Vliv styčné plochy pneumatik na tahové vlastnosti traktoru

Abstract

The paper presents a comparison of pulling properties of a prototype of three-axle tractor 6K6 with the classical tractor John Deere 8400. To compare differences in the contact surface of wheels the authors measured the area of tyres of tested tractors. It was found out that the contact surface of tyres of 6K6 tractor was larger by 62 % than that of John Deere 8400. Results of measurements performed on a stubble indicated that the drawbar pull force of 6K6 tractor was 70 kN while that of 4K4 only 58 kN (slippage of wheels was in both cases 40 %). It was concluded that although the weights of both tractors were comparable, a greater drawbar pull force of 6K6 tractor resulted from a larger contact area of tyres with soil surface. The maximum drawbar power of 6K6 tractor was measured at the speed ranging from 13 to 17 km.h-1. In case of John Deere 8400 tractor, the maximum drawbar power was recorded at speeds of 9 to 13 km.h-1.Wheels of the prototype 6K6 tractor were tyred with tyres 480/70 R 30. The equation of slippage curve was derived on the base of measured results and the coefficient of adhesion.