Development of Design System for Keyboard Rubber Diaphragms
Tei HIRASHIMA and Masaru ZAKO
Abstract:Rubber diaphragms are widely used as elements in the mechanisms of keyboard switches. Generally, in evaluating operational feeling of keyboard switches, it is important to analyze their loading and unloading behavior to establish their force-displacement curve. Loading and unloading behavior of a rubber diaphragm exhibits high non-linearity due to geometric and material effects. In this study, the finite element method is used to analyze the behavior and the analytical results are found to be in full agreement with experimental results. In addition, it is defined that a change of the value of a property parameter against a unit change of the value of a design parameter is a sensitivity coefficient. A Newton-Raphson method using these sensitivity coefficients is applied to modify property parameters towards pre-defined target property parameters. By several results of numerical experiments, it is expected that this design system, which has each property and its design parameter vectors and its sensitivity coefficients matrix in the database, directly gives the designer proper values of design parameters and considerably reduce design times. Key Words:Design system, Finite element method, Sensitivity coefficients, Database, Rubber diaphragm, Force-displacement curve