Dual steering system for off-highway vehicles - uses electric motor powered from vehicle battery to drive secondary hydraulic pump

摘要

A dual vehicular steering system has a primary system for normal operation and a secondary system for emergency operation triggered by pressure sensitive switching and valving devices. Both systems have in common a pair of single rod hydraulic steering cylinders with each cylinder being connected to a steerable wheel of the vehicle, a vehicular engine and hydraulic fluid stored in a tank. Cylinder shuttle valves are connected to each steering cylinder function as gate devices to separate the primary steering system rom the secondary system. The primary system includes a main pump driven by the engine, a high pressure filter, a priority flow divider to divert fluid in excess of an acceptable flow level, a control valve, an integrated valve package to proportionately regulate fluid flow between the cylinders, and lines to direct fluid from the tank to the pump.