초록 ▼

A tracked vehicle has an electrohydraulic drive/steering system having an engine driven variable displacement hydraulic steering pump which drives a hydraulic steering motor which is coupled to a differential track drive mechanism via a transmission with multiple gear ratios. A steering wheel is cou

A tracked vehicle has an electrohydraulic drive/steering system having an engine driven variable displacement hydraulic steering pump which drives a hydraulic steering motor which is coupled to a differential track drive mechanism via a transmission with multiple gear ratios. A steering wheel is coupled to a variable friction device which produces a variable friction force which resists rotation of the steering wheel. A control system is responsive to a position of the steering wheel and controls the steering pump displacement and controls the friction device. The control system sets the variable friction device to its high friction level when a limit of the steering pump displacement is reached when the transmission is in a higher one of its gear ratios.

대표청구항 ▼

1. In a control system for a tracked vehicle drive/steering system, the tracked vehicle drive/steering system having an engine driven hydraulic steering pump which drives a hydraulic steering motor which is coupled to a differential track drive mechanism, the steering pump being responsive to a posi

1. In a control system for a tracked vehicle drive/steering system, the tracked vehicle drive/steering system having an engine driven hydraulic steering pump which drives a hydraulic steering motor which is coupled to a differential track drive mechanism, the steering pump being responsive to a position of a steering wheel, the steering wheel being coupled to a variable friction device which produces a variable friction force which resists rotation of the steering wheel, the improvement wherein the control system comprises:an engine speed sensor which generates an engine speed signal; a ratio generator for generating a ratio value representing a ratio of the engine speed to a desired steering motor position increment value; and a comparator for comparing the ratio value to a limit value, and for controlling the variable friction device as a function of a relationship between the ratio value and said limit.