The influence of the properties of materials used to make the working bodies of the stripper header on the quality of the performed process

Abstract

The aim of the inveatigations is to develop the main provisions of the procedure for determining the influence of material properties on the example of steel and ultra-high molecular weight polyethylene (UHMW PE) when they are used to fabricate or cover the outer and inner surfaces of the fairing and the combing teeth of the header, on the quality of the process performed by it. The dependencies and regularities that are integral parts of the previously developed mathematical model of the process of combing grain crops with a single-barrel header are used in the article. As a result of solving the equations, data on the normal and tangential components of the speed of movement of the ear and grain after contact with the test surfaces were obtained. Upon contact with the external surface of the fairing that material would be preferred which the movement along is accompanied by a lower value of the frictional force. During a rebound from the combing tooth and the inner surface of the fairing, the best material is the speed of rebound of the grain from which is higher. The value of the normal forces pressing the ear of winter wheat to the contacting surface was determined in an experimental plant simulating the process of combing the reaper. The coefficient of static friction and motion and the coefficient of recovery upon contact with the surfaces of steel and UHMW PE ears and winter wheat’s grains were determined at its moisture content of 9 %. It has been established that at a header speed of 3 m/s, the frictional force pressing the ear to the outer surface of the fairing from UHMW PE is 1,75 times less than on the steel. After contact with the tooth, the rebound speed of the grain is higher, if it is made of steel. For the accepted characteristics of the harvested plants and the operating conditions of the header, when the grains come into contact with the inner surface of the fairing from the UHMW PE within the friction angle, the loss of grain velocity after the collision is less than on the steel, with the exception of contact with direct impact. Compensation for the reduction in speed within a direct impact on the inner surface of the fairing which is made of UHMW PE can be achieved by varying the angle of inclination of the combing teeth on the drum.