Hydrostatic steering is widespread in the construction of modern tractors. In recent years, it began to apply in designs of haulage trucks and high-speed crawler vehicles. This steering allows for the free arrangement of its main units, simplifies the design, reduces the material consumption of the machine and improves the working conditions of the driver. At the same time, the cost of manufacturing a hydrostatic power steering in recent years has significantly decreased due to the development of high technologies for the manufacture of its units. Hydrostatic steering is a purely hydraulic transmission with flexible connecting pipelines (hoses) of relatively high pressure, less reliable in operation than mechanical tractions, this requires increased attention to the reliability and safety of its operation. For this reason, it is not recommended for use on vehicles with transport speeds above 50 ... 60 km / h. In the known scientific literature there are practically no publications on methods for designing and calculating hydrostatic steering. In the educational literature on tractors, published by professors of the Moscow Polytechnic University, information is given on the design and methods for designing and calculating hydrostatic steering. The task of designing and calculating such a steering is selecting the necessary parameters for the hydraulic cylinder, the metering pump and the power source (drive pump) for it. These units are produced serially, from which the hydrostatic steering is designed. The technique of design and calculation of single-circuit and dual-circuit hydrostatic steering is considered. Information is provided on the characteristics of gerotor type metering pumps of foreign and domestic production.

The authors present the experimental results proving that in the real exploitation of a vehicle or a tractor self-exciting oscillations do not occur in friction pairs of friction clutch. This refers to friction clutches with asbestos, asbestos-free polymer and sintered powder friction pads.

The results of studies of the influence of mismatch of front and rear wheels tracks of 4x2 and 4x4 vehicles on their supporting off-road ability. Evaluation of off-road ability was carried out using the results of experimental studies of cars, as well as the calculation method using a mathematical model of a car on deformable support surface. Value of mismatch is characterized by a coefficient of track mismatch.

The paper discusses temperature effect of tire tread on durability of dump trucks pneumatic tires. The results of studying the nature of heat buildup in pneumatic tires during operation are shown. Method of statistical processing of experimental data was used to obtain regression models of inves-tigated multifactor processes.

Dual-flow hydromechanical transmissions are becoming increasingly widespread in the designs of modern land transport and traction machines (tractors, automobiles and high-speed crawler vehicles). This happens mainly due to the desire to increase the efficiency of transmission, although the capabilities of dual-flow hydromechanical transmissions are broader. In order to select a dual-flow hydromechanical transmission scheme in relation to specific operating conditions, it is necessary to know the advantages and disadvantages of various schemes, their potential capabilities. The evaluation of the operation of each circuit can be made on the basis of their kinematic and force analysis. The article deals with 12 dual-flow schemes of hydromechanical transmission with a differential element in inlet and outlet with a mixed meshing of gears, the results of the power analysis are shown. For the estimated parameters of a double-flow hydromechanical transmission were taken: й - power ratio of a double- гмп flow hydromechanical transmission; ан - coefficient of loading of the pump wheel of the torque converter; ам -load factor of the mechanical branch of the closed transmission contour; аa - load factor of the solar gear of the three-link differential mechanism. For each of the schemes considered, analytical dependencies of the estimated parameters on the internal parameters of the hydromechanical transmission were obtained. For the parameters were used the characteristic k of planetary gear set, power йгт and kinematic игт gear ratios of torque converter. It is assumed that, at the boundaries of the range й = да and й = 0. Calculations have been performed to determine the parameters й , гмп гмп гмп ан , ам u аа for different values of k and й , results of which made possible to evaluate the potential transforming properties of the schemes of two-flow hydromechanical transmissions independently of the model of the used hydrotransformer.