JP2016161270A - Radome ring for flying body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent increase of flight times of flying bodies in these days, and damage of a radome resulting from increasing flight speed.SOLUTION: A slit is provided in a radome ring for a flying body connecting a radome provided at the tip part of the flying body and a shell to be a body portion of the flying body. Consequently, deformation of expanding to radial outside of the radome ring can be absorbed in an in-plane direction of the radome ring, and then heat stress occurring at a portion connecting the radome and the radome ring can be reduced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a flying object. In particular, the present invention relates to a flying body that joins a radome portion and a shell portion of a flying body via a radome ring.

The flying object radome consists of a radome that protects the radar at the tip of the flying object, a shell that is the flying object body, and a ring that joins the radome and the shell (hereinafter referred to as a radome ring). ing.
Since the flying body flies at supersonic speed during use, it is heated by aerodynamic heating, and for example, the air temperature of the radome at the tip exceeds 1000 ° C. For this reason, a dielectric material having both heat resistance and radio wave transmissivity, specifically, ceramics such as alumina, cordierite, and fused silica sintered body is used as the radome material.
Ceramics generally have a low coefficient of thermal expansion and have a value of about 0.1 × 10 ⁻⁶ to 2 × 10 ⁻⁶ / K. On the other hand, an aluminum alloy is used as the shell material from the viewpoint of weight reduction and cost. The thermal expansion coefficient of the aluminum alloy is about 23 × 10 ⁻⁶ / K. Thus, the radome and shell of the flying body have a large difference in thermal expansion. In the case of a structure where both are directly joined, if the temperature rises due to aerodynamic heating during flying, a large thermal stress is generated at the joint. .
Therefore, the radome and the shell are joined via a radome ring made of FRP (fiber reinforced plastic, thermal expansion coefficient: 4 × 10 ⁻⁶ to 10 × 10 ⁻⁶ / K), which is highly rigid and has a relatively low thermal expansion coefficient. By doing so, a flying body with reduced thermal stress is disclosed (for example, see Patent Documents 1 to 3).

JP 2003-21500 A JP-A-2-166806 JP 2012-172868 A

In recent years, aerodynamic heating applied to a flying object has increased due to an increase in flying time and an increase in flying speed, and accordingly, the temperature of the flying object has also increased. Therefore, the shell in which the aluminum alloy having a high coefficient of thermal expansion is used is deformed so as to expand outward in the radial direction due to thermal expansion.
Along with the deformation of the shell, the radome ring is deformed so as to expand outward in the radial direction, so that a large thermal stress is applied to a portion where the radome and the radome ring are joined. For this reason, the radome which uses the ceramic which is a brittle material (material which has the property to destroy before it deform | transforms) had the subject that it could not endure the said thermal stress, and destroyed.
Further, as the flying time and aerodynamic heating increase, the amount of heat flowing from the shell into the radome ring increases, so that the temperature of the radome ring rises and thermally expands radially outward. For this reason, as described above, there is a problem that a large thermal stress is applied to a portion where the radome and the radome ring are joined, and the radome is destroyed.

  The present invention has been made in order to solve the above-mentioned problems, and can relieve the thermal stress generated in the portion where the radome and the radome ring are joined by the thermal expansion of the shell, and can reduce the amount of heat flowing from the shell into the radome ring. An object is to provide a radome ring that can be reduced.

  A flying object radome ring according to the present invention is a flying object radome ring that joins a radome provided at a tip of a flying object and a shell which is a main body part of the flying object, and has a circular upper surface. A cylindrical shape with both open and lower surfaces is formed, and an elliptical slit having a long length in the direction from the upper end to the lower end is provided between the upper end and the lower end of the cylindrical shape.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal stress which arises in the site | part which joins a radome and a radome ring can be relieved, and destruction of the radome which uses a brittle material can be prevented.

