THEORETICAL ANALISYS OF THE MAIN INDICATORS OF HYDROMECHANICAL TRANSMISSION OF A TRUCK WITH WORKING SIZE VARIATIONS

Abstract

In connection with the growing trend of using continuously variable hydro volume-mechanical transmissions (HVMT) on vehicles, not only for agricultural purposes, but also for road-building, logging and special-purpose vehicles, the issue of installing this type of transmission on a domestic KrAZ vehicle is becoming more acute and promising.The most important part of the continuously variable HVMT is the hydrostatic transmission (HT), which provides a smooth change in the transmission ratio and consists of two positive displacement hydraulic machines: a hydraulic pump and a hydraulic motor. Determination of HT indicators when using hydraulic machines with different displacement volumes is a mandatory step, without which further work in the direction of using continuously variable HVMTs on special-purpose trucks is impossible.The article deals with the theoretical determination of HVMT indicators when using axial piston hydraulic machines of different working volume with an inclined disk in the HT. The influence of changes in the working volume on the main indicators of continuously variable HVMT is investigated, such as the efficiency (efficiency) of the HT and HVMT as a whole, the operating pressure drop, the engine power when driving in full-flow, in working and transport modes.As an object of research, we used a two-line HVMT No. 1, developed by the Department of Automobile and Tractor Engineering of the National Technical University "Kharkov Polytechnic Institute", a KrAZ 6233M automobile and axial piston hydraulic machines with a working volume of 89 cm3, 118 cm3 produced by the joint-stock company Gidrosila and 150 cm3 produced by the Italian company Bondioli & Pavesi. Recommendations on a possible stepless HVMT for the KrAZ 6233M vehicle are presented.