PISTONS

• US 3,596,571 A
• Filed: 07/07/1969
• Issued: 08/03/1971
• Est. Priority Date: 07/15/1968
• Status: Expired due to Term

• Current Assignee: Harold T. Hill, John Robson, Roger A. Day
• Original Assignee: Harold T. Hill, John Robson, Roger A. Day
• Inventors: Hill, Harold T., Robson, John, Day, Roger A.
• Application Number:
  US04/839,515
• Time in Patent Office: 757 Days
• US Class Current: 92/222
• CPC Class Codes: B23K 20/129 specially adapted for particular articles or workpieces
• CPC Class Codes: B23P 15/10 pistons
• CPC Class Codes: F02F 2200/04 Forging of engine parts
• CPC Class Codes: F05C 2201/021 Aluminium
• CPC Class Codes: F05C 2201/0448 Steel
• CPC Class Codes: F05C 2251/042 Expansivity
• CPC Class Codes: F16J 1/001 One-piece pistons

Abstract

This invention relates to a piston for an internal combustion engine, compressor or the like, which is composed of at least two mating parts, for example a light alloy piston body part and a wear-resistant ring groove carrier part or heat-resistant crown part, the parts being permanently assembled together by friction welding. The invention also relates to a method of making such pistons.

Claims

1. A piston including:

a tubular piston body part comprising a heat-treated forging or casting of light alloy, the body part including a sidewall, provided at the end thereof adjacent the crown of the piston with an annular recess;

an annular mating part comprising a piston ring carrier part formed from a wearresistant metal; and

an annular top land part;

the piston ring carrier part being secured in said recess by friction welding, and the top land part being secured in said recess between the ring carrier part and the piston crown by friction welding.

2. A piston as claimed in claim 1, wherein an annular coolant cavity is formed in the piston between the ring carrier part and the body part.

3. A piston as claimed in claim 2, wherein at least one of the ring carrier part and top land part is made from a material selected from the following, namely, steel, stainless steel, bronze and hypereutectic aluminum-silicon alloy, and wherein the body part is formed from a full solution and precipitation heat-treated alloy selected from the following, namely a magnesium alloy and an aluminum alloy.

4. A piston as claimed in claim 3, wherein the top land part is friction welded to the ring carrier part.

5. A piston as claimed in claim 3, wherein the top land part is formed integrally with the ring carrier part.

6. A piston as claimed in claim 1, including an insert friction welded into the piston crown, said insert being made from a heat-resistant metal selected from the group consisting of an aluminum copper-nickel-maganese alloy, sintered aluminum, a nickel alloy and steel.

7. A piston as claimed in claim 6, wherein said insert comprises at least a part of a combustion bowl and a hot spot element.

8. A piston including two mating parts secured together by friction welding, wherein one of the mating parts comprises a tubular light alloy body part, and the other of said mating parts comprises a crown part of substantially the same diameter as the body part, formed from a thermal-shock-resistant metal, and friction welded to the body part, a recess defining an annular coolant passage being formed between the cooperating mating surface of the body part and crown part.

9. A piston including two mating parts secured together by friction welding, wherein one of the mating parts comprises a tubular light alloy body portion including a sidewall and a pair of gudgeon pin bosses, and the other of said parts comprises a tubular bushing friction welded into each gudgeon pin boss of the piston, the mating surfaces of each bushing and boss being tapered or stepped.