| 摘要 |
PURPOSE:To improve a radiation effect and forming efficiency by forming a wave-like concave-convex portion having equal pitch on the friction surface of a facing. CONSTITUTION:Wave-like concave portions 3 and convex portions 4 continuously disposed in the peripheral direction are formed at equal spaces on the surface of a facing 1. The concave portion 3 and the convex portion make one set, which is divided into eight equal parts. The concave portion 3 and the convex portion 4 are formed in such a manner as to expand as they are directed from the inner peripheral end surface to the outer peripheral end surface. The depth of the concave portion 3 is less than half the thickness of the convex portion 4 of the facing not to lower the strength. |
