ASSESSMENT OF THE STABILITY OF THE FRONT PIVOT AXLE DURING STEADY-STATE MOTION OF A TRACTOR SELF-PROPELLED CHASSIS

In known scientific and technical literature, insufficient attention is paid to the study of dynamic processes of wheeled vehicles with a steering front axle. The use of front swivel axle on a self-propelled chassis makes it possible to minimize the moment of resistance to turning and reduce the wear of front wheel tires in comparison with rotary guide wheels. This modernization can provide a wider range of attachments for mechanized work equipment. The aim of this work is to increase the stability of the rectilinear steady-state motion of a self-propelled tractor chassis by creating stabilizing moments on the front pivot axle by shifting the axis of rotation of the front axle in the direction of the longitudinal axis of the machine. The stability of the rectilinear steady-state motion of a self-propelled tractor chassis is investigated when creating stabilizing moments on the front steering axle by shifting the vertical axis of rotation of the front axle in the direction of the longitudinal axis of the machine. This scientific article shows that when the steering axle moves, it is possible to reduce the lateral force on the front axle to zero, which makes it possible to reduce the moment of resistance to turning. A straight-line steady-state movement of a tractor is considered, where a violation of the stability of the front steering axle may occur during a short-term impact on an obstacle on the road.  In some cases, the angular acceleration and angular velocity of the bridge in the road plane may be the exciting factor. The loading scheme of a front swing bridge under the action of an exciting angular acceleration is determined.  The calculation of the effect of the exciting factors on the power steering cylinder is presented. The stabilizing moment that occurs when the axis of the vertical shaft of the front steering axle drive is displaced is determined. The differential equation of the front axle's circular motion was analyzed, which revealed its stability under the action of short-term excitatory forces in the rectilinear steady-state motion of the self-propelled chassis. An estimation of the motion of the front steering axle of a self-propelled chassis is presented, with the determined proportionality coefficients and coefficients of the differential equation, which describes the stable motion of the front steering axle in the steady-state rectilinear motion of the machine under the action of short-term disturbing forces. Keywords: self-propelled chassis, front swivel axle, stability, stabilizing moment, steady-state motion