The optimization of parameters of a safety element of the finger mechanism of the header auger of a combine harvester

Abstract

BACKGROUND:One of the most frequently recorded failures of structural elements of the header auger of a combine harvester is the failure of the fingers of the finger mechanism. Many manufacturers of grain harvesting equipment introduce a safety element into the design of the finger mechanism which is a groove on the finger. The optimal location of this groove with relation to the axis of rotation of the pin allows to ensure the breakage of the auger finger not along the main diameter but along the groove at a certain section of the working stroke of the mechanism.
 AIMS:In the specific technical literature, no special attention is paid to the analytical calculations of the structural elements of the finger mechanism of the header auger that requires the development of appropriate mathematical models depending on the targets.
 METHODS:This paper presents a mathematical model of the finger mechanism of the header auger of a combine harvester, based on the use of vector analysis, which has been successfully used by the author for a long time in the development of various lever mechanisms. The proposed vector analysis method is based on the coordinate transformation method.
 RESULTS:The mathematical model of the finger mechanism of the auger presented in the article made it possible to describe the kinematics of all of its hardpoints, to determine the vectors of angular velocities and accelerations of the links, to carry out a force analysis with optimization of the position of the safety element on the finger as well as to obtain and to study various graphical dependencies. The developed mathematical model provides a comprehensive description of the kinematic and force parameters of the considered mechanism for all of its positions.
 CONCLUSIONS:The presented mathematical model of the finger mechanism made it possible to successfully optimize the parameters of the location of the safety element on the finger - the groove, thereby ensuring the maximum angle of coverage of the zone of possible breakage of the finger along the groove.