轴/径向伸缩式成型鼓的拓扑分析与结构创新

Topological Analysis and Structural Innovation of Axial/Radial Telescopic Tire Building Drum

轴/径向伸缩式成型鼓是一种适用于航空轮胎成型的空间伸缩机构,是一种多环耦合和多重过约束的空间复杂机构,因而其拓扑特性分析是机构学研究的难点问题之一.在系统分析其结构与工作原理的基础上,针对轴向与径向结构对称的特点,将机构拆分为若干子结构,运用反螺旋理论判定各子结构的过约束和公共约束,再逐一组合计算机构的自由度和产生的过约束,得出槽凸轮与小转臂间构成的高副结构使机构产生多重过约束的结论.在此基础上,分析并揭示出槽凸轮仅约束外瓦鼓肩做沿径向平面运动,研究了替代或保留槽凸轮约束功用时支链的施加位置;最后,通过建立支链结构约束螺旋系,构造了支链的可行结构形式,进而得到多种轴/径向伸缩式成型鼓的可行方案.因而为该类成型鼓的创新设计提供了一种新的思路,同时也为结构复杂、多环耦合及多重过约束空间机构的自由度分析提供了一种有效的方法.

Abstract：Axial/radial telescopic tire building drum is a spatial telescopic mechanism used for manufacturingaircraft tires as well as a multi-ring coupling and multi-over constraint spatial complex mechanism,therefore its topological characteristic analysis is one of the difficult problems in the study of mechanism. According to the characteristics of axially and radially symmetrical structure,the mechanism is decomposed into several substructures by systematicallyanalyzing its structure and working principle. The over constraints and common constraints of each substructure are judged by utilizing constraint screw theory,and then mobility and over constraints of the mechanism are calculatedby combining the substructures one by one. It is concluded that the multi-over constraint of the mechanism is from thehigh-pair between slot cam and rotating arm. On this basis,it is analyzed and revealed that the slot cam only restricts the external drum-shoulder to move in the radial plane,and applied position of limb is studied when the constraint function of the slot cam is replaced or retained;Finally,feasible structure of the limb is constructed by establishing its structural constraint system,and then several feasible axial/radial telescopic tire building drum schemes are ob-tained. This paper presents a new perspective for the innovative design of this kind of tire building drum,and also provides reference for the mobility analysis of spatial mechanisms with complicated structure,multi-ring couplingand multi-over constraint.