JP2015169361A - Missile radome - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a radome attached to a tip end of a missile, capable of fixing the radome to a fuselage of the missile even if an adhesive force of an adhesive fixing the ceramic radome to a ring falls due to the excess of a temperature over a heat resistant temperature or the adhesive force falls due to the degradation of the adhesive over time.SOLUTION: A missile radome comprises: a ring 32 screwed with a screw section 8 provided to protrude from a tip end portion; and a radome 30 whose inner circumference is adhesively bonded to an outer circumference of the ring 32 and that is lower in coefficient of thermal expansion than a fuselage 50 and the ring 32, a rear end portion 31 of the radome 30 being pressed on a tip end portion of the fuselage 50, the rear end portion including a protrusion 33 protruding annularly inward, and the protrusion 33 being arranged to be interposed between end portions of the ring 32.

Description

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

  A flying object that flies by radio wave induction toward a predetermined target is provided with a radar antenna for detecting the target at the tip. The tip of the flying object is a part that is susceptible to aerodynamic loads and aerodynamic heating. For this reason, it is common for the tip of the flying body to have a pointed shape (for example, Cone, Ogive, Von_Karman shape) so as to reduce aerodynamic resistance and fly at high speed.

  In addition, since the radome needs to transmit radio waves transmitted and received by the radar antenna, a dielectric material must be used. Dielectric materials include alumina (Al2O3), cordierite (2MgO · 2Al2O3 · 5SiO2), fused silica (SiO2), silicon nitride (Si3N4) sintered ceramics, FRP (Fiber Reinforced Plastics) ) Materials are used.

  As the radome of a flying object that flies at supersonic speed, ceramic materials having a low thermal expansion coefficient (0 to 5 × 10-E6 / ° C.) excellent in heat resistance and thermal shock resistance are mainly used. In addition, the flying body is generally made of a material having high rigidity and high thermal expansion coefficient (10-30 × 10−E6 / ° C.) such as iron or aluminum. Since the aforementioned radome and the aircraft are made of different materials, there is a concern about thermal stress due to the combination. For this reason, it is common to fix the radome to the fuselage through a ring using FRP having high rigidity and a relatively low coefficient of thermal expansion, and to fix the radome and the ring with an adhesive (for example, Patent Documents). 1 and 2).

JP 2003-238929 A JP-A-10-135724

  Many flying bodies reach supersonic speeds or hypersonic speeds in a short time of several seconds from the start of flying, and the airframe is exposed to high temperatures by aerodynamic heating. The radome is one of the most severe parts of the flying body, and is subject to large aerodynamic loads, large aerodynamic heating and thermal shock. Since the radome has high strength and is required to have heat resistance and thermal shock resistance, it is common to use ceramics, which is a dielectric material having a heat resistant temperature of 1000 ° C. or more, as the radome material.

  For fixing the ceramic radome and ring, an epoxy or silicon adhesive is often used. As the radome becomes hot due to aerodynamic heating, the adhesive also gets hot. When the flying speed is increased or the flying time is increased and the total amount of aerodynamic heating is increased, there is a problem that the heat resistance temperature of the adhesive is exceeded.

  In addition, if a material with high thermal conductivity is selected to mitigate the thermal shock of the radome, heat is transferred immediately from the radome to the adhesive joint, and the temperature of the adhesive becomes high, resulting in adhesion. The heat resistance temperature of the agent may be exceeded, and the joint between the radome and the aircraft may be destroyed.

  Moreover, it has been found that the adhesive strength of the adhesive decreases due to aging. Since it is difficult to quantitatively estimate the decrease rate of the adhesive strength, there is a problem that a margin must be given to the initial adhesive strength.

  In the past, epoxy adhesives with high adhesive strength were often used, but there are few epoxy adhesives with a heat resistance temperature exceeding 200 ° C, and the heat resistance of the adhesive is increased to increase the adhesive strength of the radome. It was often difficult to raise. In addition, there is a type in which a heat insulating material is provided in the outermost shell portion of the flying body that is directly exposed to aerodynamic heating to prevent the temperature of the ring from rising. Even a radome provided with such a heat insulating material may exceed the heat resistance temperature of the adhesive.

