Synthesis of Spatial Mechanisms with Consideration of Interference of Structural Elements.

Abstract

In the present paper, regarding spatial mechanisms with prismatic and sphere-groove pairs on the coupler, an arrangement system of structural elements for the mechanism with consideration of mutual interferences among links is investigated. In order to determine optimum profiles of links which avoid mutual interferences among the structural elements, such as pairing shafts, pairs and links in the mechanisms, a rotary plane which is arbitrarily fixed on one of the moving links in the mechanism is introduced, and relative loci of pairing points and relative positions of each link with this plane are analyzed. Furthermore, conditions to determine arrangements of links and pairs avoiding mutual interferences of moving links are formulated. Based on the above analytical results, an element-arrangement system is constructed which obtains the optimum profiles and arrangements of links and pairs of spatial mechanisms. Applying the system, a spatial 4-bar mechanism with a prismatic and sphere-groove pairs on the coupler is synthesized as a practical example.