Abstract: To provide a friction material composition which provides a friction material having high friction coefficient during high speed and high temperature braking, high coefficient of static friction and excellent abrasion resistance at high temperature and causing little sticking due to rust, even when the composition includes no antimony element or no copper element, or includes less than 0.5% by mass of copper element if any, in other words even when having a composition environmentally less harmful or less harmful to the human body. More specifically the friction material composition includes a bonding material, an organic filler, an inorganic filler and a fiber substrate, wherein the friction material composition includes no copper element, or includes less than 0.5% by mass of copper element if any, includes no antimony element, includes 5% by mass or less of iron fiber, 1 to 5% by mass of zinc powder, 2.5 to 6% by mass of calcium hydroxide, 0.7 to 1.

Abstract: A cam lobe piece of a built-up type camshaft for an internal combustion engine. The built-up type camshaft includes a hollow shaft fixedly inserted in a shaft opening of the cam lobe piece upon diametrical expansion of the hollow shaft. The cam lobe piece comprises a base circle section having the shaft opening, and a cam lobe section formed integral with the base circle section.