| 摘要 |
<p>An integrally cast composite piston assembly is disclosed which is effective to carry a ceramic plate in an iron based cap. The assembly comprises a cylindrical piston body, preferably of aluminum, having a crown top, an annular crown side wall with an upper edge, and an annular undercut surface terminating the crown side wall. The undercut surface must make an angle with a plane extending perpendicular to the axis of the piston, the angle being 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 of the undercut surface from the axis of the piston. The assembly further comprises the cylindrical iron-based cap disposed on the piston body 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 having a 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.</p> |