It is a block diagram explaining the structure of the flying object radome by Embodiment 1 which concerns on this invention. It is a figure explaining the deformation | transformation expand | swelling toward the radial direction outer side exerted on a radome ring by the shape of the radome ring by Embodiment 1 which concerns on this invention, and the thermal expansion of a shell. It is sectional drawing of the fastening part of the radome ring and shell by Embodiment 1 which concerns on this invention, and sectional drawing explaining the deformation | transformation of the shell at the time of fastening of a radome ring and a shell.

  FIG. 1 is a diagram illustrating the configuration of a flying object radome according to Embodiment 1 of the present invention. In FIG. 1, a flying object 100 is fitted and bonded to a radome 1 that protects a radar antenna provided at the tip of the flying object, a shell 3 that is a flying object body, and a radome 1. And the radome ring 2 fitted and fastened, and a heat insulating material 4 that prevents the radome ring 2 from rising in temperature due to aerodynamic heating. The radome ring 2 is a cylindrical ring whose upper and lower surfaces are open, and when viewed from the upper surface direction or the lower surface direction, the radome ring 2 has a circular shape with a ring material having a thickness. The material of the radome ring 2 is, for example, FRP. In addition, about the structure of the flying body which is not necessary for description of this invention, the description is abbreviate | omitted.

In the present embodiment, the material of the radome 1 is a dielectric material having both heat resistance and radio wave transmission, specifically, ceramics such as alumina, cordierite, fused silica sintered body (thermal expansion coefficient: 0). .About.1 × 10 ^{−6 to} 2 × 10 ⁻⁶ / K).
The shell 3 is made of an aluminum alloy (thermal expansion coefficient: about 23 × 10 ⁻⁶ / K) from the viewpoint of weight reduction and cost. The radome 1 and the shell 3 have a large difference in thermal expansion. In the structure in which both are directly joined, when the temperature rises due to aerodynamic heating during flight, a large thermal stress is generated at the joint. Therefore, the radome ring 2 is disposed between the radome 1 and the shell 3 for the purpose of relaxing the thermal stress.

Here, the radome ring 2 is close to the thermal expansion coefficient of ceramics in order to prevent the radome 1 made of ceramics, which is a brittle material (a material having a property of breaking before being deformed) by the thermal stress. A low thermal expansion material such as invar (thermal expansion coefficient: 1.2 × 10 ⁻⁶ / K), which is rigid, is used.

  FIG. 2 shows the shape of the radome ring 2 according to the first embodiment of the present invention. As shown in FIG. 2, the radome ring 2 has a cylindrical shape in which both a circular upper surface and a lower surface are open. A plurality of elliptical slits 5 having a long length from the upper end to the lower end of the cylinder are provided on the cylindrical side surface of the cylindrical radome ring 2 in the circumferential direction of the cylinder. A plurality of holes 6 for screwing the radome ring 2 and the shell 3 are provided in the circumferential direction of the cylinder.

As shown in FIG. 2, the radome ring 2 is deformed due to thermal expansion of the shell 3 due to aerodynamic heating during flight, and is deformed 7 that expands radially outward.
The flying object radome ring according to the present embodiment is provided with a plurality of slits 5 for the purpose of absorbing the deformation 7 in the in-plane direction of the radome ring 2.
By providing the slit 5, the radome ring 2 is not only radially outward but also in the in-plane direction of the radome ring 2, that is, in the vertical direction that is perpendicular to the circumferential direction of the cylindrical side surface and the circumferential direction. Since it spreads, the deformation 7 that expands radially outward can be suppressed.
As a result, it is possible to relieve the thermal stress generated at the portion where the radome 1 and the radome ring 2 are joined.

