Patent ID: 7897102
Filing Date: 2011-03-01
Classification: B22F,B29C,F01L

Abstract:
1. A method of making a valve guide for use in an internal combustion engine comprising: (a) Placing a metal powder mixture within an elongated, cylindrical-shaped mold having a longitudinal axis; (b) Applying uniform uniaxial pressure to said powder-filled mold only in a direction substantially perpendicular to said longitudinal axis to cause said powder to be compacted and formed into an elongated, generally cylindrical, solid, non-hollowed compact; (c) Sintering said compact to bond said compacted powder, thereby forming a solid elongated sintered metal blank having a generally cylindrical solid, non-hollowed cross-section and having uniform density and hardness from end to end; (d) Forming said cylindrical sintered metal blank to form an essentially round shape; and (e) Drilling a center hole through said cross-section of said blank following said essentially round shape forming step to produce a valve guide having substantially uniform density and hardness from end to end.