Traction properties of tires of size 33-32 with different inner structures

The purpose of the research: to determine the traction and energy properties for the large-sized low-pressure tires of size 33-32 with different internal structure, intended for the undercarriage systems of class 5 tractors. The research method is expe-rimental and with the use of the «tire tester» measuring complex. From the main provisions of the theory of a tractor and experience of tire testing, it is known that the total traction efficiency of a tractor, as a generalized index of its efficiency, is almost completely determined by the value of the efficiency of its undercarriage. The output indices of the propulsion of the undercarriage systems in powerful tractors with a pneumatic tire are determined by a number of factors, including the reinforcing parameters of their internal structure. The calculation of traction energy and transient processes using the example of units with class 5 tractors showed that losses can be reduced and, therefore, the output indices of units can be increased if the longitudinal stiffness of the tractor tires is increased and the load is combined, at which the tires have the maximum of traction efficiency with load, that determines the traction class of a tractor. The test results of the compared tires showed: the level of indices of the tested models on a concrete support base is practically the same, except for the 33R-32M tires and, in particular, the 33DP-32 tires, which have the best traction efficiency and slippage coefficient, which is determined by its increased longitudinal and circumferential stiffness, which is a criterion for the design of a tire shell of this type; on the winter wheat stubble and field prepared for sowing, the traction efficiency value of the 33R-32M and 33DP-32 tires is for 0,03 more, and the slippage is for 5-16% less than in the serial tires, and this advantage is especially evident at a low intra-tire air pressure (for the 33R-32M tire, this is observed at a pressure of 0,09 MPa per pair and 0,11 MPa on the stubble of spiked cereals; for the 33DP-32 tire - 0,07 MPa per pair and 0,09 MPa on the stubble of spiked cereals).