The Power Load on Kinematic Pairs of Tractor Variable Base Mechanism

Abstract

Both longitudinal and transverse stability as well as maneuverability and controllability are important parameters of the tractor for efficient processing of land areas in mountainous and foothill areas, which surface has significant irregularities, and are often located under large bias. It is known that in order to ensure the stability of the tractor, its base must be maximum, and to ensure a minimum turning radius – minimum. However, the design used in the agro-industrial complex of the Republic of Uzbekistan 4-wheel universal tractors does not provide a mechanism for changing the wheelbase. In this regard, SDB Tractor designed 4-wheeled universal tractor, equipped with a special mechanism that changes the base of the tractor by 670 mm. It is showed that the reliability of the mechanism depends primarily on the strength of the parts, which account for the maximum power load. (Purpose of the study) We investigate the force loads acting in kinematic pairs of the alternation mechanism of the tractor base. (Materials and methods) The possibility of changing the parameters of the tractor base is showed on the example of the 3D model. To calculate the parameters of the designed tractor came from the figures: weight per axle; the dimensions of the hinge parallelogram arrangement; the radius at which the moving end of the rod of the hydraulic cylinder; a rolling resistance of the front wheels on the supporting surface of the concrete cover, etc. (Results and discussion) Power loads in kinematic pairs of the tractor base change mechanism were determined on the basis of generally accepted methods of the theory of mechanisms and machines with the use of structural analysis of the mechanism. The magnitude of the forces acting at each kinematic pair of mechanism for database changes, calculated by the graphical-analytical method on the basis of the law of statics using conditions of equilibrium. (Conclusions) It is found that the values of forces acting in the hinges of the mechanism of changing the base of the tractor range from 8816.25 H to 93255.82 H. On the basis of the calculations presented the following results: the greatest efforts in the links of the mechanism of change of the tractor base act in their longitudinal direction, which should be taken into account when one determines the parameters of the mechanism of change of the tractor base and the calculations of parts for strength.