The thesis is devoted to solving the actual scientific and applied problem of increasing the efficiency of motor-grader at the expense of reducing the load of working equipment. The thesis is devoted to solving the actual scientific and applied problem of increasing the efficiency of working equipment (on the example of middle class motor graders). It is achieved by stabilizing the load mode of the traction frame suspension mechanism (TFSM) by modernizing the working equipment with an additional suspension element. It will improve the machine efficiency by reducing the asymmetry load of hydraulic cylinders of motor grader working equipment, and, as a result, increase the machine’s working life at operation. In the thesis the relevance of the topic is substantiated, the object, subject, purpose and objectives of the study are formulated, the research methods are described, and the thesis connection with scientific programs, plans, topics are determined. Information on approbation and publication of the results of the thesis research is provided, the literature search and its analysis is made, appropriate static and dynamic models are developed; field experiments were carried out in field conditions with the existing TFSM, a virtual model of the working equipment was generated and the kinematics of the existing and modernized equipment were analyzed, practical recommendations for the rational choice of design parameters for the TFSM were developed and economic efficiency of the proposed method of increasing the durability of graders was calculated. The scientific novelty of the results is the following: using the developed static spatial scheme and mathematical model, the dependencies of the forces in the actuating cylinders on the input kinematic characteristics and external power loads were determined taking into account the specific features of the TFSM design; using the developed dynamic spatial scheme and mathematical model, the dependencies of the efforts on the grader blade on the external input loads were determined taking into account the asymmetry of the TFSM design; the level of efforts asymmetry in the TFSM hydraulic cylinder during operations was established; new regularities of the variable coordinates location of the TFSM hydraulic cylinders and modes of the working process to the TFSM hydraulic cylinders’ load have been established. The results of the research were implemented in the LLC «Mashhidropryvid», LLC «Kharkivspetsbud-1», the design and installation firm LLC «Specialized Management of Mechanized Works», and in the educational process for bachelors in specialty 133 «Mechanical Engineering» in Kharkiv National Automobile and Highway University. The mathematical model is improved for static and dynamic loading with respect to their use for all types of motor graders, taking into account kinematic dependences of TFSM, which guarantees the accuracy of calculations with a relative error within acceptable limits (confidence interval 0,9) and increase of machine efficiency of about 25%. For the first time, the influence of the location of the point of application of external loads on the main blade to the load of TFSM was experimentally investigated, which indicates the inaccuracy of the use of previously existing calculation methods. On the basis of additional tasks, an engineering method was developed to determine the rational parameters of the working equipment load, which allowed us to offer a modernized design of the mechanism for securing the hydraulic cylinder to pull the traction frame to the side, which results in reducing the uneven loading of the TFSM actuating hydraulic cylinders, which, in turn, leads to the increase of durability and performance of motor graders. The influence of the displacement of external load application point along the cutting edge of the main blade has been analyzed, not only the change of force in the hydraulic cylinders of the TFSM motor grader has been established in absolute value, but also the change in the direction of the existing reactions. A computer model of the upgraded motor graders TFSM has been developed, that allowed for the results of virtual research to offer the method of changing the kinematics of traction frame suspension, which ensures reduced load at motor-grader operation. The implementation of the results of the studies performed on the motor graders with modernized working equipment in the form of an additional mechanism for the suspension of the traction frame will increase the durability of the TFSM and the motor grader, as a whole, which will increase the machine’s efficiency and material costs. Eventually it will increase motor grader efficiency during operations.
