PISTON AND METHOD OF MAKING A PISTON

• US 20140202404A1
• Filed: 01/21/2014
• Published: 07/24/2014
• Est. Priority Date: 01/21/2013
• Status: Active Grant

• Current Assignee: Tenneco Incorporated (Apollo Global Management, Inc.)
• Original Assignee: Federal-Mogul Corporation (Apollo Global Management, Inc.)
• Inventors: Weinenger, Michael, Muscas, Florin
• Granted Patent: US 10,082,102 B2
• Time in Patent Office: Days
• US Class Current: 123/41.35
• CPC Class Codes: B23K 20/129 specially adapted for particular articles or workpieces
• CPC Class Codes: F02F 2003/0061 by welding
• CPC Class Codes: F02F 3/22 the fluid being liquid
• CPC Class Codes: F02F 3/26 having combustion chamber in piston head the surface thereof being covered F02F3/14
• CPC Class Codes: F02F 3/28 Other pistons with specially-shaped head
• CPC Class Codes: F16J 1/22 with universal joint, e.g. ball-joint
• CPC Class Codes: Y10T 29/49252 Multi-element piston making

Abstract

A monobloc piston assembly for an internal combustion engine is provided. The piston assembly includes a piston body which extends along an axis and is formed of at least two pieces of material which are joined together at least one friction weld joint which extends continuously through an annular shape around the axis. One of the pieces has an upper surface with a combustion bowl having a rotationally asymmetrical shape around the axis formed therein. Another of the pieces has a dome-shaped receiving surface which is rotationally symmetrical around the axis for slidingly receiving a portion of a connecting rod.

Claims

1. A monobloc piston assembly for an internal combustion engine, comprising:

a piston body extending along an axis, said piston body being formed of at least two pieces of material joined together by at least one weld joint which extends continuously through an annular shape around said axis;

one of said pieces having an upper surface with a combustion bowl formed therein, said combustion bowl having a rotationally asymmetrical shape around said axis; and

another of said pieces having a dome-shaped receiving surface for slidingly receiving a portion of a connecting rod, and wherein said dome-shaped receiving surface is rotationally symmetrical about said axis.

2. The monobloc piston assembly as set forth in claim 1 wherein said at least one weld joint is a friction weld joint.

3. The monobloc piston assembly as set forth in claim 1 further including a connecting rod having an end with a profile that at least partially matches a profile of said dome-shaped receiving surface of said piston body.

4. The monobloc piston assembly as set forth in claim 2 further including a cap which is joined with said piston body and captures said end of said connecting rod while allowing pivoting thereof in at least one rotational direction.

5. The monobloc piston assembly as set forth in claim 4 wherein said cap allows rotation of said connecting rod relative to said piston body in only one rotational direction.

6. The monobloc piston assembly as set forth in claim 5 wherein said cap has a generally U-shaped opening for allowing said connecting rod to rotate relative to said piston body in said only one rotational direction.

7. The monobloc piston assembly as set forth in claim 4 wherein said cap is joined with said piston body through at least one fastener.

8. The monobloc piston assembly as set forth in claim 4 wherein said end of said connecting rod is generally ball-shaped.

9. The monobloc piston assembly as set forth in claim 4 wherein said end of said connecting rod is generally lollipop shaped.

10. The monobloc piston assembly as set forth in claim 4 wherein said end of said connecting rod has a portion with a semi-spherical surface which extends between opposing flat side surfaces.

11. The monobloc piston assembly as set forth in claim 1 wherein said at least one friction weld joint is a pair of friction weld joints spaced radially from one another on opposite sides of a cooling oil gallery.

12. The monobloc piston assembly as set forth in claim 1 wherein the at least one of said first and second pieces with said dome-shaped receiving surface also has a circumferentially continuous skirt.

13. A method of making a piston, comprising the steps of:

preparing a first piece of a piston body, the first piece having a combustion bowl formed in an upper surface thereof, and the combustion bowl having a rotationally asymmetrical shape about an axis;

preparing a second piece of the piston body; and

welding the first and second pieces of the piston body together.

14. The method as set forth in claim 13 wherein the second piece has a dome-shaped receiving surface with a rotationally symmetrical shape before the step of welding the first and second pieces of the piston body together.

15. The method as set forth in claim 13 wherein the step of welding the first and second pieces of the piston body together is further defined as friction welding the first and second pieces of the piston body together.

16. The method as set forth in claim 13 wherein the second piece has a circumferentially continuous skirt.

18. The method as set forth in claim 13 further including the step of positioning an end of a connecting rods into engagement with the dome-shaped receiving surface of the piston body, wherein the end of the connecting rod has a profile that at least partially matches a profile of the dome-shaped receiving surface to allow rotation of the connecting rod relative to the piston body.

19. The method as set forth in claim 18 further including the step of joining a cap with the piston body while trapping the end of the connecting rod between the cap and the dome-shaped receiving surface on the piston body.

20. The method as set forth in claim 19 wherein the cap has a generally U-shaped opening to allow rotation of the connecting rod relative to the piston body in only one rotational direction.

17. The method as set forth 13 wherein each of the first and second pieces has a pair of joining surfaces spaced radially from one another and wherein the step of friction welding the first and second pieces together includes friction welding the pieces together at the pairs of joining surfaces.