STRESS CALCULATING METHOD OF NOZZLE FOR INJECTION MOLDER, AND NOZZLE BASED THEREON

摘要

PROBLEM TO BE SOLVED: To calculate the stress at the corner part of the edge face of an opening part by a method wherein the stress is obtained by multiplying the value of the circumferential stress of a cylinder, which is obtained through the formula on a thick cylinder under the supposition that the cylinder has a crosssection having the same as that of the edge face of the opening part, with a function, which is obtained through a structural analysis, as a factor. ;SOLUTION: Under the supposition that a cylinder has a crosssection having the same as that of the edge face 6 of an opening part, the circumferential stress δ of the cylinder is calculated from a formula: δ=P(D²+d²)/(D²-d²)×P, in which P is the resin pressure (kgf/ cm²) of a molten resin, D (cm) is the outer diameter of the edge face 6 of the opening part, (d) (cm) is its inner diameter, t(cm)=(D-d)/2 is the wall thickness of an imaginary cylinder. A function (f) for mating the value obtained from the formula with the group of the stress values of the corner part of the edge face of the opening part, which are obtained through a large number of structural analyses carried out under the condition that the value of (d) or D are varied, is found out. By multiplying the formula with the (f) value as a factor, the stresses of the corner of theedge face of the opening part in the range of the ratio t/d or the ratio of the thickness of the edge face of the opening part to its inner diameter of 0.1-0.3 are obtained.;COPYRIGHT: (C)1998,JPO