Substantially cylindrical powder compact and die assembly for compacting powder

摘要

The cross-sectional shape of a main part except for both end portions is generally divided into a lower arc surface extending along a base circle and an upper arc surface of which a top portion corresponds to the base circle. Side edge portions extending inward from the base circle are formed on both side surfaces of the upper arc surface. Curved edge portions which concavely curves upward from the side edge portions to end surfaces and continues to the end surfaces and chamfer portions extending from the end surfaces to the side surfaces which planes the edges and curves so that width thereof gradually narrows, are formed on both ends in a longitudinal direction.

主权项

1. A substantially cylindrical powder compact having a substantially cylindrical shape in which a cross sectional outer shape contacts with an inside of a base circle having a substantially circular shape in which a shaft center of the circular shape agrees with the center of the circle,
wherein the cross sectional outer shape is constructed by at least a pair of side edge portions, which are formed on both sides which separate about 180° in a circumferential direction from each other and extend inside from the base circle, an upper arc surface, which connects between inside edges of these side edge portions and contacts with an inside of the base circle at at least a top portion, and a lower arc surface, which connects between outside edges of the side edge portions and contacts with an inside of the base circle at at least a bottom portion, and the powder compact further comprising; a curved surface portion, which concavely curves and rises from each side edge portion to an end surface and continues to the end surface, and a chamfer portion, which planes an edge and gradually narrows from each end surface to a side surface, on both ends in a longitudinal direction of the powder compact.