| 摘要 |
PURPOSE:To give an enhanced strength and abrasive resistance to a valve seat made of two different sintered alloys impregnated with copper alloy by specifying the amount of sintering voids in each sintered alloy and by normalizing the balance between the amounts of these sintering voids. CONSTITUTION:A compound sintered valve seat composed of two layers, No.1, No.2 members 1 and 2 is used as a valve seat to be furnished at the intake/ exhaust port's opening fronting toward the combustion chamber, formed at the cylinder head 3 of an internal combustion engine. As the sintered alloy to form No.1 member 1 of the valve 4 on its contact surface side is used a ferric type sintered alloy, which includes 8-12vol.% the hardqparticles with sizes below 250 mesh, has atomized iron powder as the base, and contains an amount of voids in 6-14vol.%. As the sintered alloy to form No.2 member 2 is used a ferric type sintered alloy, which includes 0.5-1.4w% of carbon, 0.1-0.4w% of phosphor, and iron as the residues, and which contains 6-12vol.% of voids formed by atomized powder. |
