Closed gallery monobloc piston having oil drainage groove

• US 6,557,514 B1
• Filed: 09/24/2002
• Issued: 05/06/2003
• Est. Priority Date: 10/23/2001
• Status: Expired due to Term

• Current Assignee: Federal-Mogul World Wide LLC (Apollo Global Management, Inc.)
• Original Assignee: Federal-Mogul Worldwide Incorporated (Apollo Global Management, Inc.)
• Inventors: Gaiser, Randall R.
• Primary Examiner(s): MCMAHON, MARGUERITE J
• Application Number:
  US10/253,786
• Publication Number:
  US 20030075137A1
• Time in Patent Office: 224 Days
• Field of Search: 123/193.6, 921/86, 922/06, 922/08
• US Class Current: 123/193.6
• CPC Class Codes: F01M 2001/083 for lubricating cylinders
• CPC Class Codes: F02F 2003/0007 Monolithic pistons; One piece constructions; Casting of pistons
• CPC Class Codes: F02F 3/00 Pistons
• CPC Class Codes: F02F 3/22 the fluid being liquid
• CPC Class Codes: F16J 1/08 Constructional features providing for lubrication

Abstract

A monobloc piston has a piston head with a combustion bowl formed in its upper surface and a plurality of ring grooves formed in an outer surface of a ring belt. An oil cooling gallery is formed in the piston head which is defined in part by a wall of the combustion bowl and ring belt. The piston has a unitized, immovable piston skirt which is formed as one piece with the pin bosses and fixed at its upper end to the ring belt. Piston rings are disposed in each of the ring grooves, and the piston head is further formed with an oil drainage groove which is located below the lowest of the ring grooves. The oil drainage groove is closed in the vicinity between adjacent pin bores but is open across outer side faces of the pin bores such that oil collected in the oil drainage is drained to the crank case across the open side faces to better manage the flow of oil scraped from the walls of the piston cylinder during operation of the piston to reduce oil consumption and hydrocarbon emissions.

Claims

1. A monobloc piston assembly comprising:

a piston head having a combustion bowl formed in an upper surface thereof and a ring belt formed with a plurality of ring grooves in an outer surface of said ring belt;

a plurality of piston rings disposed in said ring grooves;

an oil cooling gallery formed in said piston head adjacent said combustion bowl and said ring belt;

a pair of pin bosses extending from said piston head formed with axially aligned pin bores and having axially oppositely facing outer surfaces;

a piston skirt formed as one immovable piece with said pin bosses and united at an upper end thereof to said ring belt; and

an oil drainage groove formed in said piston head at a location below said ring grooves, said oil drainage groove being free of any piston rings and being open to said outer surfaces of said pin bosses, said oil drainage groove including a bottom wall that extends substantially circumferentially continuously between said pin bosses and which is interrupted by said outer surfaces of said pin bosses.

2. The assembly of claim 1 wherein said oil cooling gallery includes a bottom wall.

3. The assembly of claim 2 wherein said oil drainage groove is radially aligned with said bottom wall of said oil cooling gallery.

4. The assembly of claim 1 wherein said oil drainage groove is closed to said oil cooling gallery and to an interior of said skirt.

5. The assembly of claim 1 wherein said oil drainage groove includes an upper wall that is circumferentially continuous about said piston head.

6. The assembly of claim 1 wherein said oil drainage groove has bottom wall floor surface spaced above said pin bores.

7. The assembly of claim 1 wherein said oil drainage groove is continuous with said ring belt and said skirt.

8. A method of fabricating a monobloc piston comprising:

forming a piston head having a combustion bowl in a top surface and forming a plurality of ring grooves in an outer surface of a ring belt;

forming an oil cooling gallery in the piston head and providing pin bores in a pair of pin bosses extending from the piston head opposite the combustion chamber;

forming outer side surfaces on the pin bosses that are recessed inwardly of the outer surface of the ring belt;

forming a piston skirt as a one piece immovable structure relative to the piston body and pin bosses;

forming an oil drainage groove in the piston head that is continuous between the pin bosses and is discontinuous and open across the side surfaces of the pin bosses; and

disposing piston rings in the ring grooves while leaving the oil drainage groove free of any piston rings.

9. A monobloc piston assembly comprising:

a piston head having a combustion bowl formed in an upper surface thereof and a ring belt formed with a plurality of ring grooves in an outer surface of said ring belt;

a plurality of piston rings disposed in said ring grooves;

an oil cooling gallery formed in said piston head adjacent said combustion bowl and said ring belt;

a pair of pin bosses extending from said piston head formed with axially aligned pin bores and having axially oppositely facing outer surfaces;

a piston skirt formed as one immovable piece with said pin bosses and united at an upper end thereof to said ring belt; and

an oil drainage groove formed in said piston head at a location below said ring grooves, said oil drainage groove being free of any piston rings and being open to said outer surfaces of said pin bosses, said oil drainage groove is closed to said oil cooling gallery and to an interior of said skirt.