JP7325237B2 - Radome for flying objects - Google Patents

Description

The present invention relates to a flying object radome for protecting an antenna of a flying object.

A flying object that flies toward a target by radio wave induction is known. A radar antenna for detecting targets is attached to the tip of the projectile. The projectile flies at supersonic or hypersonic speeds and makes sharp turns toward its target. Therefore, a flying object radome is attached to the tip of the shell, which is the body portion of the flying object, so as to protect the antenna from aerodynamic heating or aerodynamic load. Patent Document 1 discloses that a radome for a flying object has a radome main body and a radome ring, the radome main body is joined to a shell via a radome ring, and a radome main body and a radome ring. is fixed with an adhesive.

The main body of the radome has heat resistance and thermal shock resistance that allow it to be used in high-temperature environments due to aerodynamic heating generated by supersonic or hypersonic flight, as well as a dielectric that allows radio waves transmitted and received by the antenna to pass through. Constructed by body material. Examples of the constituent material _{of the} radome body are alumina ( _Al2O3 ), cordierite ( _{2MgO.2Al2O3.5SiO2} ), fused silica ( _{SiO2 )} , and silicon nitride _{( Si3N4} ). be. These materials are ceramics excellent in heat resistance and thermal shock resistance, and have linear expansion coefficients of 0.1×10 ⁻⁶ /K to 2×10 ⁻⁶ /K. On the other hand, the shell is made of iron (Fe) or aluminum (Al) having high rigidity. These materials have coefficients of linear expansion ranging from 15×10 ⁻⁶ /K to 30×10 ⁻⁶ /K, which are higher than the materials forming the radome body.

In this way, when the radome main body and the shell, which are made of different materials with different coefficients of linear expansion, are directly combined, a large thermal stress is generated at the junction in a high-temperature environment. Therefore, the radome ring is made of a material having an intermediate coefficient of linear expansion between the coefficient of linear expansion of the radome body and the coefficient of linear expansion of the shell. The radome ring is made of fiber-reinforced plastic (hereinafter referred to as FRP), which has high rigidity and a coefficient of linear expansion smaller than that of the shell. The coefficient of linear expansion of FRP is from 4×10 ⁻⁶ /K to 10×10 ⁻⁶ /K.

JP-A-2003-238929

However, the temperature generated in the radome main body and the radome ring becomes higher than before due to aerodynamic heating associated with increased speed and longer flight time of the projectile. In such a high-temperature environment, the technology described in Patent Document 1 above has the problem that the temperature generated in the radome main body and the radome ring exceeds the heat-resistant temperature of the adhesive and the heat-resistant temperature of the FRP radome ring. was there.

The present invention has been made in view of the above, and the radome ring keeps the radome main body fixed to the shell even in a high-temperature environment due to aerodynamic heating associated with increased speed and longer flight time of the projectile. An object of the present invention is to obtain a radome for flying objects.

In order to solve the above-described problems and achieve the object, a radome for a flying object according to the present invention includes a radome body, a radome ring, a fixing part, a heat insulator, and a thermal stress relaxation material. . The radome main body constitutes the tip of a flying object that flies toward a target by radio wave induction, and is installed on the fuselage of the flying object. The radome ring is fitted to the exterior of the fuselage and the interior of the radome body. The fixing component mechanically fixes the radome ring and the radome body. A heat insulating material is provided on the outer peripheral surface of the joint between the fuselage and the radome body. The thermal stress relaxation material is provided on the outer peripheral surface of the radome body corresponding to the joint with the radome ring.

According to the present invention, the radome ring can keep the radome main body fixed to the shell even in a high-temperature environment due to aerodynamic heating associated with increased speed and longer flight time of the projectile.

1 is a partial perspective view showing an example of a configuration of a flying object having a radome for a flying object according to an embodiment; FIG. FIG. 2 is a perspective view showing an example of a configuration of a radome ring included in the radome for a flying object according to the embodiment; FIG. 2 is a top view showing an example of a configuration of a radome ring included in the radome for a flying object according to the embodiment; FIG. 2 is a side view showing an example of a configuration of a radome ring included in the radome for a flying object according to the embodiment; FIG. 2 is a partial cross-sectional view schematically showing an example of bonding with a radome ring included in the radome for a flying object according to the embodiment; FIG. 4 is a diagram for explaining the function of a radome ring included in the radome for a flying object according to the embodiment; A diagram for explaining the function of the thermal stress relaxation material in the embodiment. A diagram for explaining the function of the heat insulating material in the embodiment.

