用机构扩展法确定速度瞬心的方法

The Way of Locating Velocity Instantaneous Center with Extending Mechanism Method

用速度瞬心法对机构进行速度分析首先必须确定两构件之间的速度瞬心。对于某些简单机构,有时单凭所分析的机构中构件之间的关系却不能确定两构件之间的速度瞬心。为了解决这类问题,提出了机构扩展法用于解决不定速度瞬心的问题。机构扩展法就是将原机构进行扩展,机构中的构件数增加,能够用于三心定理的三构件组合数增多;同时,保证扩展后的机构与原机构等效,由扩展后的机构确定原机构中两构件之间不能确定的速度瞬心的方法。本文通过实例分析,介绍了这种方法的应用,为机构的运动综合提供了一种新的方法。

The instantaneous center of velocity between two components must first be located in order to analyze the velocity of the mechanism using the velocity instantaneous center method. For some simple mechanism, the velocity instantaneous center between two components can not be determined by the relations between components in analy- zing mechanism. In order to solve the kind of problem, this paper puts forward the mechanism extension method to determine some indefinite instantaneous center of velocity. The mechanism extension method is the way that the ini- tial mechanism is extended to the mechanism consisting of more components and it increases three component com- binations being used for theorem of three velocity instantaneous centers. Meanwhile, it is ensured that both the ex- tended mechanism and the initial mechanism are equivalent. Thus, some indefinite instantaneous centers of velocity in the initial mechanism can be located with its extended mechanism. The application of the mechanism extension method is demonstrated with examples and the results show that the new method is supplied for the kinetic synthesis of mechanism.