New safety device for the driving system of forest tillage machines

The paper substantiates the operability of a new cam-type safety device due to the results of experimental studies of a safety device function installed in a cardan drive of a tillage machine. A new two-cam safety unit with an elastic rubber element was studied in the course of a full-factor experiment taking into account the dynamic parameters of the system. The advantages of the proposed safety unit design are revealed. The authors obtained a regression model of the safety device parameters influence on the dynamic loading. The model allows designing forest complex machines with safety devices installed in the drive units and determining the influence of the subshaft inclination and the moment of inertia of the system taking into account their rotational speeds. It is revealed that an increase of such variable factors values as rotation speed, the angle of inclination of the subshaft and the moment of inertia of the system results in dynamic loading increase. The frequency of rotation exerts the most significant effect on the value of the maximum dynamic loading while the moment of inertia has less effect and the angle of inclination exerts the least one. To minimize the values of dynamic loading the angle of inclination of the subshaft should be in the range from 0 to 15 degrees, taking into account the values of the moments of inertia of the rotating drive elements on which the safety unit is installed, also in the range of values from 0.012 - 0.024 Nm. The optimal values of the rotation speed and the angle of inclination of the subshaft are determined thus ensuring minimal dynamic loading. The research results may be effectively used in the further development of forest complex machines taking into account the designs of safety devices and their dynamic loading.