PISTON ASSEMBLY WITH WELD SUPPORT

• US 20140238232A1
• Filed: 02/21/2014
• Published: 08/28/2014
• Est. Priority Date: 02/22/2013
• Status: Active Grant

• Current Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Original Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Inventors: Lapp, Michael T., Gabriel, Dieter
• Granted Patent: US 9,631,576 B2
• Time in Patent Office: Days
• US Class Current: 92/172
• CPC Class Codes: B23K 2101/003 Pistons
• CPC Class Codes: B23K 2103/10 Aluminium or alloys thereof
• CPC Class Codes: B23K 26/28 of curved planar seams
• CPC Class Codes: B23K 26/32 taking account of the properties of the material involved
• 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 3/16 having cooling means
• CPC Class Codes: F02F 3/22 the fluid being liquid
• CPC Class Codes: Y10T 29/49249 Piston making

Abstract

Exemplary piston assemblies and methods of making the same are disclosed. An exemplary piston may include a piston body defining a piston axis, the piston body having a skirt and forming a lower surface of a cooling gallery. The body may include radially inner and outer body mating surfaces. The piston may further include a cooling gallery ring cooperating with the piston body to form the cooling gallery. The piston body and cooling gallery ring may be joined together along radially inner and radially outer interface regions to form a generally one-piece piston assembly. In some exemplary approaches, mating surfaces of the body and ring may be positioned adjacent a support surface configured to inhibit or prevent weld spatter formed in a process joining the ring and body from the cooling gallery.

Claims

1. A method, comprising:

providing a piston body defining a piston axis and at least a portion of an upper combustion bowl surface, the piston body forming a lower surface of a cooling gallery, the body including radially inner and outer body mating surfaces;

assembling a cooling gallery ring with the piston body, the cooling gallery ring including a radially inner ring mating surface and a radially outer ring mating surface;

laser welding the body to the cooling gallery ring along a radially inner interface region, the radially inner interface region including the radially inner mating surfaces of the body and the cooling gallery ring; and

laser welding the body to the cooling gallery ring along a radially outer interface region, the radially outer interface region including the radially outer mating surfaces of the body and cooling gallery ring;

wherein at least one of the mating surfaces includes a step portion supporting an adjacent interface region between the cooling gallery ring and the piston body.

2. The method of claim 1, wherein the laser welding includes directing a weld laser substantially parallel to the piston axis toward one of the radially inner and radially outer mating surfaces of the body and cooling gallery ring.

3. The method of claim 1, wherein the laser welding includes directing a weld laser in a direction toward one of the radially inner and radially outer mating surfaces of the body and cooling gallery ring, the direction defining a non-parallel angle with respect to the piston axis.

4. The method of claim 1, wherein the piston body includes a skirt configured to interface with an engine bore surface.

5. The method of claim 1, further comprising heating at least one of the body and the cooling gallery ring prior to the laser welding.

6. The method of claim 1, wherein the step portion includes a spatter trap configured to receive weld spatter, the spatter trap defining an enclosed volume adjacent to a weld site associated with one of the radially inner and outer interface regions.

7. The method of claim 1, wherein the piston body and cooling gallery ring are each formed of an aluminum material.

8. The method of claim 1, wherein the radially outer interface region is elongated in a direction parallel to the piston axis.

9. The method of claim 1, further comprising providing at least one support surface adjacent at least one of the mating surfaces.

10. The method of claim 9, wherein the support surface defines at least in part a tortuous path between the at least one of the mating surfaces and the cooling gallery.

11. The method of claim 9, wherein the support surface is configured to inhibit weld spatter from reaching the cooling gallery.

12. A piston assembly, comprising:

a piston body defining a piston axis and at least a portion of an upper combustion bowl surface, the piston body having a skirt and forming a lower surface of a cooling gallery, the body including radially inner and outer body mating surfaces; and

a cooling gallery ring including a radially inner ring mating surface abutted along a radially inner interface region with the radially inner body mating surface, the cooling gallery ring including a radially outer ring mating surface abutted along a radially outer interface region with the radially outer body mating surface such that the cooling gallery is substantially enclosed;

wherein the piston body and cooling gallery ring are welded together along the radially inner and radially outer interface regions; and

wherein at least one of the mating surfaces includes a step portion supporting an adjacent interface region between the cooling gallery ring and the piston body.

13. The piston assembly of claim 12, wherein the body defines a radially outer portion of the combustion bowl surface and the ring defines a radially inner portion of the combustion bowl surface.

14. The piston assembly of claim 12, wherein the body defines an entire portion of the combustion bowl surface.

15. The piston assembly of claim 12, wherein the step portion includes a spatter trap configured to receive weld spatter.

16. The piston assembly of claim 15, wherein the spatter trap defines an enclosed volume adjacent to a weld site associated with one of the radially inner and outer interface regions.

17. The piston assembly of claim 12, further comprising a ring insert received within a piston ring groove, the ring insert defining a cavity configured to retain a piston ring.

18. The piston assembly of claim 12, wherein the piston body and cooling gallery ring are each formed of an aluminum material.

19. The piston assembly of claim 12, wherein at least one of the cooling gallery ring and the piston body defines a support surface adjacent at least one of the mating surfaces.

20. The piston assembly of claim 19, wherein the support surface defines at least in part a tortuous path between the at least one of the mating surfaces and the cooling gallery.