MECHANICAL ELEMENTS: DIMENSIONAL ANALYSIS OF THE FITS

In the mechanical elements production, when a piece is manufactured, the specifications are available, which can be dimensional, strength, weight or any other. The obtained product is accepted when it is within a tolerance margin, which means that it will not have an exact measurement as predicted. To achieve interchangeability, it is just necessary to rely on dimensional tolerance. It is classified for each type of work and the corresponding one is assigned in each case, according to the working conditions or the purpose of the work. It is taken into account that the fit consists in the dimensional union of two pieces and it is determined by the difference between their dimensions, given by their respective tolerances intervals, before their assembly; that is, by the fits' magnitude obtained in the union. This research work has carried out a dimensional analysis of the adjustment of three couplings, belonging to the speed box of a UAZ 469 Jeep, to the feeding system of a matches manufacturing machine and to a Yung-6 tractor. The authors have identified the main problems during the manufacturing of the different machine elements; that lead to economic losses for the enterprise and for the country.