Hollow blade thermal forming method and hollow blade inflation device

Abstract

The invention discloses a hollow blade thermal forming method and a hollow blade inflation device. The hollow blade thermal forming method comprises the following steps that interference air in a hollow blade and the movable inflation device is emptied, the hollow blade with the interference air emptied and the movable inflation device with the interference air emptied are connected through a connecting pipe, and a to-be-formed hollow blade is formed; the to-be-formed hollow blade is put into a bending and twisting die, the internal pressure of the hollow blade in the twisting process is adjusted, and a roughly-formed hollow blade is formed; and the roughly-formed hollow blade is put into a finishing mold, in the finishing forming process, the pressure intensity in the hollow blade is adjusted, thermal forming of the hollow blade is completed, inert gas is introduced in the whole forming process, and the effects of expanding a concave part of a cavity panel, obtaining the hollow blade with the accurate external profile and the smooth surface and lowering the requirement for the mold are achieved.

Description

technical field [0001] The invention relates to the field of forming fan blades of a turbofan engine, in particular to a forming method and an inflator for wide-chord hollow fan blades. Background technique [0002] The fan blades of the early turbofan engines were narrow-chord solid fan blades with raised shoulders. As the airflow flows through the shoulders, separation will occur, which will reduce the airflow efficiency, and the weight of the solid blades is too heavy, which is not conducive to the improvement of the thrust of the aircraft. To improve this problem, in recent years, scientists have developed wide-chord hollow blades, designed a cavity structure in the blade, and the cavity panel is supported by ribs, and the superplastic forming / diffusion welding (SPF / DB) processing method is adopted. Although this method can process hollow blades, there are many depressions on the surface of the formed hollow blades, and the external shape is not accurate, which affects t...

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Problems solved by technology

[0002] The fan blades of the early turbofan engines were narrow-chord solid fan blades with raised shoulders. As the airflow flows through the shoulders, separation will occur, which will reduce the airflow efficiency, and the weight of the solid blades is too heavy, which is not conducive to the improvement of the thrust of the aircraft. To improve this problem, in recent years, scientists have developed wide-chord hollow blades, designed a cavity structure in the blade, and the cavity panel is supported by ribs, and the superplastic forming / diffusion welding (SPF / DB) processing method is adopted. Although this method can process hollow blades, there are many depressions on the surface of the formed hollow blades, and the external shape is not accurate, which affects the overall performance of the part;

[0003] In order to solve the above problems, the Chinese invention patent with application number 201510945014.5 discloses a method for forming a hollow blade. The panel is welded by argon arc welding, riveted, and diffused to form a blank in the shape of a fan blade, and the formed blank is put into a mold Fill the mold with argon gas of 1.5-2.0MPa to form a hollow blade. Filling the mold with a high-pressure gas at one time will easily bulge the uncollapsed part of the hollow blade, causing wrinkles on the formed hollow blade;

[0004] The Chinese invention patent with the application number of 201510573864.7 discloses another molding method of the hollow blade. The blank of the hollow blade is put into a completely closed mold cavity, and gas is filled into the cavity of the hollow blade. High air pressure, after reaching the maximum air pressure, control the air pressure to remain unchanged. Although this molding method can solve the problem that the hollow blade will not bulge the uncollapsed part due to the excessive pressure of the gas in the mold molding process. However, due to the large difference between the shape of the blank and the formed part, the deformation of the blade during the forming process is too complicated, and it needs to be filled with a high-pressure gas to expand the depression, which has higher requirements for the mold;

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