Research On The Key Technology In The Design Of Loudspeaker Cone Surface

Manufacturing informatization plays a very important role in improving theinnovation ability of the enterprises, accelerating the development of the new products,solving the information-island. China is the main but not the powerful manufacturer ofelectroacoustic products in the world, therefore it is essential to apply CAD/CAM/CAEtechnologies to the process of the design and development widely. Cone is the mostfundamental acoustic component of the speaker and has the fatal influence on thespeaker's frequency response property. The research on geometric modeling of the coneis insufficient at present. Based on the computer aided geometric design, the unifiedmodeling of geometric model for the cone surface, the modification of local shape, thecontrolling of section curve for the cone surface and the designing of non-equidistantcurve and surface are investigated.(1) The cone surface is expressed as a uniform mathematical model withCoons and Hermite interpolation method. The shape controlling factor isintroduced in the model to control its local shape and consequently modifythe shape of the cone surface.(2) The height of chord is adopted to control the section curve of the cone. Thecalculation method on the control vertex and weights of merging twoBezier curves into a NURBS curve is studied, so that the cone can bedescribed with a NURBS curve uniformly rather than several curvespiecewise to facilitate control of the cone surface shape, geometricoptimization and integration with CAD/CAM/CAE system effectively. (3) The concept of non-equidistant curve of planar curve is defined based onthe envelope principle. The analytical equation of the non-equidistant curveis derived. And some properties of the non-equidistant curve are proved.The generalized involute is introduced and that the non-equidistant curveof a circle is a generalized involute is presented and applied to themodelling of non-equidistant curves. The application of the abovetheoretical efforts to the design of the non-equidistant surface of conesurface is investigated in detail.