JP5303369B2 - Solid rocket motor propellant molding method - Google Patents

Description

  The present invention relates to a method for forming a solid rocket motor propellant.

  The solid rocket motor uses a solid propellant as a thrust source, and is configured to generate thrust by discharging high-temperature and high-pressure gas generated by the combustion reaction. Conventionally, as a method of forming an internal combustion type solid propellant having an inner hole (hollow part), there is a “straight type” in which the propellant is directly cast into a motor case.

  Conventionally, when a solid propellant is molded by a straight type, as shown in FIG. 1, a core 21 having a blade portion or the like corresponding to the shape of an inner hole to be formed is set in a motor case 20. Then, a slurry-like thermosetting propellant 22 is supplied into the motor case 20 from a hopper (not shown) disposed above the motor case 20, and the propellant 22 is placed in a space formed by the motor case 20 and the core 21. It was poured and heat-cured, then returned to room temperature, and the core was pulled out from the cured propellant 22 to form a solid rocket motor propellant.

  In the solid rocket motor shown in FIG. 1, relief boots 23 are provided at both ends of the motor case 20 to be bonded to the peripheral portions of both ends of the propellant 22. The relief boot 23 moves together with the heat-shrinkable propellant 22 when the thermosetting propellant 22 is returned to room temperature, so as to relieve thermal stress caused by the heat shrinkage.

  In addition, as a prior art document regarding the molding method of a solid rocket motor propellant, there exist the following patent documents 1 and 2, for example.

Japanese Patent No. 2880932 Japanese Patent No. 3138987

  In the conventional solid rocket motor propellant molding method described above, heat shrinkage occurs in the process of returning the solid propellant to room temperature. In this heat shrinkage, a force that pulls the inner portion by the outer portion of the propellant acts, and therefore stress and strain are generated on the surface of the inner hole of the solid propellant and the end portion of the solid propellant. When such stress / strain exceeds the strength range of the solid propellant, a crack occurs on the surface of the inner hole of the solid propellant. In a solid propellant, the higher the propellant filling rate, the greater the thermal strain on the inner hole surface, so that cracks are more likely to occur, and cracks are more likely to occur in the inner hole shape where stress concentration tends to occur. For this reason, there is a problem that it is difficult to mold a solid propellant having an inner hole shape with a high propellant filling rate and a large stress concentration. In addition, there is a problem that the propellant filling rate is limited by the amount of relief boots.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for molding a solid rocket motor propellant that can increase the filling rate and can eliminate or minimize the relief boot. To do.

In order to solve the above problems, the solid rocket motor propellant molding method of the present invention is characterized by comprising the following steps.
(A) The process of producing the inner side block which has a cylindrical outer peripheral surface and consists of a thermoplastic propellant.
(B) A step of casting a thermoplastic propellant in the motor case to produce a hollow cylindrical outer block having a cylindrical inner peripheral surface into which the inner block can be inserted.
(C) With the inner block inserted into the hollow portion of the outer block, the cylindrical outer peripheral surface and the cylindrical inner peripheral surface are melted and then solidified, or between the cylindrical outer peripheral surface and the cylindrical inner peripheral surface. A step of joining the inner block and the outer block by solidifying after filling the slurry-like thermoplastic propellant.

According to the present invention described above, since the propellant is divided into an inner block and an outer block and molded separately and then joined together, the thermal stress / strain generated in the inner hole can be greatly reduced. This is because the propellant molding is performed for each block, so that the inner hole strain is the same as when the solid propellant filling rate is lowered or the solid propellant is molded in a small motor case. is there. Therefore, according to this invention, the filling rate of a propellant can be raised.
Further, since the distortion is greatly reduced, the relief boot can be unnecessary or minimized.
Moreover, since the thermoplastic propellant is used as a bonding agent for bonding the inner block and the outer block, both can be firmly bonded.

  Another feature of the solid rocket motor propellant molding method is that in the step (c), a heating ring heated to a temperature equal to or higher than the melting point of the thermoplastic propellant is used as the cylindrical inner peripheral surface and the cylindrical outer peripheral surface. The cylindrical outer peripheral surface and the cylindrical inner peripheral surface are melted by moving in the axial direction between the surfaces and then solidified.

  When the gap formed between the inner block and the outer block is sufficiently small, the joining surface can be easily formed between the cylindrical inner peripheral surface and the cylindrical outer peripheral surface by moving the heating ring in the axial direction as described above. Can be formed.

  Another feature of the solid rocket motor propellant molding method is that in the step (c), the cylindrical outer peripheral surface and the cylindrical inner peripheral surface from a heating ring heated to a temperature equal to or higher than the melting point of the thermoplastic propellant. And extruding a slurry-like thermoplastic propellant between the cylindrical outer peripheral surface and the cylindrical inner peripheral surface by moving the heating ring in the axial direction between the cylindrical inner peripheral surface and the cylindrical outer peripheral surface. It is filling a slurry-like thermoplastic propellant between the surfaces.

