Theoretical Investigation of Selection (Calculation) of Design Parameters of Modular Draft Device in Aggregation of Semitrailers

One of the directions for expanding the functional properties of modular draft devices (MDD) is their use with semitrailers (using a fifth-wheel coupling, installed on the technological module). The issue with this is due to their ability to create such a redistribution of the MDD operational mass along the semitrailer’s axles whereby the loss of control of the entire transport aggregate is possible. To solve this problem, regularities have been established to consider in choosing the design parameters of the MDD. It has been established by theoretical calculations that an increase in the angle of inclination of the central α, with negative values of the angle of inclination of the lower β links of the rear-mounted mechanism of the MDD’s power module (PM), leads to an increase in the vertical load of the wheels of its technological module. The transition of the longitudinal coordinate point of the semitrailer’s tractive resistance application from −0.30 m to +0.30 m, provided α > β, leads to an increase in the vertical load on the wheels of its technological module. Increasing the angles of inclination of the central and lower links of the rear linkage of the PM leads to an increase in the vertical load on the wheels of its front axle. An exception is the option in which the lower links of the specified linkage mechanism are set at a negative angle at the level of −10°. An increase in the value of the angle of inclination of the central value, with positive values of the angle of inclination of the lower links of the rear-mounted mechanism of the PM, and compliance with the condition α < β, leads to a decrease in the vertical load of the wheels of the technological module.