ИССЛЕДОВАНИЕ ВЛИЯНИЯ РАЗБРОСА ДЕЙСТВИТЕЛЬНЫХ РАЗМЕРОВ ЗВЕНЬЕВ НА ПЕРЕДАТОЧНУЮ ФУНКЦИЮ МЕХАНИЗМА СКАЛОЧНОЙ ПОЛУАВТОМАТИКИ

Abstract

In this work, the analysis of real deviations from the nominal dimensions links, and their cumulative effect on the final movement of the chain linkage element rolling semiautomatic mechanism. The considered mechanism was converted to an equivalent one, consisting of lower translational and rotational kinematic pairs. In the course of the structural analysis, the mechanism was divided into Assur groups in order to simplify further kinematic calculations. The calculation was carried out sequentially for each of the structural groups separately. Based on this, a mathematical model of the kinematics of a rolling semiautomatic mechanism was developed, taking into account the real size of the links, that is, possible deviations of the links size from the nominal values for any combination of them. Using a specific example with the given installation dimensions of the mechanism, the transfer function of the output link (wedge) is built, and the range of its possible change is determined according to the specified dimensional tolerances. Combinations of link sizes for the boundaries of the range of change of the transfer function have been determined It is shown that with the tolerances indicated in accordance with the Unified system of tolerances and fits, the deviation of the position of the output link at the extreme position of the input link (pusher) can reach ±10 of that calculated by the nominal dimensions. This model can be used to solve the problems of optimal selection of tolerances and reduce the cost of manufacturing a product, based on the kinematic restrictions imposed on the functionality of the mechanism. The proposed approach to the construction and analysis of analytical mathematical models can be relevant for a wide variety of industries: machine tool building, engine building, weapons industry and aircraft building, especially where mechanisms are used that form long kinematic chains.