EMBODIMENT OF THE INVENTION Below, the radome for flying bodies concerning embodiment of this invention is demonstrated in detail based on drawing. In addition, this invention is not limited by this embodiment.

Embodiment.
FIG. 1 is a partial perspective view showing an example of the configuration of a flying object having a flying object radome according to an embodiment.

A flying object 1 flies toward a target by radio wave induction. A flying body 1 includes a shell 11 as a body and a flying body radome 12. - 特許庁

The shell 11 is the body portion of the flying object 1 . An example of the constituent material of the shell 11 is iron or aluminum. The coefficient of linear expansion of these materials is 15×10 ⁻⁶ /K to 30×10 ⁻⁶ /K. An antenna 111 is provided at the tip of the shell 11 . Antenna 111 transmits and receives radio waves for measuring the distance and bearing to a target.

The flying object radome 12 has a radome main body 13 and a radome ring 14 . The radome main body 13 has a streamlined shape with a pointed tip so that it can fly at high speeds by reducing aerodynamic resistance. It is hollow. A hollow rear end is connected to the front end of the shell 11 via a radome ring 14 . By covering the tip of the shell 11 with the radome body 13 in this manner, the antenna 111 provided at the tip of the shell 11 is protected. The radome main body 13 is made of a dielectric ceramic material that has heat resistance and thermal shock resistance against temperature rise due to aerodynamic heating and that has radio wave transparency. Examples of dielectric ceramic materials are alumina, cordierite, fused silica, and silicon nitride. The coefficient of linear expansion of these materials is 0.1×10 ⁻⁶ /K to 2×10 ⁻⁶ /K.

The radome ring 14 is a member that connects the shell 11 and the radome body 13 . FIG. 2 is a perspective view showing an example of a configuration of a radome ring included in the flying object radome according to the embodiment. FIG. 3 is a top view showing an example of a configuration of a radome ring included in the flying object radome according to the embodiment. FIG. 4 is a side view showing an example of a configuration of a radome ring included in the flying object radome according to the embodiment. As shown in FIGS. 2 and 3, the radome ring 14 is a ring having a cylindrical shape with the front end side and the rear end side of the flying object 1 opened. As shown in FIG. 4 , the radome ring 14 has a shell fitting portion 14 a fitted to the outside of the shell 11 and a radome fitting portion 14 b fitted to the inside of the radome body portion 13 . The shell fitting portion 14 a has a constant radius in the axial direction of the radome ring 14 . A plurality of through holes 141 for fixing to the shell 11 by fixing parts are provided in the side surface of the cylindrical shell fitting portion 14a along the circumferential direction. The radius of the radome fitting portion 14 b decreases toward the tip of the flying object 1 so as to contact the inner surface of the radome main body 13 . A plurality of through holes 142 for fixing to the radome main body 13 with fixing parts are also provided on the side surface of the cylindrical radome fitting portion 14b.

In a flying object 1 that flies at supersonic or hypersonic speed and becomes hot due to aerodynamic heating, the temperature between the radome body 13 and the radome ring 14 may exceed the heat-resistant temperature of FRP. Therefore, in the present embodiment, radome ring 14 is made of an alloy material that has a higher heat resistance than FRP and a lower coefficient of linear expansion than the material that makes up shell 11 . Such alloy materials are hereinafter referred to as low thermal expansion alloys. Examples of low thermal expansion alloys are Invar, an alloy containing iron and 36 wt% nickel, Super Invar, an alloy containing iron, 32 wt% nickel, and 4 wt% cobalt, iron, 29 wt% nickel, and 17 wt%. Kovar is an alloy containing cobalt from These linear expansion coefficients are from 0.8×10 ⁻⁶ /K to 5.46×10 ⁻⁶ /K.

