RESEARCHES ON THE DIMENSIONAL SYNTHESIS OF THE THREE-POINT HITCH COUPLERS USED AT AGRICULTURAL TRACTORS

Abstract

The paper presents the analytical method applied to outline the dimensional synthesis of the three-point hitch couplers used at agricultural tractors. The dimensional synthesis is framed with the specific aim of determining the basic dimensions of all the elements of the three-point hitch couplers considering the kinematic properties (positions, speeds) imposed by both technological processes and agro-technical conditions. The mechanism is divided in three kinematic groups. The study and the mathematical modeling is carried out for each distinct group taking into account the piston position in the lift cylinder of the three-point hitch couplers. The coordinates of each hitch point (to both rear axle and ground), the position and the instantaneous center of revolution are further determined. This mathematical modeling lies at the basis of the analysis into the kinematics and dynamics of the three-point hitch couplers used at agricultural tractors. The paper shows the results of the researches conducted on wheeled tractors U 650 and U 650 DT.