Here, the slit 5 is formed so as not to reach the upper end and the lower end of the radome ring 2.
If the slit 5 is formed so as to reach the upper end or the lower end of the cylindrical radome ring 2 whose upper and lower surfaces are open, the radome ring 2 can be easily bent in the radial direction. The bending rigidity of the ring 2 is reduced.
If the bending rigidity of the radome ring 2 is small, the deformation 7 that expands radially outward due to the thermal expansion of the shell 3 cannot be suppressed by the radome ring 2, and the radome 1 and the radome ring 2 are joined at a large portion. Thermal stress will occur.
Therefore, in the radome ring 2 according to the present embodiment, the slit 5 is formed between the upper end and the lower end of the radome ring 2 as shown in FIG. Thus, the bending rigidity of the radome ring 2 is maintained so that the slit 5 does not reach either the upper end or the lower end of the radome ring 2.

  Also, if the width of the slit 5 is too large, the section modulus Z of the radome ring 2 becomes small, and the stress σ (σ = M / Z) obtained by dividing the bending moment M generated by the aerodynamic load during flight by the section modulus. Becomes larger. For this reason, in order to maintain the strength of the radome ring 2, the slit 5 is formed to be as small as possible. For example, the width of the slit 5 is set to a width that expands in the in-plane direction when the radome ring 2 expands in the in-plane direction along with the radially outer side by aerodynamic heating during flight.

FIG. 3 is a sectional view when the radome ring 2 and the shell 3 according to the first embodiment of the present invention are fastened.
A heat insulating material is attached around the radome ring 2 to prevent a temperature rise due to aerodynamic heating. As a result, the temperature rise due to aerodynamic heating of the radome ring 2 can be prevented, but in general, the thermal conductivity (about 236 W / mK) of the aluminum alloy used in the shell 3 is high. When the temperature of the shell 3 rises due to this, the amount of heat of the shell 3 flows into the radome ring 2. Further, the radome ring 2 and the shell 3 are fitted and fastened. However, in the case of the radome ring 2 using invar, the rigidity of the shell 3 is lower than the rigidity of the radome ring 2, as shown in FIG. In addition, the fastening portion of the shell 3 comes into contact with the radome ring 2.

Therefore, the radome ring according to the present embodiment is provided with a bush 8 having a low thermal conductivity at a portion where the radome ring 2 is fastened and in contact with the shell 3.
The bush 8 is made of, for example, a resin (thermal conductivity: about 0.2 to 0.4 W / mK) or the like. The bush 8 is a cylindrical shape that can be fitted to a shaft or a cylindrical member to fill a gap. It is a mechanical part. By using the bush 8 at the fastening portion of the radome ring 2 and the portion in contact with the shell 3, the thermal conductivity of the fastening portion of the radome ring 2 can be lowered.

As described above, since the thermal conductivity of the fastening portion of the radome ring 2 is lowered, the amount of heat 9 flowing from the shell 3 into the radome ring 2 can be reduced, and the temperature rise of the radome ring 2 can be suppressed.
Thereby, the deformation | transformation expand | swelling toward the radial direction outer side by the thermal expansion of the radome ring 2 is suppressed, The thermal stress produced in the site | part which joins the radome 1 and the radome ring 2 can be relieve | moderated, As a result, destruction of the radome 1 Can be prevented.

1 radome, 2 radome ring, 3 shell, 4 heat insulating material, 5 slit, 6 hole for fastening the radome ring and the shell, 7 deformation that expands radially outward due to thermal expansion of the shell, 8 bush, 9 from the shell to the radome The amount of heat flowing into the ring, 100 flying objects.

Claims (4)

A radome for a flying object that joins a radome provided at the tip of the flying object and a shell that is a body part of the flying object,
It has a cylindrical shape with an open top and bottom surface.
A flying object radome ring comprising an elliptical slit having a long length in the direction from the upper end to the lower end between the upper end and the lower end of the cylindrical shape.   2. The flying object radome ring according to claim 1, wherein a width of the oval slit is the same as a width in which the flying object radome ring expands in an in-plane direction by aerodynamic heating during flying. .   The flying body radome ring according to claim 1, wherein a plurality of the slits are provided along a circumferential direction.   The flying body radome ring according to any one of claims 1 to 3, wherein a mechanism part having a low thermal conductivity is provided at a joint portion with the shell.

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