FIELD: aviation.
SUBSTANCE: group of inventions relates to aircraft turbojet fan blade length 700÷1,500 mm with vibration damping damper. Disclosed is a long hollow wide-chord fan of aircraft turbojet engine, containing two taper halves made of titanium alloy, each consisting of integral shells with locking part with lock "dovetail" and end part and power bearing elements – ribs located on part of blade length and connected to lock part and end part, and damping element or two damping elements. Vane halves along its middle surface – points of contact of ribs, locking and end parts of the blade halves – are rigidly connected to each other by diffusion splicing at temperature of 920–950 °C in vacuum, in die repeating geometrical shape of finished blade, under action of load pressing half of blade to each other. Damping element is made in the form of multilayer multi-span beam assembled of m ≥ 10 steel tempered polished tapes assembled in arrangement m = m1 + 2m2 + 2m3 + 2: in the center of the package there are m1 = 1, 2 and more smooth tapes, on both sides "corrugated peaks to corrugation peaks" two packages are installed, assembled "corrugation in corrugation" from m2 = 1, 2 and more corrugated tapes, on which are installed packages of m3 = 1, 2 and more smooth tapes, outside the package there are smooth tapes, one on each side of each packet, with thickness ho = (k/2)⋅h, where k = 2÷10 and h is thickness of inner tapes of damping element in mm, and in assembled damping element corrugated ribbons are elastically completely straightened. On the inner surface of each of the blade halves or in the middle part of the shell there is a rectangular projection or two such projections located at some distance from the blade edges, in which on length of damping element is made a rectangular slot with flat bottom, with depth equal to or greater than thickness of steel smooth band installed in this slot. In the lock of each half of the blade one or two cutouts are made, which are located in response to the ledge. In each rectangular slot of the projection of each half of the blade through the slot with a gap along the perimeter of the slot, which is selected at working temperatures of the blade, a smooth band is inserted and a damping element is inserted between each pair of these tapes with interference along its supports. All straps of the package and steel smooth bands on which it rests are made of steel hardened or cold-worked ground belts out of heat-resistant stainless steel, which does not lose elastic properties at temperature of 600 °C, and the contacting surfaces of said tapes are coated with a wear-resistant coating which retains its protective properties at that temperature. Damping element supports are made in the form of brackets made of aluminum alloy, ends of which are bent to package from side, where the supports rest on the smooth belt with plates made from a smooth steel rolled tape with a thickness equal to the gap between the support and the second smooth belt, and their bearing surfaces are coated with a wear-resistant material. Supports resting on one half of blade are installed on package or packages of both damping elements with pitch equal to two steps of crimps in rectified package, and are located so that middle plane of support passes through corrugation vertex, and supports resting on the other half of the blade are offset from these supports by the pitch of the corrugations in the straightened package. Position of each support together with the plate and bent ends of staples on the packet is additionally fixed by means of two rivets located on sides of the package in semicircular mopping in it. Support of damping element locking part is also made of aluminum alloy and with tension is put on package, and support itself is made with rectangular base and inclined to it lateral sides forming "dovetail", or sides without inclination, and its geometry accurately repeats cut geometry or each of two cutouts in lock and blade lock part, and damping element or two damping elements through cutout or cutouts are inserted inside blade body so that support of locking part of damping element by its sides without sides gaps rests on sides of cut and fixed on package also by two rivets arranged on sides of pack in semicircular milled out therein, or damping element is additionally fixed in blade lock by two pins, pressed into through holes in blade lock and support, also located in milling of pack. Disclosed is a method of making a long hollow chilled-wall fan of a turbojet engine, consisting in the fact that from the titanium alloy by stamping with subsequent finishing milling two halves of the blade are made in the form of integrated shells with lock and end parts and power elements – ribs connected to the shell and these parts of the blade halves, and jointing of two halves of blade on areas of contact of lock and end parts, parts of shell at edges and ribs under pressure, diffusion welding at 920÷950 °C in vacuum, in die repeating shape of finished blade, from steel toged or cold-worked ground belts from heat-resistant stainless steel, which does not lose elastic properties at temperature of 600 °C, smooth and corrugated tapes are made, coated with wear-resistant coating, preserving its protective properties at this temperature, and assembled of these tapes layout m = m1 + 2m2 + 2m3 + 2 with structural parameters of the assembling ribbons and the layout itself, selected so that with the selected method of bending the ends of staples on a package, optimum UV characteristics and strength of the blade are provided, and the package in all operating conditions of the engine is deformed elastically or plastic deformations occur in cross-sections of the tape of the package occupying allowable areas and did not break the strength of the package. Assembled assembly is fitted with the first bracket in accordance with the selected method of bending the bracket ends. Bend its ends, make holes for rivets and fix this support on package with rivets. In the cases under consideration, this is a support fixed on the upper end of the packet. Then the remaining brackets are installed on the assembled assembly and the ends of the staples are bent to the package until the corrugated ribbons are completely straightened by the selected method. In case it is desired to produce a damping element with the highest UVC, the ends of all the brackets are folded to the stack simultaneously. In case it is desired to produce a damping element with the lowest UVC, the ends of all brackets are bent to the stack in series, the pair of ends of one bracket after the pair of ends of the next bracket, starting from the ends of the bracket located near the support fixed on the package, on its upper end. Support of the locking part of the damping element is put on the package. Holes are made in all supports and package and rivets are inserted into holes and riddled. Damping element or two assembled damping elements assembled in the form of a continuous span-length beam through a cutout or cutouts in the lock part of the blade with tension along their supports are installed in slots of projections of the blade halves. Diffusion welding under pressure in vacuum at temperature 450–500 °C in a die repeating the shape of the blade involves splicing aluminum supports of the package or packages with halves of the blade.
EFFECT: disclosed is a long hollow wide-chord fan of aircraft turbojet engine and method of its production.
5 cl, 13 dwg
