Multiple-axle steering system for agricultural harvesting machines

Abstract

A multiple-axle steering system for an agricultural machine with at least one primary-controlled axle and at least one secondary axle, where the latter's steering deflection angle varies along a progressive characteristic curve as a function of the primary-controlled axle's steering deflection angle. The variation in steering deflection angle along the progressive characteristic curve means that the steering deflection angle of the primary-controlled axle in a range around the zero or neutral position initially results in only a slight steering deflection of the secondary axle. As the steering deflection of the primary-controlled axle increases, the steering deflection angle of the secondary axle progressively approaches the steering deflection angle of the primary-controlled axle. When using all-wheel steering, the use of the progressive characteristic curve facilitates smooth steering when driving on the road, where usually minimal steering deflection is performed by the machine operator. Maneuverability is achieved because an increase in the steering deflection of the primary-controlled axle causes a correspondingly greater ratio of steering deflection of the secondary axle. Furthermore the progressive characteristic curve for all the steering modes provides a standard steering strategy for use of all-wheel steering in combination with special types of synchronous steering.