Analytical justification of the load capacity of pneumatic tires for tractors and agricultural machinery

Abstract

Information on the parameters and operating modes of pneumatic tires for tractors and agricultural machinery is contained in state standards in the form of tables in digital form. The variety of types, sizes and designs of tires makes it difficult to determine the tire parameters taking into account conditions and operating modes. The information on the tire parameters is insufficient due to the lack of information about the contact area of the tire with a solid support surface. The article suggests the dependences of the load-carrying capacity of a tire on the generalized geometric parameter equal to the product of the outer diameter and width of the tire profile. The area of contact is an important parameter that affects the traction characteristics of the tractor, the depth of the track when driving on a plowed field and the resistance to movement of the tractor. New terms have been introduced - the theoretical and actual contact areas of the pneumatic tire. The dependence of the theoretical contact area on the generalized parameter equal to the product of the outer diameter and width of the tire profile for diagonal and radial tires is obtained. The cross-section method is used, by means of which the bus contact is cut off from the shell. In this case, the internal forces of the pneumatic tire framework are transformed into real external forces. The analytical dependence of the load capacity of a pneumatic tire is obtained, representing the algebraic sum of the lifting force of the shell and the vertical force of the frame. The universal formula is proposed for determining the actual contour area of the tire contact, in which the contact length and width are used. The values of the length and width of the contact, as well as the ratio of these quantities, are determined experimentally for different loads and pressures, the contact length being determined by the proposed analytical method.