  The present invention has been made to solve such problems, and the adhesive that fixes the radome and the ring made of ceramics has an adhesive strength that exceeds its heat-resistant temperature, or the adhesive strength decreases due to aging of the adhesive. It is an object of the present invention to obtain a structure capable of continuing to fix the radome to the flying body even when the drop is caused.

  The flying object according to the present invention includes a ring that is screw-coupled to a screw part that protrudes from a tip part of a flying object body that flies by radio wave induction toward a predetermined target, and an inner periphery of the ring. A radome having a thermal expansion coefficient smaller than that of the fuselage and the ring, the rear end of the radome being pressed against the tip of the fuselage, and the rear end protruding in an annular shape inward And the protrusion is disposed between the ends of the ring.

  According to the present invention, the radome and the ring are bonded and fixed by providing a protrusion on the inner side of the rear end of the radome and pressing the protrusion against the flying body by a ring on which a screw is formed. Even if the strength of the adhesive is reduced, the radome can be structurally fixed to the flying body.

It is sectional drawing which shows the structure of the radome for flying bodies by Embodiment 1. It is a figure which shows each axial direction of a flying body. It is a figure explaining the state which the radome for flying bodies received aerodynamic heating when a flying body flew at high speed. It is a figure showing time and speed when a flying object flies at high speed. It is a figure showing the time when the flying object flies at high speed, and the temperature of the radome for the flying object. It is a figure explaining a heat | fever being transmitted to an adhesion part by aerodynamic heating. It is the figure which showed the adhesion part temperature by the time history. It is the figure which showed the intensity | strength fall by the adhesive deterioration with age. It is sectional drawing which shows the adhesion structure of the radome of a conventional flying body radome, and a ring. It is sectional drawing which shows the structure of the radome for flying bodies by Embodiment 2. 6 is a structural diagram of a flying object radome according to Embodiment 3. FIG.

Embodiment 1 FIG.
FIG. 1 is a sectional view showing the structure of a flying object radome according to Embodiment 1 of the present invention. In FIG. 1, the flying object radome 2 is configured by bonding a radome 30 that transmits radio waves to a ring 32 at an adhesive portion 36. The radome 30 has a line-symmetric streamline shape in which the front end of the outer shell is pointed, and the outer diameter centering on the line symmetry axis of the outer shell spreads smoothly from the front end toward the rear end 31, and the rear end 31 Is open and hollow. The radome 30 is made of ceramics, for example. The ring 32 is made of, for example, FRP. The material of the ring 32 is selected so as to match the characteristics of the material used for the radome 30 and may be, for example, an aluminum alloy or a titanium alloy. The inner peripheral surface of the radome 30 and the outer peripheral surface of the ring 32 are fitted and fixed by an adhesive 5 interposed therebetween.

  The ring 32 has a threaded portion 35 formed therein. The airframe 50 of the flying body 1 has a threaded portion 8 formed therein. On the inner side of the rear end portion 31 of the radome 30, a protrusion 33 is provided on which the rear end portion of the ring 32 abuts. The protrusion 33 protrudes in an annular shape from the inside of the rear end portion 31. The protrusion 33 is formed with a contact surface for closely contacting the contact surface 34 of the body 50. A threaded portion 35 of an internal thread is formed inside the ring 32. A threaded portion 8 of a male screw is formed on the outside of the body 50. The screw portion 8 is provided at the end of the body 50. The screw portion 8 has a diameter smaller than the maximum outer periphery of the body 50 and is formed in a protruding portion protruding from the end portion. A contact surface 34 is formed at the base of the protruding portion. The screw part 35 provided on the ring 32 is screwed into the screw part 8 provided on the machine body 50, and the ring 32 is fixed to the machine body 50.

