THE ESSENCE OF METHODS FOR CALCULATING DIMENSIONAL CHAINS IN DESIGNING DETAILS OF AGRICULTURAL MACHINERY

Abstract

The quality of machine and mechanism performance largely depends on the quality of manufacturing of parts and the assembly process. The assembly process, both after the direct production of components and after their restoration during repair, is based on the development of design and technological documentation, an essential element of which is the calculation of dimensional chains. The existing interstate, national, and industry regulatory documents define the procedure and rules for calculating dimensional chains. In Ukraine, when developing a technological assembly process at the design stage, interstate standards such as GOST 16319-80 and GOST 16320-80 are used. During the assembly stage, technological and design solutions are applied to achieve the required dimensional accuracy, which often leads to additional technological operations and costs. However, it is possible to reduce the total assembly error and the number of technological operations already at the design stage (Cherkashyna, 2013). GOST 16320-80 establishes methods for calculating dimensional chains using various approaches to achieve the accuracy of the closing link, in particular: the method of complete interchangeability, the method of partial interchangeability (probabilistic method), the method of group interchangeability (selective assembly), the fitting method, and the adjustment method. This article discusses the essence of calculating dimensional chains using the methods of partial and group interchangeability in the manufacture of agricultural machinery parts.