| 摘要 |
PURPOSE:To control the diameter of a nodal ring according to the degree of inclination, by producing a flat plate giving the compression to the porous resin formed into a rotary trapezoid and giving a continous inclination of density from the center toward the circumference of the flat plate. CONSTITUTION:A chevron part 4a of a porous resin matter 4 formed into a rotary trapezoid using the lower bottoms of trapezoids a, b, c, and d for a rotary shaft A is crashed by the compression to obtain a porous resin flat plate 4' having the same from as a flat plate 4b. Thus the plate 4' is composed of a core material having a continuous inclination of density as shown by a and a characteristic broken line 6 to the displacement toward the diameter in the density characteristic diagram. The inclination of density of the line 6 can be controlled by the ratio between the upper bottoms (distance between a and b) and the lower bottoms (distance between c and d) of the trapezoids, a, b, c and d. In addition, a metallic foil or a plastic film is stuck on a single or both surfaces of the core material as a surface material. |
