US 6,155,157 AGranted

Method and apparatus for making a two piece unitary piston

AssigneeCaterpillar Inc.

InventorMark W. Jarrett

Life of this patent

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Abstract

Past pistons have been susceptible to reduced longevity due to increased forces of combustion thereon during operating cycles of an engine. The present two piece unitary piston increases the longevity of pistons used with increased forces of combustion. For example, a head member has a crown portion defining a ring band portion having a bottom surface and a support portion. And, a skirt member defines a ring band support surface and a top surface. The head member and the skirt member have a preestablished material strength being generally the same. The head member and the skirt member are joined by an inertia welding process. The force of combustion acting on the crown portion is resisted by the ring band support surface being in contacting relationship with the bottom surface. Thus, the skirt member structure supports and resists the bending moment of the combustion forces on the head member.

Claims11

Dependent claims

A two piece unitary piston being adapted for use with an engine, said two piece unitary piston comprising:

a head member being made of a material having a preestablished material strength, having a crown portion to which is connected a ring band portion having a plurality of ring grooves therein, defining a bottom surface being axially positioned below said plurality of ring grooves and having a support portion defining a mating surface having a preestablished surface area;
a skirt member being made of a material having a preestablished material strength being substantially the same as the preestablished material strength of said head member, having a ring band support surface being aligned with the bottom surface and having a top surface being aligned with said mating surface said skirt member being void of a ring groove;
said head member and said skirt member being joined forming said two piece unitary piston, said joining being at the interface of said bottom surface and said mating surface, and said ring band support surface and said top surface respectively;
and
said joining being formed by an inertia welding process.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/167,444Filed 6 Oct 1998
Granted: 5 Dec 2000
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

F02B 23/0696
The combustion space being arranged in working piston: w-piston bowl, i.e. the combustion space having a central projection pointing towards the…
B23P 15/10
Making specific metal objects by operations not covered by a single other subclass or a group in this subclass: pistons
F02F 3/003
Multi-part pistons: the parts being connected by casting, brazing, welding or clamping
F02B 23/0621
Having in-cylinder means to influence the charge motion: squish flow