JPH02187599A - Dome for high speed airframe - Google Patents

Abstract

PURPOSE:To make a dome excellent in hardness, strength, and heat resistance and applicable to high speed airframe and to a compound piloting system by setting up a dome for a high speed airframe by combining a light-transmitting type and a non-light-transmitting type oxide-nitride o aluminum ceramics. CONSTITUTION:An oxide-nitride of aluminum ceramics, referred to also as Alon, has specially high strength, hardness, and heat resistance. The dome is void and hemispherical in structure as a whole, about a half of the hemisphere being built of light-transmitting Alon 1 and the remaining half being built of non-light-transmitting Alon 2. An infrared ray sensor 3 and a radio antenna 4 are installed inside the dome; these installations make composite guiding possible with respect to infrared rays and radio waves. Light-transmitting Alon and non-light-transmitting Alon are fastened to each other firmly by heat- resistant adhesion or by a joining means 5. Since non-light-transmitting Alon transmits radio waves and light-transmitting Alon is excellent in transmitting infrared rays, suitable combination of these materials makes it possible to set up a large scale-dome for a composite guiding system easily and economically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dome that is attached to the tip of a high-speed flying object such as a missile and protects internal devices such as a radio antenna and an infrared sensor.

[Conventional technology]

There are several types of missiles, including surface-to-air, air-to-air, and air-to-ground, and their guidance methods are broadly divided into radio wave guidance and infrared light guidance.

The radio wave guidance type uses a radio antenna to receive radio waves emitted by a target object or reflected waves from the target object, confirm the position of the target object, and guide the target object. Therefore, the dome of a radio-guided missile is made of a material such as glass that easily transmits radio waves. However, a dome made of glass has insufficient heat resistance because its tip is heated to a high temperature by aerodynamic heating when the speed is increased.

In the infrared light guidance type, the infrared light emitted by the target object is received by an infrared sensor to confirm the position of the target object and guide it. Therefore, the dome used for infrared light guidance is made of magnesium fluoride (MgF) or zinc sulfide (Z), which have good infrared light transmittance.
nS ) etc. are used. However, MgF and ZnS
etc. have a low hardness of about 600 or less, and have the disadvantage that the surface is easily damaged by collision with sand particles, ice particles, etc. floating in the atmosphere, and the translucency is easily reduced. or,
In terms of heat resistance, the melting point or sublimation point is 1300 to 900.
C, which could not be said to be sufficient under ultra-high speed conditions.

[Problem to be solved by the invention]

As mentioned above, conventional domes for high-speed flying objects have problems in terms of material hardness and heat resistance.

Moreover, in the United States, research has recently begun on a composite guidance system that combines infrared light guidance and radio wave guidance in order to counter missile guidance jamming, but conventional dome materials such as glass, MgF, and ZnS cannot It has been difficult to obtain a dome that transmits both external light and radio waves and is durable under high speed conditions.

Therefore, in view of the conventional circumstances, the present invention provides a dome for high-speed flying objects that has excellent hardness, strength, and heat resistance and can be applied to high-speed flying objects, and is also compatible with complex guidance types. The purpose is to provide the following.

[Means to solve the problem]

In order to achieve the above object, the dome for a high-speed flying object according to the present invention is characterized by being composed of a combination of translucent and non-translucent aluminum oxynitride ceramics.

1'lt'' Aluminum It is known.

-12 Translucent materials can be manufactured by a pressure sintering method such as a hot press method, and non-transparent materials can be manufactured by an atmospheric pressure sintering method.

Nylon has a bending strength of 30 kg/ss and a hardness of 1
It has a high mechanical strength of about 970 and a melting point of 2140.
It has a high C and has excellent heat resistance. Furthermore, the dielectric constant is 8.
5. The dielectric loss is approximately 5×10''-', and the transmittance of radio waves (microwaves) is also excellent.

Non-transparent Neylon does not transmit infrared light but transmits radio waves, and translucent Neylon transmits both infrared light and radio waves. Therefore, a dome made only of non-transparent nylon can be used for radio wave induction type, and a dome made only of translucent nylon can be applied to any of the infrared light induction type, radio wave induction type, and composite induction type.

However, in the case of a composite induction type, it is necessary to house both an infrared sensor and a radio antenna within the dome, so the dome size is large, and it is difficult due to manufacturing technology to manufacture the entire dome from transparent nylon. There is a problem of high cost.

The dome structure of the present invention was devised in view of these problems, and since the dome is constructed by a combination of translucent and non-transparent kneelons, manufacturing is relatively easy even for complex induction types. It has the characteristics of being easy and low cost to manufacture.

The dome of the present invention can be manufactured relatively easily and at low cost by gluing or joining each part of the light-transmitting and non-light-transmitting kneelon with a heat-resistant adhesive.

A specific example of the dome for high-speed flying objects of the present invention is shown in FIGS. 1 and 2.

This dome is a hollow hemisphere as a whole, and approximately half of the hemisphere is composed of a translucent kneelon part 1, and the remaining half is composed of a non-transparent kneelon part 2.

An infrared sensor 3 and a radio antenna 4 are arranged inside the dome, making it possible to conduct combined guidance of infrared light and radio waves.