  The flying body radome 2 according to the first embodiment has a structure in which the protrusion 33 that the ring 32 is hooked is provided inside the rear end portion 31 of the radome 30, so that it comes into close contact with the contact surface 34 with the protrusion 33. In addition, the ring 32 is bonded to the radome 30. The screw portion 35 provided on the ring 32 of the radome 30 is fitted into the screw portion 8 provided on the fuselage 50, and the radome 30 is rotated so that the screw portion 35 provided on the ring 32 is coupled to the screw portion 8 provided on the fuselage 50. I will do it. The threaded portion 35 is screwed into the threaded portion 8 until a prescribed torque or axial force is generated so that both the machine body 50 and the ring 32 sandwich the protruding portion 33. The bonding strength of the bonding portion 36 may be enough to withstand this screwing load.

  FIG. 2 is a view showing each axial direction of the flying body 1. The flying body radome 2 generates only a load in the aircraft axis direction 37 to which a specified torque or axial force is applied after the ring 32 is screwed to the aircraft body 50. At this time, even if the bonding strength of the bonding portion 36 is lost, the flying body radome 2 is fixed to the flying body 1 and there is no structural problem.

  Further, since the flying object 1 flying by radio wave induction is generally low in rotation and speed in the roll direction 38, it can be fixed by the frictional force of the contact surface 34, but the radome 30 does not rotate in the roll direction 38. In this way, a detent such as a key may be provided as necessary.

  FIG. 3 is a diagram for explaining a state where the flying object radome 2 of the flying object 1 flying at high speed is subjected to aerodynamic heating. FIG. 4 is a diagram showing time and speed when the flying object 1 flies at high speed. FIG. 5 is a diagram showing the time when the flying object 1 flies at high speed and the temperature of the radome 2 for the flying object.

  When the flying object 1 flies, the speed 9 of the flying object 1 generally increases in a short time. The flying object radome 2 receives aerodynamic heating that can be expressed by the heat insulating wall temperature (Taw) 10 and the local heat transfer coefficient (α) 11 shown in FIG. Generally increases in a short time.

  FIG. 6 is a diagram for explaining that heat is transmitted to the bonding portion 36 of the flying object radome 2 by aerodynamic heating. FIG. 7 is a diagram showing the temperature of the bonded portion of the flying object radome 2 as a time history. The radome 2 for the flying object is heated by the aerodynamic heating that can be expressed by the heat insulating wall temperature (Taw) 10 and the local heat transfer coefficient (α) 11 shown in FIG. Then, the temperature 14 of the bonding portion 36 is increased. The way heat is transferred generally depends on the thermal conductivity (αR) 15 of the material of the radome 30 (for example, ceramic). If the thermal conductivity 15 is large, the heat is easily transmitted, and if it is small, the heat is not easily transmitted. As the flying body 1 increases in speed and the aerodynamic heating conditions become severe, the temperature 14 of the bonded portion rises, and the bonded portion temperature 17 exceeds the heat resistance temperature 16. Further, when the thermal conductivity (αR) 15 of the material of the radome 30 is large, the temperature 14 of the bonded portion rises in a short time and becomes the bonded portion temperature 18 exceeding the heat resistance temperature. It should be noted that the path through which heat is transmitted to the bonding portion 36 is complicated, and there is heat generation of the electronic device mounted in the flying body 1, but due to aerodynamic heating that most affects the temperature rise of the bonding portion 36. The heat transmitted from the radome 30 is described as a representative.

  FIG. 8 is a diagram showing a decrease in strength due to aging deterioration of the adhesive 5 of the flying object radome 2. It is known that the adhesive 5 deteriorates with age due to temperature, humidity, oxygen, ultraviolet rays, and the like, and generally the adhesive strength 19 is lowered. If the strength is reduced to the required strength 20 for the bonded portion 36 (a safety factor is generally taken into consideration by design), it is regarded as a life 21.

  Here, FIG. 9 is a cross-sectional view showing a bonding structure between the radome 3 and the ring 4 of the conventional flying object radome 200 shown as a comparative example. In FIG. 9, the flying object radome 200 has both a ceramic radome 3 and an FRP ring 4 bonded and fixed with an adhesive 5. Further, when the temperature of the ring 4 exceeds the heat resistance temperature due to aerodynamic heating, the heat insulating material 6 may be attached to the outer surface of the ring 4. The flying body radome 200 is fixed by a screw portion 8 provided on the flying body 1 using a screw portion 7 provided on the ring 4.