FIG. 5 is a partial cross-sectional view schematically showing an example of bonding with a radome ring included in the radome for a flying object according to the embodiment, and is an enlarged cross-sectional view of region R in FIG. In this figure, illustration of the shell 11 is omitted. In the present embodiment, as shown in FIG. 5, a fixing component 31 is used to mechanically fix the radome body 13 and the radome ring 14 together. This is because the temperature between the radome body 13 and the radome ring 14 exceeds the heat-resistant temperature of the adhesive due to aerodynamic heating, so that they cannot be fixed with the adhesive. An example of the fixed part 31 is a pin or bolt. That is, in the present embodiment, for example, pins or bolts are used to fasten the radome body 13 and the radome ring 14 together. As between the radome body 13 and the radome ring 14 , the radome ring 14 is fixed between the shell 11 by a fixing component.

At a temperature heated by aerodynamic heating, the radome body 13 may be destroyed by thermal stress caused by the difference in coefficient of linear expansion between the radome body 13 and the radome ring 14 . Therefore, as shown in FIGS. 2 to 5, the radome ring 14 is provided with a plurality of slits 143 that reduce the rigidity of the radome ring 14 . As shown in FIG. 4, the open end 143a, which is one end of the plurality of slits 143, is positioned on the end surface of the cylinder of the radome ring 14 on the tip side, and the other end, which is the closed end, is located at the end of the cylinder. The portion 143b is provided within the shell fitting portion 14a. The slit 143 is provided in a direction parallel to the axis of the radome ring 14, as an example. This slit 143 relaxes the thermal stress caused by the difference in coefficient of linear expansion between the radome body 13 and the radome ring 14 .

Returning to FIG. 1 , the flying object 1 further includes a thermal stress relaxation material 21 and a heat insulating material 22 . The thermal stress relaxation material 21 is arranged on the outer peripheral surface of the radome main body 13 near the joint with the radome ring 14 . The thermal stress relaxation material 21 is ring-shaped and laminated so as to wrap around the outer peripheral surface of the joint with the radome ring 14 . That is, the thermal stress relaxation material 21 is arranged on the outer peripheral surface of the fitting range of the radome main body 13 with the radome ring 14 .

The thermal stress relaxation material 21 is a member that generates compressive stress in the rear end portion of the radome main body 13 due to the difference in coefficient of linear expansion between it and the radome main body 13 at a temperature heated by aerodynamic heating. The thermal stress relaxation material 21 is made of a material having a coefficient of linear expansion smaller than that of the radome body 13 . The coefficient of linear expansion of the thermal stress relaxation material 21 is preferably smaller than the coefficient of linear expansion of the radome main body 13 and is close to zero. The thermal stress relaxation material 21 may be a material having a negative coefficient of linear expansion. An example of the thermal stress relaxation material 21 is FRP using carbon fiber having a linear expansion coefficient of −0.7×10 ⁻⁶ /K to −1.2×10 ⁻⁶ /K, or a linear expansion coefficient of −4. It is an FRP using aramid fibers with x10 ^-6 /K.

A heat insulating material 22 is arranged on the outer peripheral surfaces of the thermal stress relieving material 21 and the radome ring 14 . That is, the heat insulating material 22 is wound and laminated so as to cover a region including the joint portion between the radome body portion 13 and the radome ring 14 and the entire radome ring 14 . The heat insulating material 22 is a member that reinforces the fixing structure between the shell 11 and prevents the temperature rise of the radome ring 14 . An example of the heat insulating material 22 is FRP using carbon fiber, that is, carbon fiber reinforced plastic. FRP using carbon fiber is hereinafter referred to as CFRP (Carbon Fiber Reinforced Plastics).

Next, the operation of the joint parts during flight of the projectile 1 having such a configuration will be described.

FIG. 6 is a diagram for explaining the function of the radome ring included in the flying object radome according to the embodiment. In this figure, illustration of the shell 11 is omitted. When the projectile 1 is in flight, both the radome body 13 and the radome ring 14 expand in the radial direction due to thermal expansion due to aerodynamic heating. However, since the coefficients of linear expansion are different, the thermal expansion 101 of the radome ring 14 is larger than the thermal expansion 102 of the radome main body 13 , and thermal stress is generated in the radome main body 13 . If the radome ring 14 is not provided with the slit 143 , the radome main body 13 will be destroyed by the thermal stress generated in the radome main body 13 .

