CN100494695C - Composite cavity fan blades - Google Patents

Abstract

This invention relates to a cavity fan blade of a composite material including an upper shell and a lower shell deducted to each other to form a cavity, in which a reinforced beam is arranged along a variable axis, a lead counterweight block is set at the outer end of the beam and glass fibers are winded around the beam to connect the counterweight block with a root metal joint, the two shells of the blade are molded by molding, glued glass fiber beams are winded around it in wet, then the entire blade is heated, pressed and solidified to a mold. The main body of the fan blade includes an upper shell and a lower shell molded by paper honeycomb and glass fiber cloth and so it is lighter than ordinary rotary-wing blades.

Description

Composite cavity fan blades

technical field

The invention relates to a ducted fan blade.

Background technique

As a pneumatic device that generates lift or thrust, the ducted fan has the characteristics of compact structure, safe operation, and low environmental noise. The so-called ducted fan is generally composed of a propeller or a small-diameter helicopter rotor with an externally expanded annular duct. Due to reasons such as high rotational speed and small lift surface solidity of the propeller, its lift efficiency is not as good as that of the rotor, and in order to meet the design needs of the aircraft, even A design with multiple rotor blades is required. However, the internal space of the duct is limited, so it is necessary to limit the swinging movement of the rotor blades up and down. When the blades rotate, a large centrifugal force is required, and the rotor blades are pulled by the centrifugal force so that they cannot swing up and down. Therefore, if it is necessary to use multiple rotor blades If the scheme is used, the weight of the entire rotor system will be relatively large. The conventional rotor blade is a solid structure, which is evenly distributed from the blade root to the blade tip, and the center of gravity of the entire blade is basically near the middle section of the blade. If the weight of the entire blade remains the same, the closer the center of gravity is to the tip, the greater the centrifugal force. Conversely, if the center of gravity of the entire blade can be made closer to the blade tip, its total weight can be relatively lighter under the premise of keeping the centrifugal force constant.

Contents of the invention

The technical problem to be solved by the present invention is to provide a design scheme for a fan blade with a composite material cavity. Conventional helicopter rotor blades are lighter, making them more suitable for use in multi-bladed fan systems.

In order to solve the above-mentioned technical problems, the composite cavity fan blade of the present invention is characterized in that it comprises a fan upper casing, a fan blade lower casing, a lead counterweight at the blade end, a reinforcing beam, a glass fiber bundle, and a blade root metal joint, Among them, the upper shell of the fan blade and the lower shell of the fan blade are glued together to form a fan cavity shell with a sandwich structure of composite materials. The cavity shell is equipped with reinforcing beams along the variable pitch axis, and the reinforcing beams are connected to the lead weight at the blade end. The glass fiber bundles are wound along the outside of the reinforcement beam to connect the blade tip weight with the metal joint of the blade root. The upper casing and the lower casing of the fan with composite material sandwich structure are molded by paper honeycomb and glass fiber cloth. Therefore, the fan system in which the fan blades constitute multiple blades is lighter than the system using conventional configuration rotor blades.

Description of drawings

Fig. 1 Schematic diagram of composite cavity fan blade structure

Figure 2 A-A sectional view of Figure 1

Label names in the figure:

1. Fan blade upper shell 2. Fan blade lower shell 3. Blade end lead weight 4. Reinforcing beam 5. Glass fiber bundle 6. Blade root metal joint

Detailed ways

As can be seen from Figures 1 and 2, the main body of the composite cavity fan blade is composed of a paper honeycomb and a glass fiber cloth molded upper shell 1 and lower shell 2 interlocked and glued together, and the interior is a cavity. A paulownia reinforcing beam 4 is arranged along the variable pitch axis, and the outer end of the reinforcing beam 4, that is, the tip of the blade is arranged with a lead counterweight 3 at the tip of the blade, so that the overall center of gravity is close to the tip of the blade, and the weight efficiency is high. In order to resist the large centrifugal force generated by the counterweight 3 when the blade rotates, a high-strength glass fiber bundle 5 is wound along the outside of the reinforcement beam 4 to connect the counterweight 3 and the blade root metal joint 6 . The upper and lower shells 1 and 2 of the blade are molded in advance, the glass fiber bundle 5 is dipped in glue and wound by wet method, and then the entire blade is heated and pressurized to be solidified and formed.

As can be seen from accompanying drawings 1 and 2, the main body of the composite material cavity fan blade is an upper shell 1 and a lower shell 2 molded by paper honeycomb and glass fiber cloth, which are quite light in weight, and the main weight is the lead distribution at the blade end. The weight is 3, so the center of gravity of the entire blade is close to the lead weight 3 at the tip of the blade. Under the premise of ensuring sufficient centrifugal force and limiting its waving motion, its weight is lighter than that of conventional rotor blades. Therefore, it is more suitable for forming a fan system composed of multiple blades.

Claims (2)

1, a kind of composite materials for fan blade with cavity, it is characterized in that comprising fan upper shell (1), fan blade lower shell body (2), the plumbous balancing weight (3) of end of blade, buttress brace (4), glass fiber bundle (5), blade root metal joint (6), wherein the mutual gluing of fan upper shell (1) and fan blade lower shell body (2) constitutes the fan cavity housing of composite material sandwich structure, this cavity enclosure interior is along displacement axis arranged buttress brace (4), buttress brace (4) is connected in the plumbous balancing weight (3) of end of blade, glass fiber bundle (5) along buttress brace (4) outer felt around, plumbous balancing weight of end of blade (3) and blade root metal joint (6) are coupled together.

2, composite materials for fan blade with cavity according to claim 1 is characterized in that the fan upper shell (1) of composite material sandwich structure and fan blade lower shell body (2) are by papery honeycomb and glass fiber cloth compression molding.

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