THE CALCULATION OF THE DEPENDENT TOLERANCE ALIGNMENT REPAIR SHAFTS GEAR BOXES
Traktory i sel'hozmashiny
Distortion of the shape of the component parts leads to a decrease in the operational properties of these parts Thus, in movable joints the deviation of the component parts from the correct cylindrical shape leads to an inadequacy of its movements, rapid wear due to contact over a limited surface. In fixed joints, distortion of the shape leads to uneven tension in the joints, because of this, the strength of the joint, the tightness and the accuracy of the centering decrease. Distortion form
... o affects labor and assembly accuracy, increases the amount of trimming work affects the accuracy of basing of parts in the manufacture and control. Deviations in the location of surfaces from their nominal values are extremely detrimental to the reliability of the machines, causing additional static and dynamic loads in separate parts and joints, which leads to rapid wear and fatigue failure of the parts. Tolerances location or shape to be set for shafts or openings may be independent and dependent. Dependent location tolerances are set for the items, which are interfaced with the object at the same time on two or more surfaces, and for which the interchangeability requirements are reduced to ensure the collection, ie, connectivity details on all mating surfaces. Dependent tolerance indicated in the drawing or other technical documents value which may be greater than the value of which depends on the deviation of the actual size of the element and / or the base material of the maximum limit. On the example of the shaft of the unified reducer of the MOSSELMASH plant, under the designation H090.040, three variants of the assignment of the dependent tolerance of alignment are considered, which, on the one hand, allows to expand the capabilities of the technological equipment and reduce the cost of processing, and on the other hand, ensure the assembly of connections without fitting. For our example, the use of the third variant of the notation extends the alignment tolerance of the two shaft surfaces from 0.010 to 0.048 mm, which is not only economically feasible, but also allows the use of full interchangeability to be competently used.