Composite ceramic/metal piston assembly and method of making
This patent describes an integrally cast composite assembly of a cylindrical cap attached to a piston having a higher thermal expansion characteristic than the cylindrical cap, the cap being adapted to receive a ceramic insert, comprising: (a) a piston body comprised substantially as a body of revolution about an axis and comprised of a material having a higher thermal expansion characteristic than the cylindrical cap. The piston body has a crown top and an annular crown side wall with an upper edge, and an annular undercut surface terminating the crown side wall. The undercut surface makes an angle with a plane extending perpendicular to the axis and passing through the upper edge of the crown side wall. The angle is substantially equal to the arc tangent of H/R where H is the median distance of the undercut surface from the plane and R is the median radius fo the undercut surface from the axis of the piston; and (b) a cylindrical cap disposed on the piston crown top and having a cap side wall depending about the crown side wall, the cap side wall having an annular lip extending radially inwardly from the cap side wall. The lip has surface mateable with the undercut surface of the piston body so that there exists a tightly stressed camming relationship between the mateable surfaces as a result of the shrinkage of the piston body upon solidification.
- Assignee:
- Ford Motor Co., Dearborn, MI
- Patent Number(s):
- US 4649806
- OSTI ID:
- 6873412
- Resource Relation:
- Patent File Date: Filed date 4 Apr 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
CERAMICS
MOLDING
COMPOSITE MATERIALS
INTERNAL COMBUSTION ENGINES
PISTONS
VEHICLES
CASTING MOLDS
CONSTRUCTION
INCIDENCE ANGLE
METALS
SOLIDIFICATION
THERMAL EXPANSION
ELEMENTS
ENGINES
EXPANSION
FABRICATION
HEAT ENGINES
MATERIALS
PHASE TRANSFORMATIONS
330100* - Internal Combustion Engines
360601 - Other Materials- Preparation & Manufacture
360201 - Ceramics
Cermets
& Refractories- Preparation & Fabrication