Emergency lubricating device for a reduction unit particularly for a main gear box of a rotary-wing aircraft

Claim 1

Emergency lubricating device for a gear reduction unit and more particularly for a main gearbox of a rotary-wing aircraft in which a normal lubricating circuit, fed by at least one pump, distributes oil from a normal reservoir under pressure through nozzles in a direction of elements of the gear reduction unit, said emergency lubricating device comprising: at least one branch duct branching from the normal lubricating circuit; a special emergency lubrication circuit; and at least one emergency reservoir fed by oil from said at least one branch duct to maintain a predetermined level of oil during normal operation and having an overflow connected to the normal reservoir, said at least one emergency reservoir continuously distributing the oil maintained therein through said special emergency lubrication circuit to critical elements of the gear reduction unit at a low rate prior to returning the oil to the normal reservoir, wherein a minimum lubrication of said critical elements is provided for a time sufficient to reach a landing ground during a complete failure of the normal lubricating circuit.