Classification of receiver parts

According to the design structure, it can be divided into two categories, namely the ring receiver and the box receiver. The ring receiver can be further divided into an integral ring receiver, a split ring receiver and a ring receiver with a rectifying support plate. Among them, the integral ring casing, such as the combustion chamber casing, the turbine casing, etc.; the main casing, such as the compressor casing; the casing with the rectifying support plate, such as the air intake casing, the intermediate casing, the diffusion casing, etc.; Box casing, such as accessory casing, two-speed transmission casing. If the casing is classified by function, on a turbojet engine, there are intake processing casing, low-pressure compressor casing, high-pressure compressor casing, combustion chamber casing, bearing casing, turbine casing, and afterburner casing. Case, central transmission case, accessory case, etc.; on turbofan engines, different cases from turbojet engines include air intake case, fan case, intermediate case, turbine rear case, and external culvert Box etc.

Classified by material, there are aluminum alloys, titanium alloys, high-temperature alloys, high-strength steels, composite casings, etc. For example: fan casings and accessory casings are mostly made of titanium alloy and aluminum alloy materials; the low-pressure part of the compressor casing is generally made of high-strength steel, and the high-pressure part is generally made of titanium alloy; the turbine casing is mostly made of nickel-based superalloy and High-strength steel material.

The picture below shows the case division of turbojet engine and turbofan engine.

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Among them, the main material of the fan casing is titanium alloy, which has the characteristics of high hardness, high strength, corrosion resistance, and high temperature resistance, which are difficult to process. The tool wear is severe, the work hardening phenomenon is serious, and the cutting is difficult.

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Figure 2. Fan case

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Figure 3. The front casing of the combustion chamber

Structural characteristics of engine casing

With the upgrading of aero engines, the structure of the engine casing is becoming more and more complicated.

(1) The structural characteristics of the integral ring casing:

Composed of the casing wall and the front and rear mounting edges, it is generally thin-walled cone or cylinder. The outer surface of the shell has ring-shaped stiffeners, ring belts, and bosses; the inner surface has ring grooves, cylindrical ring belts and spiral grooves; cylindrical ring There are circumferential oblique holes distributed on the belt; radial holes, special-shaped holes and heterosexual grooves are arranged on the shell wall

(2) Structural features of the split ring casing:

This type of casing generally has a longitudinal mounting edge, which is in the shape of a cone or a cylinder. The inner surface has an annular groove or a T-shaped groove and a spiral groove; the outer surface has a reinforcing rib, a supporting platform, a limiting boss, and various functional convexities. Table and heterogeneous boss; there are mounting holes, positioning holes, vent holes, radial holes and special-shaped holes on the casing wall

(3) Structural features of the casing with rectifying support plate:

This type of casing has a cast structure and a welded structure, and is generally composed of an outer ring, an inner ring and a hollow rectifying support plate. The inner and outer ring walls are thicker and are provided with radial holes; the end face of the inner ring is provided with bolt holes; the outer ring is provided with positioning holes and connecting holes; and the outer surface is provided with mounting seats and planes.

(4) Structural features of the box casing:

This type of casing has a complex appearance, thin wall, and poor rigidity. The surface of the casing has mounting holes, planes, joint surfaces, reference surfaces, positioning pin holes, threaded holes, oil passage holes, etc. Most of the blanks are sand cast magnesium alloys.

Process analysis of the casing is an important front-end work for formulating the casing processing technology and optimizing the casing process. The so-called process analysis refers to the analysis of the manufacturing process of parts. Manufacturing process analysis analysis includes two parts: structural process analysis and manufacturing process analysis. Structural manufacturability analysis is for the product or component design process, and manufacturing process analysis is for the manufacturing process. The so-called structural manufacturability refers to the feasibility and economic analysis of the design object under the conditions of meeting the requirements of use. The manufacturing process refers to the description of the entire process of manufacturing the product. The manufacturing process uses mechanical processing methods to directly change the shape, size, mutual position and surface quality of the surfaces of the blank, and make it a process of qualified parts. It is a skill and method. And a collection of programs. The process formulation of mechanical parts is a complex task. It requires that the most reasonable process be worked out under given conditions, and the harmonization of quality, productivity and economy is achieved.