MONOLITE PISTON LASER WELDING SPATTER CONTROL

• US 20140197142A1
• Filed: 01/15/2013
• Published: 07/17/2014
• Est. Priority Date: 01/15/2013
• Status: Active Grant

• Current Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Original Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Inventors: Wilder, Montgomery L.
• Granted Patent: US 9,440,310 B2
• Time in Patent Office: Days
• US Class Current: 219/121.64
• CPC Class Codes: B23K 2101/003 Pistons
• CPC Class Codes: B23K 26/0823 Devices involving rotation of the workpiece
• CPC Class Codes: B23K 26/16 Removal of by-products, e.g. particles or vapours produced during treatment of a workpiece by a fluid stream B23K26/142
• CPC Class Codes: B23K 26/28 of curved planar seams
• CPC Class Codes: B23K 26/70 Auxiliary operations or equipment
• CPC Class Codes: F02F 2003/0061 by welding
• CPC Class Codes: F02F 3/003 the parts being connected by casting, brazing, welding or clamping
• CPC Class Codes: F02F 3/22 the fluid being liquid

Abstract

An exemplary system and method for welding a piston assembly includes a piston assembly having a cooling gallery and a loose granulated medium positioned therein. The cooling gallery is formed by a piston body and a cooling gallery ring, and a welder such as a laser welder is positioned proximate the assembly to weld the piston body to the cooling gallery ring. During welding, the assembly is rotated and the loose granulated medium is caused to remain in a gravitationally low portion of the cooling gallery. The weld is formed in an area proximate the loose granulated medium such that weld spatter emitted during welding is emitted into the loose granulated medium.

Claims

1. A method, comprising:

providing a piston body having a piston axis, the piston body having a cavity forming a portion of a cooling gallery that is circumferentially disposed about the piston axis;

providing a cooling gallery ring;

positioning a loose media within the cavity;

assembling the cooling gallery ring with the piston body to foil a pre-weld assembly, such that the cavity of the piston body and cooling gallery ring cooperate to form the cooling gallery and encompass the loose media;

positioning the pre-weld assembly such that the loose media displaces to a gravitationally low portion of the cooling gallery; and

welding the cooling gallery ring to the piston body to form a weld joint such that weld spatter emitted during welding is emitted into the loose media.

2. The method of claim 1, wherein welding the cooling gallery ring to the piston body comprises directing a laser beam toward a pair of surfaces that include a surface of the cooling gallery ring and a surface of the piston body.

3. The method of claim 1, further comprising positioning the pre-weld assembly such that the piston axis is approximately orthogonal to a direction of gravity.

4. The method of claim 1, further comprising rotating the pre-weld assembly about the piston axis while welding the cooling gallery ring to the piston body such that the loose media shifts within the cooling gallery and remains generally at the gravitationally low portion of the cooling gallery.

5. The method of claim 4, wherein welding the cooling gallery ring to the piston body comprises welding at a location that is approximately centered on a collected mass of the loose media as the loose media shifts within the cooling gallery as a result of rotating the pre-weld assembly.

6. The method of claim 1, wherein positioning the loose media comprises positioning one of a sand material, a ceramic, a porcelain, and an aluminum oxide.

7. The method of claim 1, wherein positioning the loose media comprises positioning granulated material having a diameter less than 2 mm.

8. A method, comprising:

positioning a piston assembly for welding two components thereof, the two components comprising a piston body and a cooling gallery ring, the piston assembly comprising a cooling gallery circumferentially disposed about a perimeter thereof and formed by at least the two components;

orienting the piston assembly such that a granular material positioned within the cooling gallery is displaced to a low gravitational portion of the cooling gallery;

welding the two components together to form a weld joint between the two components, such that weld spatter emitted during welding passes to the granular material.

9. The method of claim 8, wherein welding the two components together comprises directing a laser beam toward a pair of mating surfaces of the cooling gallery ring and the piston body.

10. The method of claim 8, further comprising positioning the piston assembly such that an axis of the piston is approximately orthogonal to a direction of gravity.

11. The method of claim 8, further comprising rotating the piston assembly about the axis of the piston while welding the two components such that the granular material shifts within the cooling gallery and remains generally at the low gravitationally portion of the cooling gallery.

12. The method of claim 11, wherein welding the two components comprises welding at a location that is approximately centered on a collected mass of the granular material as the granular material shifts within the cooling gallery as a result of rotating the piston assembly.

13. The method of claim 8, wherein the granular material comprises one of a sand material, a ceramic, a porcelain, and an aluminum oxide.

14. The method of claim 8, wherein positioning the granular material comprises positioning material having a grain sizes that are less than 2 mm.

15. A system for welding a piston assembly, comprising:

a welding fixture configured to hold a piston pre-weld assembly that is comprised of a piston body and a cooling gallery ring, wherein the piston body and the cooling gallery ring have mating surfaces that, when mated together form a cooling gallery;

a welding device positioned to weld the piston body to the cooling gallery ring at a location where the piston body and the cooling gallery ring meet;

wherein the welding fixture is positioned such that a loose granulated medium positioned within the cooling gallery is located proximate the welding device and proximate the welding location, such that when the piston body is welded to the cooling gallery ring, weld splatter emitted therefrom emits into the loose granulated medium in the cooling gallery.

16. The system of claim 15, wherein the welding device is a laser welder.

17. The system of claim 15, wherein the welding fixture is further positioned such a central axis of the piston pre-weld assembly is approximately orthogonal to a direction of gravity.

18. The system of claim 15, further comprising a controller that is configured to rotate the piston pre-weld assembly such that the loose granulated medium shifts within the cooling gallery and remains generally at a gravitationally low portion of the cooling gallery during rotation.

19. The system of claim 15, wherein the loose media comprises positioning one of a sand material, a ceramic, a porcelain, and an aluminum oxide.

20. The system of claim 15, wherein the loose media comprises positioning granulated material having a diameter less than 2 mm.

21. A pre-weld piston assembly comprising:

a piston body;

a cooling gallery ring, wherein the piston body and the cooling gallery ring have mating surfaces that, when mated together form a cooling gallery;

a loose granulated medium positioned within the cooling gallery and located proximate the mating surfaces, wherein loose granulated medium is positioned such that it is displaced to a low gravitational portion of the cooling gallery.

22. The assembly of claim 21, wherein the loose granulated medium is positioned such that when the piston body is welded to the cooling gallery ring, weld splatter emitted therefrom emits into the loose granulated medium in the cooling gallery.