ANALYSIS OF THE INFLUENCE OF TRAFFIC MODESOF THE TRACTOR WITH A SEMI-TRAILER FOR THE LOAD OF THE FITCH DEVICE

The article presents the advantages of timber tractors with semi-trailers in comparison with single timber vehicles. The existing road condi-tions for the operation of saddle road trains in-volved in the transportation of timber to con-sumers are described. The causes and conse-quences of loading elements of saddle-coupling devices of road trains are considered. The de-pendences of the change in forces in the cou-pling device on the values of the coefficients of adhesion and the distribution of braking forces, the deceleration of the saddle road train, and also on the height of the center of gravity of the semi-trailer of the road train are presented. The regularities of changing the braking distance, deceleration and compression force in the fifth wheel coupling device of a road train due to un-derutilization of the coupling weight of a tractor with a semi-trailer are considered. The depend-ences of changes in loads in the fifth wheel cou-pling on road conditions, the load of the road train, the location of the fifth wheel coupling on the tractor, as well as on the damping coefficient are analyzed. An analysis of oscillograms of changes in forces in the pivot of the device in the process of sharp braking on a curvilinear and rectilinear trajectory with various options for braking by individual links is given. The influ-ence of the road train load, the speed of its movement, the type of road surface, the design parameters of the coupling device, the presence of lubricant on the base plate, the level of its wear on the change in the moment of resistance in such a device are described. The necessity of increasing the efficiency of timber tractors with semi-trailers by improving the existing designs of fifth wheel couplings is substantiated.