Fan casing

Abstract

The invention relates to the technical field of aero-engines and particularly provides a fan casing. A processing scheme of welding the casing with each stator blade is adjusted into a scheme that whole-ring stator blades with second outer rings are inserted into first outer rings, and welding and heat treatment processes are eliminated, so that the problems that the casing is deformed, the bodiesof the stator blades are misplaced, the axial length of a wear-resistant coating is insufficient due to a small axial clearance between a rotor and a stator, and the allowance of the casing is smalldue to a big margin plate are solved, and the vibration resistance of the casing is enhanced.

Description

technical field [0001] The invention relates to the technical field of aero-engines, in particular to a fan casing. Background technique [0002] At present, the whole ring casing generally adopts welding type: special-shaped holes are milled on the thin-walled casing, and the special-shaped holes are matched with the small gap of the upper edge plate of the stator and then welded by electron beam welding, so that the structure is simplified. [0003] The traditional welded fan case has the following defects: [0004] 1. Since the upper edge plate of each stator blade is welded separately, there are many weld seams, and the upper edge plate of the stator is prone to impenetrable welding or excessive stress, and cracks are prone to occur; [0005] 2. After the welding and heat treatment of the stator blades, the actual angular and axial positions of the blade body deviate from the theoretical position, the overall shrinkage of the casing and the flow path data deviate, which...

AI Technical Summary

Problems solved by technology

[0004] 1. Since the upper edge plate of each stator blade is welded separately, there are many weld seams, and the upper edge plate of the stator is prone to impenetrable welding or excessive stress, and cracks are prone to occur;

[0005] 2. After the welding and heat treatment of the stator blades, the actual angular and axial positions of the blade body deviate from the theoretical position, the overall shrinkage of the casing and the flow path data deviate, which affects the aerodynamic stability, and the deviation position has no statistical law;

[0006] 3. When the axial distance between the stator blade and the rotor blade of the next stage is small, since the rear flange of the casing is outside the welding stress zone of the upper edge plate, the axial length of the wear-resistant coating above the rotor blade of the next stage is reserved Insufficient, there is a risk that the tip of the rotor will be ground to the base of the fan casing. If the axial length of the wear-resistant coating is guaranteed, the flange edge is within the dangerous distance of the welding seam of the upper edge plate, and cracks are easy to initiate;

[0007] 4. When the thickness of the stator blade is large and the blade shape changes greatly, a larger upper edge plate of the stator is required, which will cause a small circumferential margin and insufficient strength reserve after the casing is milled out of a special-shaped hole;

[0008] 5. Due to maintenance needs, it is necessary to add a maintenance seat in the axial area where the stator blade is located. When the welding scheme is adopted, the welding seam of the maintenance seat and the welding seam of the upper edge plate are close or even cross, and cracks are easy to initiate. The assembly scheme requires a milling machine The outer surface of the box affects the batch production speed

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