Patent ID: 7041149
Filing Date: 2006-05-09
Classification: B22F,C22C,F01L,F16H

Abstract:
1. A sintered sprocket for a silent chain in a crankshaft, a cam shaft, a balancer shaft, or a water pump shaft of an internal combustion engine, composed of a sintered alloy selected from one of (1) to (3), the sprocket being densified to have a relative density of 95% or higher in a surface layer of gear teeth by forming by rolling, at least the gear surface having only a martensite structure and having a surface hardness of 700 HV or higher: (1) an Fe—Mo—C based sintered alloy containing Mo at 1.0 to 2.0% by mass; (2) an Fe—Mo—Ni—C based sintered alloy containing Mo at more than 1.0 and not more than 2.0% by mass, and Ni at more than 1.0 and not more than 2.5% by mass, or (3) an Fe—Mo—Ni—Cu—C based sintered alloy containing Mo at 0.3 to 1.0% by mass, Ni at not less than 1.5 to less than 3.0% by mass, and Cu at 1.0 to 2.5% by mass.