No abstract

Efficiency is considered, features of constructions and dynamics of motion of three-unit lorry convoys long 25.25м, that already used in a number of countries of ЄС on internal transportations and is actual for Ukraine, first of all in an agrarian sector and herd trade. In the program «Euro Combi» a «hook-loop» and biaxial trailers do not absolutely appear coupling devices as with the turning, guided axis, that yet until now present person in Ukraine from times of the USSR. The last are characterized by worst firmness of motion, moreover in composition a three-unit lorry convoy, in comparing to the modern construction of trailers with the fixed connivent axes and practically in the program « Euro Combi і» not examined. It is lifted question and corresponding updating of national normative base, that would allow to bring down the prime price of transportations and work-load of motorways. Keywords: lorry convoy, layout charts, firmness, dirigibility, dynamics of coupling devices, efficiency.

No abstract

In any economy there is a need for the bulky goods transportation which cannot be divided into smaller parts. Such cargoes include building structures, elements of industrial equipment, tracked or wheeled construction and agricultural machinery, heavy armored military vehicles. In any case, tractor-semitrailer should provide fast delivery of goods with minimal fuel consumption. In order to guarantee the goods delivery, tractor-semitrailers must be able to overcome the existing roads broken grade and be capable to tow a semi-trailer in off-road conditions. These properties are especially important for military equipment transportation. The important factor that determines a tractor-semitrailer mobility is its gradeability. The purpose of this work is to improve a tractor-semitrailer mobility with tractor units manufactured at PJSC “AutoKrAZ” by increasing the tractor-semitrailer gradeability. The customer requirements for a new tractor are determined by the maximizing the grade to 18°. The analysis of the characteristics of modern tractor-semitrailers for heavy haulage has shown that the highest rate of this grade is 16.7°. The factors determining the limiting gradeability value were analyzed, based on the tractor-semitrailer with a KrAZ-6510TE tractor and a semi-trailer with a full weight of 80 t. It has been developed a mathematical model to investigate the tractor and semi-trailer axles vertical reactions distribution on the tractor-semitrailer friction performances. The mathematical model has allowed to calculate the gradeability value that the tractor-semitrailer can overcome in case of wheels and road surface friction value and the tractive force magnitude from the engine. The mathematical model adequacy was confirmed by comparing the calculations results with the data of factory tests. The analysis showed that on a dry road the KrAZ-6510TE tractor with a 80 t gross weight semitrailer is capable to climb a gradient of 14,35 ° with its coupling mass full use condition. The engine's maximum torque allows the tractor-semitrailer to overcome a gradient of 10.45° It has been determined the ways to improve the design of the KrAZ-6510TE tractor to increase its gradeability. Keywords: tractor, tractor-semitrailer vehicle mobility, tractor-semitrailer vehicle gradeability.