The light-transmitting kneelon and the non-light-transmitting kneelon are firmly fixed to each other by heat-resistant adhesive or joint portion 5.

Note that the sizes of the translucent kneelon part 1 and the non-transparent kneelon part 2 can be arbitrarily combined depending on the guidance method and the like. Further, instead of the non-transparent Neylon, non-transparent heat-resistant ceramics such as alumina-based, spinel-based, silicon nitride-based, aluminum nitride-based, etc. may be used.

[Effect]

Translucent and non-transparent aluminum oxynitride ceramics (Nylon) constituting the dome for high-speed flying objects of the present invention are made of low dielectric constant glass and MgF, which are conventional dome materials.
It has significantly higher strength, hardness, and heat resistance than other materials such as ZnS and ZnS.

For example, since the hardness is on the order of 300 yen, it is resistant to damage even when hit by sand grains or ice grains, and therefore has excellent durability. In addition, it has excellent heat resistance with a melting point of 2140 tZ'', so it can sufficiently withstand temperature increases caused by aerodynamic heating at high speeds.

Non-transparent Neelon transmits radio waves but does not transmit infrared light, but it can be manufactured by sintering without pressure, so it has the advantage of economically manufacturing relatively large materials.

On the other hand, translucent Nealon is 80% resistant to infrared, visible, and ultraviolet light.
%, and has excellent infrared light transmittance, particularly at a wavelength of 3 to 4 μm, and the light transmittance can be further improved by applying a reflective coating to the surface. In addition, since translucent Nylon has excellent radio wave transmittance, it can be used as a dome for infrared light guidance, radio wave guidance, or a combination of both.

By appropriately combining these materials with the same composition but different only in transmissivity as described above, it becomes possible to construct a large dome of the composite induction type technically easily and economically.

The shape of the entire dome may be, in addition to the hemispherical shape described above, a streamlined shape with less air resistance, a cone shape, a pyramid shape, or the like.

Furthermore, since the translucent kneelon and the non-transparent kneelon have almost the same coefficient of thermal expansion of 5.2 x 10 /l, thermal distortion during aerodynamic heating can be minimized even if they are bonded or bonded together.
There is no risk of peeling etc. Furthermore, since the dielectric constant and dielectric loss are almost the same, a dome with no distortion in radio wave characteristics can be obtained as a whole.

〔Example〕

Neelon powder with a purity of 99.3% and an average particle size of 2.5 μm was molded into a hemispherical shape with a diameter of 200 mm and a thickness of 10 mm by the OIP method, and after drying, it was sintered in the air at a temperature of 19,000 mm.

The sintered body is non-transparent white, has a porosity of 3% or less, and has a dielectric constant of 8.0 as measured by the standing wave method using a waveguide.
58, and the dielectric loss was 5×10−′. Also, wavelength 3~
The transmittance of infrared light at 4 μm was 0%. High purity spinel powder with a purity of 99.8% and an average particle size of 1.5 μm was heated at 1950 C by a vacuum hot press method using a carbon mold. It was sintered into a hemispherical shape with a diameter of 200mm and a thickness of 20u using a 300mm diameter. The sintered body was colorless and transparent, had a porosity of 0.15 or less, and was measured using the same method as above, and had a dielectric constant of 8.6 and a dielectric loss of 5.2X10''-'.
The infrared light transmittance of the specimen mirror-polished to a thickness of 4 mm at a wavelength of 3 to 4 μm was approximately 78%.

Furthermore, when an antireflection coating was applied to the surface of this material, the maximum transmittance increased to 88%.

The above-mentioned non-transparent nailon was ground using a curve generator to create a hemispherical dome with a thickness of approximately 4 mm. or,
The above-mentioned translucent spinel was similarly made into a hemispherical dome, and both sides were mirror-polished to create a hemispherical dome with a thickness of about 4 mm.

Each dome was cut into approximately 172 pieces, and the translucent kneelon was coated with anti-reflection coating, and the translucent and non-transparent parts were glued together with a heat-resistant ceramic adhesive to form a hemispherical shape. Two domes were created.

The infrared light transmittance of this dome was 80% or more, and it was confirmed that the infrared sensor was operating normally. Furthermore, the transmission loss of radio waves was less than 2 tiE, and the antenna operated normally. Based on these results, it was found that the dome is useful as a composite induction dome.

〔Effect of the invention〕

According to the present invention, it is made of aluminum oxynitride (Nylon) ceramic material with excellent hardness, strength, and heat resistance, and has excellent durability and is applicable to high-speed flying objects.
Furthermore, it is possible to provide a dome for high-speed flying objects that is compatible with any of the radio wave guidance type, infrared light guidance type, or composite guidance type.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a specific example of the dome for high-speed flying objects of the present invention, and FIG. 2 is a plan view thereof. l... Translucent kneelon part 2... Non-transparent kneelon part 3... Infrared sensor 4... Radio antenna 5... Joint part

Claims (1)

[Claims] (1) A dome attached to the tip of a high-speed flying object,
A dome for high-speed flying objects characterized by being constructed from a combination of translucent and non-transparent aluminum oxynitride ceramics.