Patent RU-2727314-C1 (RU)
Title: Aircraft turbojet engine fan rotor with long wide-chord hollow blades with dampers
Inventor: ESKIN IZOLD DAVIDOVICH
IPC: F04D29/38
Filed: 2019-10-04
Granted: 2020-07-21
Abstract: FIELD: aviation.SUBSTANCE: disclosed is an aircraft turbojet engine rotor comprising a sleeve with flanges for attachment of the spinner and support stages rotor drum, a back spinner fixed on the bushing, front spinner mounted on rear spinner, long saber-like wide-chilled hollow blades, fixed in slots of bush rim with dovetail locks, friction elements and elastic hysteresis element. In the rear spinner flange, fixed on the bushing with cut heads, washers and self-locking nuts, on the diameter larger than the diameter, on which the bolt holes are located, there is an annular groove concentric to the rotor axes, with conical support surfaces, wherein generatrixes of said surfaces are parallel and vertexes of cones are located opposite flight and lie on engine longitudinal axis. In external flange of this groove there are through slots with vertex, made along arc of circle, which is tangent to lateral sides of slot, and radially located in response to blades of fan impeller. Elastic hysteresis element is inserted into annular groove with tension along its shelves and made in the form of annular multi-span corrugated pack of corrugations in corrugation from one, two, three and more cold-worked or crushed polished corrugated tapes from stainless steel. In their slots with their bases without a gap or with a very small gap along groove walls, preferably with a gap less than 0.02 mm, friction elements are inserted to the stop by bases in the elastic-hysteresis element. Friction element is pressed by elastic force created by elastic deformation of corrugated pack corrugation, and centrifugal force created by weight of friction element, by upper end and lateral side - by surfaces of its power elements to contacting with them mating surfaces of blade strength elements. Friction element is made hollow, and the height of the friction element is selected so that its upper end face and the mating side of the wing of the wide-chilled blade contacting with it are located outside the units of dangerous oscillation modes of the blade at the place of high amplitudes of its blade displacements. Outer surface of rear spinner, located between bases of friction elements, surfaces of their bases, which are as if extension of these surfaces and connecting them with surfaces of friction elements feathers, are made flush with mating surfaces of the bushing located between locks of blades, surfaces of locks of blades and feathers of blades and an inter-blade gas channel is organized together with these surfaces. Rigidity of friction element is not less than value of one order with rigidity of hollow blade, and selected so that on contact surfaces of friction element in all dangerous modes of oscillating blades tangential stresses overcome specific forces of dry friction and there is elastic mutual slip with dry friction on contact surfaces of friction element and oscillations of long hollow fan blades are effectively damped in all working modes of the engine, and corrugations of the elastic hysteretic element are elastically cyclically deformed.EFFECT: improved efficiency of vibration and impact loads control.1 cl, 10 dwg