding bead disposed within the cooling duct at the region of the at least one of the inlet opening and the outlet opening.

2. The clamping device according to claim 1 , wherein the at least one pin is securely connected with the first clamping jaw holding the piston lower part during a welding process.

3. The clamping device according to claim 1 , further comprising an adjustment device configured to extend and retract the at least one pin relative to the first clamping jaw at least when the first clamping jaw and the second clamping jaw are in the first position.

4. The clamping device according to claim 1 , wherein the at least one pin is moveable by at least one of hydraulically, pneumatically and electrically, and independently of a first clamping jaw.

5. The clamping device according to claim 1 , wherein the at least one of the inlet opening and the outlet opening is unobstructed.

6. The clamping device according to claim 1 , wherein the at least one pin presses the welding bead against a wall of the cooling duct when the first clamping jaw and the second clamping jaw are in the first position.

7. The clamping device according to claim 1 , wherein the at least one pin is tapered at a free end of the at least one pin defining a conical cross-section.

8. The clamping device according to claim 7 , wherein the free end of the at least one pin presses the welding bead against a wall of the cooling duct when the first clamping jaw and the second clamping jaw are in the first position.

9. The clamping device according to claim 1 , wherein the first clamping jaw includes at least two pins, a first pin insertable into the inlet opening and a second pin insertable into the outlet opening.

10. The clamping device according to claim 9 , wherein at least one of the first pin and the second pin is securely connected with the first clamping jaw.

11. The clamping device according to claim 9 , wherein at least one of the first pin and the second pin is adjustable independently of the first clamping jaw.

12. The clamping device according to claim 9 , wherein the at least two pins respectively include an adjusting device configured to at least one of extend and retract the at least two pins at the piston lower part.

13. The clamping device according to claim 1 , wherein the at least one pin extends into the cooling duct an extent at least commensurate with a position of the welding bead.

14. The clamping device according to claim 1 , wherein the first clamping jaw is rotatable relative to the second clamping jaw at least in the first position.

15. A clamping device for a piston, comprising:
a first clamping jaw for mounting a piston lower part and a second clamping jaw opposite the first clamping jaw for holding a piston upper part, the first clamping jaw being rotatable relative to the second clamping jaw, wherein the piston upper part and the piston lower part form an annular cooling duct defining at least one of an inlet opening and an outlet opening, and a welding bead disposed within the cooling duct in a region of at least one of the inlet opening and the outlet opening;
at least one pin extending from the first clamping jaw configured to insert into at least one of the inlet opening and the outlet opening, the at least one pin being tapered at a free end defining a conical cross-section;
wherein the free end of the at least one pin is extendable into the cooling duct via at least one of the inlet opening and the outlet opening an extent at least commensurate with a position of the welding bead.

16. The clamping device according to claim 15 , wherein the at least one pin is arranged adjustably on the first clamping jaw, the at least one pin configured to extend and retract independently of the first clamping jaw.

17. The clamping device according to claim 15 , wherein the at least one pin presses the welding bead against a wall of the cooling duct in a region corresponding to at least one of the inlet opening and the outlet opening.

18. A method for producing a piston, comprising:
mounting a piston lower part via a clamping jaw, wherein the piston lower part includes a circumferential contact surface and at least one of an inlet opening and an outlet opening;
clamping a piston upper part having a complementary circumferential contact surface on the piston lower part and abutting the respective contact surfaces together, wherein the piston lower part and the piston upper part delimit a cooling duct extending about a periphery of the piston, the cooling duct defining at least one of the inlet opening and the outlet opening;
guiding at least one pin extending from the clamping jaw through at least one of the inlet opening and the outlet opening into the cooling duct; and
welding the piston lower part to the piston upper part about the respective contact surfaces to form a connection via rotating the clamping jaw and the piston lower part relative to the piston upper part, wherein a welding bead resulting from welding the piston lower part to the piston upper part projects into the cooling duct at the connection in a region corresponding to at least one of the inlet opening and the outlet opening;
wherein the at least one pin prevents the welding bead from obstructing at least one of the inlet opening and the outlet opening.

19. The method according to claim 18 , wherein guiding the at least one pin includes extending the at least one pin into the cooling duct at least to a position of the connection, and pressing the welding bead via the at least one pin against a wall of the cooling duct at least one of during the step of welding the piston lower part to the piston upper part and after the step of welding the piston lower part to the piston upper part.

20. The method according to claim 18 , wherein the clamping jaw is a first clamping jaw, and wherein clamping the piston upper part includes mounting the piston upper part in a second clamping jaw; and
wherein welding the piston lower part with the piston upper part includes pressing the first clamping jaw against the second clamping jaw and rotating the first clamping jaw relative to the second clamping jaw to produce a friction-welded connection, and pressing the welding bead via the at least one pin against a wall of the cooling duct in the region corresponding to at least one of the inlet opening and the outlet opening.

Assignees

• Mahle Int Gmbh

Inventors

• Boczek Sascha-Oliver

Classifications

• B23K37/053

  aligning cylindrical work; Clamping devices therefor · CPC title

• B23K20/129

  specially adapted for particular articles or work · CPC title

• B23P15/10 Primary

  pistons · CPC title

• F02F3/003

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

• F02F2003/0061

  by welding · CPC title