  In the conventional flying object radome 200, the temperature of the adhesive increases as the radome increases in temperature due to aerodynamic heating. When the flying speed becomes high or the flying time becomes long and the total amount of aerodynamic heating increases, the heat resistance temperature of the adhesive is exceeded. At this time, if there is no allowance for the initial adhesive strength, the joint between the radome 200 and the fuselage 50 will be destroyed. Further, when aged deterioration occurs, the adhesive strength 19 for the adhesive portion 36 exceeds the required strength 20. Here, even if other materials are healthy, the flying object radome 200 may be repaired or replaced with a new one.

  On the other hand, the flying object radome 2 according to the first embodiment is screwed onto the screw part 8 that protrudes from the tip of the flying object body 50 that flies by radio wave induction toward a predetermined target. A ring 32 coupled by a portion 35; an inner periphery of which is bonded to the outer periphery of the ring 32; and the radome 30 having a linear expansion coefficient smaller than that of the fuselage 50 and the ring 32. The rear end of the radome 30 is the fuselage 50. And the rear end portion has a projecting portion 33 projecting in an annular shape on the inner side, and the projecting portion 33 is disposed between the end portions of the ring 32. Features.

  Thus, the protrusion 33 on which the ring 32 is hooked is provided inside the rear end 31 of the flying object radome 2, and the screw part 8 provided on the flying object 1 and the screw part 35 provided on the ring 32 are coupled. It is said. As a result, even if the bonding strength 19 of the bonding portion 36 is lost, the flying object radome 2 can continue to be fixed to the flying object 1.

Embodiment 2. FIG.
FIG. 10 is a cross-sectional view showing the structure of the flying object radome 2 according to the second embodiment of the present invention. When the flying object 1 flies at high speed, the aerodynamic load 40 shown in FIG. 10 generated in the vertical axis direction 39 shown in FIG. 2 and the thermal stress 41 generated by the thermal expansion difference between different materials cause the protrusion 33 to A large stress is generated in the root portion 42.

  Therefore, the flying object radome 2 according to the second embodiment has the contact surface 34 of the radome 30 and the ring 32 provided with an inclination 43 shown in FIG. 10 in the axial direction 37 shown in FIG. The inclination 43 can prevent an increase in stress generated at the root portion 42 of the protrusion 33 and can prevent the radome 30 from being broken. Others are the same as those used in the first embodiment.

Embodiment 3 FIG.
FIG. 11 is a view showing the structure of a flying object radome 300 according to the third embodiment of the present invention. The flying object radome 300 according to the third embodiment has a structure in which the ring 32 is divided into two or more and bonded to the radome 30. In this structure, the generation of the thermal stress 41 in the circumferential direction is reduced by the different materials of the radome 30 and the ring 32.

  Thus, the thermal stress 41 can be reduced by dividing the ring 32 into two or more. Further, in the step of bonding the ring 32 to the radome 30, it becomes possible to easily bond the divided ring 32, and the others are the same as those used in the first and second embodiments.

  1 Flying object, 2 Flying object radome, 3 Radome, 4 Ring, 5 Adhesive, 6 Heat insulation material, 7 Screw part, 8 Screw part, 13 Adhesive part, 30 Radome, 31 Rear end part, 32 Ring, 33 Projection, 34 Contact surface, 35 Screw, 36 Adhesion, 42 Root, 43 Inclination, 50 Airframe, 200 Flying body radome, 300 Flying body radome.

Claims (3)

A ring that is screw-coupled to a screw part that protrudes from the tip of the airframe that flies by radio wave induction toward a predetermined target,
A radome whose inner circumference is bonded to the outer circumference of the ring, and whose linear expansion coefficient is smaller than that of the aircraft and the ring;
With
The rear end portion of the radome is pressed against the front end portion of the airframe, and the rear end portion has a protruding portion that protrudes in an annular shape inside, and the protruding portion is disposed between the end portions of the ring. A flying radome characterized by   2. A flying object radome according to claim 1, wherein the projecting portion of the radome and the contact surface of the ring are inclined.   The flying ring radome according to claim 1 or 2, wherein the ring is divided into two or more along the inner periphery of the radome.

Images