| 摘要 |
PURPOSE: To manufacture a noise-damped sintered molded part for a transmission by defining each characteristic in an inner rim region and a central region in the axially symmetrical sintered molded part having individual concentric zones of material. CONSTITUTION: The axially symmetrical sintered molded part, which has the individual concentric zones of material and is provided with the center region, the inner rim region close to the axis and the outer region remote from the axis, is made of an iron-based material as a basic material, and manganese, phosphorus and/or boron as an auxiliary material. This sintered molded part is made of the material which has a high strength and being substantially free from voids in the inner rim region thereof and is made of the material being highly porous and comparatively ductile in the central region thereof. The pore volum in the central region is 10 to 50 vol.%. The sintered molded part has smaller Young's modulus than Young's modulus of quenched forged steel. Thus, the sintered molded part for the transmission, which is capable of damping a noise generated when metallic gears are meshed with each other, is obtained. |