On the other hand, in the present embodiment, since the slits 143 are provided in the radome ring 14 , the rigidity of the radome ring 14 is lowered compared to the case where the slits 143 are not provided in the radome ring 14 . As a result, the thermal stress generated in the radome main body 13 is alleviated, and breakage of the radome main body 13 is suppressed. By increasing the length of the slit 143 so that the closed end portion 143b of the slit 143 is located closer to the shell 11 than the rear end of the radome body 13, the radome body 13 and the The rigidity of the contacting portion of the radome ring 14 is further reduced. That is, the longer the length of the slit 143 is, the more the thermal stress acting on the radome body 13 can be relaxed.

FIG. 7 is a diagram for explaining the function of the thermal stress relaxation material in the embodiment, and is an enlarged cross-sectional view of region R in FIG. In this figure, illustration of the shell 11 is omitted. When the temperatures of the radome body 13 and the radome ring 14 are increased by aerodynamic heating, a tensile thermal stress 104 is generated due to the difference in thermal expansion between the thermal expansion 101 of the radome ring 14 and the thermal expansion 102 of the radome body 13. occurs. As shown in FIG. 6, even if the radome ring 14 is provided with the slit 143, the radome body 13 cannot withstand the thermal stress caused by the difference in thermal expansion between the radome body 13 and the radome ring 14. , the radome body 13 is damaged.

Therefore, in the present embodiment, as described above, the thermal stress relaxation member 21 is provided on the outer peripheral surface of the radome main body 13 corresponding to the fitting range of the radome ring 14 to the radome main body 13 . In such a structure, a tensile thermal stress 104 is generated in the radome body 13 due to the difference between the thermal expansion 102 of the radome body 13 and the thermal expansion 101 of the radome ring 14 . However, a compressive thermal stress 103 is generated in the radome body 13 due to the difference between the thermal expansion 105 of the thermal stress relaxation material 21 and the thermal expansion 102 of the radome body 13 . That is, the radome main body 13 corresponding to the fitting range of the radome ring 14 to the radome main body 13 is not only subjected to the tensile thermal stress 104 but also to the compressive thermal stress 103 due to the provision of the thermal stress relieving material 21. work. As a result, the radome ring 14 is subjected to a thermal stress equal to the tensile thermal stress 104 minus the compressive thermal stress 103 . This thermal stress is less than the tensile thermal stress 104 . That is, by providing the thermal stress relieving material 21, the thermal stress caused by the radome ring 14 is relieved.

If the thermal stress relieving material 21 has a negative coefficient of linear expansion, the thermal stress relieving material 21 contracts due to temperature rise. It becomes possible to suppress the thermal expansion of the body portion 13 .

FIG. 8 is a diagram for explaining the function of the heat insulating material in the embodiment, and is an enlarged cross-sectional view of region R in FIG. In this figure, illustration of the shell 11 is omitted. In the present embodiment, since the slits 143 are provided in the radome ring 14, the strength of the radome ring 14 is reduced. Therefore, the heat insulating material 22 is wound and laminated so as to cover the outer peripheral surface of the joint between the shell 11 and the radome main body 13 with the radome ring 14 interposed therebetween. At this time, by integrally molding the heat insulating material 22 from the radome ring 14 to the radome main body 13, the heat insulating material 22 can also receive the load. That is, the fixing structure for fixing the radome body 13, the radome ring 14 and the shell 11 is reinforced.

In the case where the heat insulating material 22 is CFRP called a carbonization ablator, when the heat insulating material 22 is heated at a temperature exceeding 1000° C., the resin undergoes thermal decomposition and a strong carbonized layer is formed on the surface. In addition, the base material is cooled by the endothermic reaction of gas generated during thermal decomposition. In addition, the gases generated by the pyrolysis form a boundary layer on the surface that moderates the surface temperature gradient and reduces heating of the radome ring 14 covered by the thermal insulator 22 .

With such a mechanism, a heat quantity 106 is applied from the outside to the connecting portion of the flying object 1 by aerodynamic heating, but a heat quantity 107 is transferred to the inside including the joint portion of the radome body 13, the radome ring 14, and the thermal stress relaxation material 21. can be reduced and the temperature rise of the components can be reduced.

In the embodiment, the radome ring 14 is made of a low thermal expansion alloy having a higher heat resistance temperature than FRP and a lower coefficient of linear expansion than the material forming the shell 11 . The radome ring 14 and the radome main body 13 and shell 11 are mechanically fixed by fixing parts. A thermal stress relaxation material 21 is arranged on the outer peripheral surface of the radome main body 13 near the joint with the radome ring 14 , and a heat insulating material 22 is arranged on the outer peripheral surfaces of the thermal stress relaxation material 21 and the radome ring 14 . . As a result, even if the flying object 1 is aerodynamically heated to a temperature higher than the heat-resistant temperature of the FRP, a strong connection can be realized between the shell 11 and the radome body 13 and the radome ring 14 .

Also, when the flying object 1 becomes hot due to aerodynamic heating, tensile thermal stress 104 is generated due to the difference in thermal expansion between the radome body 13 and the radome ring 14. The compressive thermal stress 103 generated in the radome body 13 due to the difference in thermal expansion between the radome body 13 and the tensile thermal stress 104 is relaxed. That is, the radome body 13 is fixed to the shell 11 by the radome ring 14 while suppressing the destruction of the radome body 13 even in a high-temperature environment due to aerodynamic heating associated with increased speed and longer flight time of the projectile. It has the effect of being able to continue.

Furthermore, since the outer peripheral surface of the joint between the shell 11 and the radome body 13 via the radome ring 14 is covered with the heat insulating material 22, the temperature of the members constituting the flying object 1 covered with the heat insulating material 22 rises. can be suppressed. In particular, when the heat insulating material 22 is CFRP called a carbonization ablator, the resin is thermally decomposed by heating by aerodynamic heating, a strong carbonized layer is formed on the surface, and the gas generated during thermal decomposition is reduced. The base material is cooled by an endothermic reaction, and a boundary layer is formed on the surface by gases generated by thermal decomposition. This reduces the heating of the portion covered with the heat insulating material 22 .

Also, a slit 143 is provided from the tip side of the radome ring 14 to the shell fitting portion 14a. As a result, the rigidity of the radome ring 14 is reduced, and the tensile thermal stress generated in the radome ring 14 due to temperature rise due to aerodynamic heating is alleviated.

Furthermore, a heat insulating material 22 is integrally molded from the radome ring 14 to the radome main body 13 . As a result, even the heat insulating material 22 can receive the load, and the strength of the radome ring 14, which has been reduced due to the provision of the slit 143, can be reinforced.

The configuration shown in the above embodiment shows an example of the content of the present invention, and it is possible to combine it with another known technology, and one configuration can be used without departing from the scope of the present invention. It is also possible to omit or change the part.

1 flying object, 11 shell, 12 flying object radome, 13 radome body, 14 radome ring, 14a shell fitting portion, 14b radome fitting portion, 21 thermal stress relaxation material, 22 heat insulating material, 31 fixing part, 111 antenna, 141, 142 through hole, 143 slit, 143a open end, 143b closed end.

Claims (8)

a radome main body that constitutes the tip of a projectile that flies toward a target by radio wave induction and that is installed on the fuselage of the projectile;
a radome ring fitted to the exterior of the fuselage and the interior of the radome main body;
a fixing component for mechanically fixing the radome ring and the radome main body;
a heat insulating material provided on the outer peripheral surface of the joint between the fuselage and the radome main body;
a thermal stress relaxation material provided on the outer peripheral surface of the radome main body corresponding to the joint with the radome ring;
A flying body radome characterized by comprising: 2. The radome for a flying object according to claim 1, wherein the radome ring has a slit extending from the front end side of the flying object to the rear end side of the flying object. 3. The flight according to claim 1, wherein the radome ring is made of an alloy material having a higher heat resistance than fiber-reinforced plastic and having a lower coefficient of linear expansion than the material forming the fuselage. A radome for the body. 4. The flying object radome according to claim 3, wherein said radome ring is made of at least one alloy material selected from the group of Invar, Super Invar and Kovar. 5. The radome for a flying object according to any one of claims 1 to 4, wherein the thermal stress relaxation material is made of a material having a coefficient of linear expansion smaller than that of the radome main body. 6. The flying object radome according to any one of claims 1 to 5, wherein the thermal stress relaxation material is made of a material having a negative coefficient of linear expansion. 7. The flying object radome according to any one of claims 1 to 6, wherein the thermal stress relaxation material is carbon fiber reinforced plastic or aramid fiber reinforced plastic. The flying object radome according to any one of claims 1 to 7 , wherein the heat insulating material is carbon fiber reinforced plastic.

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