  When the gap formed between the inner block and the outer block is wide, the cylindrical inner peripheral surface and the cylinder can be obtained by extruding the slurry-like thermoplastic propellant from the heating ring and moving the heating ring in the axial direction as described above. A joining surface can be easily formed in the whole between outer peripheral surfaces.

  Another feature of the solid rocket motor propellant molding method is that in the step (c), a liquid heated to a temperature higher than the melting point of the thermoplastic propellant is flowed into the heating ring. Heating the heating ring.

  Thus, the heating ring can be easily heated by flowing the heated liquid through the heating ring.

  Further, another feature of the method for forming the solid rocket motor propellant is that a supply pipe for supplying the liquid to the heating ring and a discharge pipe for discharging the liquid from the heating ring include an axis of the heating ring. It is connected to one end side in the direction, and in the step (c), the heating ring is moved in the axial direction by pulling out the supply pipe and the discharge pipe in the axial direction.

  Since the heating ring is moved in the axial direction by pulling out the supply pipe and the discharge pipe in this way, the heating ring can be easily moved in the axial direction.

  According to the solid rocket motor propellant molding method of the present invention, the filling rate can be increased and the relief boot can be made unnecessary or minimized.

It is a figure explaining the shaping | molding method of the conventional solid rocket motor propellant. It is a figure explaining manufacture of an inner side block in 1st Embodiment of the shaping | molding method of the solid rocket motor propellant which concerns on this invention. It is a figure explaining manufacture of an outside block in a 1st embodiment of a molding method of a solid rocket motor propellant concerning the present invention. In 1st Embodiment of the shaping | molding method of the solid rocket motor propellant which concerns on this invention, it is a figure explaining joining of an inner side block and an outer side block. It is a figure which shows the structure of the heating ring used in 1st Embodiment of the shaping | molding method of the solid rocket motor propellant which concerns on this invention. It is a figure explaining 2nd Embodiment of the shaping | molding method of the solid rocket motor propellant which concerns on this invention. It is a figure which shows the cross-section of the heating ring used in 2nd Embodiment of the shaping | molding method of the solid rocket motor propellant which concerns on this invention. It is a figure explaining 3rd Embodiment of the shaping | molding method of the solid rocket motor propellant which concerns on this invention. It is a figure explaining 4th Embodiment of the shaping | molding method of the solid rocket motor propellant which concerns on this invention. It is a figure explaining 5th Embodiment of the shaping | molding method of the solid rocket motor propellant which concerns on this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

  The outline of the first embodiment of the solid rocket motor propellant molding method according to the present invention is that an inner block and an outer block made of a thermoplastic propellant are separately manufactured, and both are joined using a heating ring. is there. Hereinafter, the first embodiment will be specifically described with reference to FIGS.

FIG. 2 is a diagram for explaining the production of the inner block 5 in the first embodiment of the solid rocket motor propellant molding method according to the present invention.
As shown in FIG. 2A, a core 4 having a shape corresponding to the shape of the inner hole 5b to be formed is arranged inside a hollow cylindrical case 3 whose bottom is closed. The thermoplastic propellant 2 that has been softened and slurried is poured into the space formed therebetween. When the thermoplastic propellant 2 is cooled and solidified, the core 4 is pulled out from the propellant. Thereby, as shown in FIG. 2B, the inner block 5 having the cylindrical outer peripheral surface 5a and made of the thermoplastic propellant is manufactured.

  In the conventional method for forming a propellant, a thermosetting propellant was used. However, in the present invention, it is solid at a use temperature near normal temperature (for example, 20 ° C.), but it is high (for example, 50 to 60 ° C. or higher). Use a thermoplastic propellant that melts when heated. From the viewpoint of manufacturability and safety of the solid rocket motor, the melting point of the thermoplastic propellant used in the present invention is preferably 100 ° C. or less.

Such thermoplastic propellants include, for example, those composed of a binder containing a thermoplastic material, ammonium perchlorate and aluminum. The composition ratio in this case may be, for example, a binder of 16 to 20% by weight, ammonium perchlorate of 66 to 80%, and aluminum of 0 to 18%.
The binder is made of, for example, butadiene elastomer, liquid butadiene, a plasticizer, and a fluidizing agent. In this case, the composition ratio in the binder may be, for example, 20 to 30 wt% butadiene elastomer, 0 to 20 wt% liquid butadiene, 50 to 75 wt% plasticizer, and 5 wt% fluidizing agent.
The thermoplastic propellant that can be used in the present invention is not limited to the above-described composition, and may be other thermoplastic propellants having appropriate flammability and mechanical properties as a propellant. .

FIG. 3 is a diagram for explaining the production of the outer block 6 in the first embodiment of the solid rocket motor propellant molding method according to the present invention.
As shown in FIG. 3, a thermoplastic propellant is cast into the motor case 7 to produce a hollow cylindrical outer block 6 having a cylindrical inner peripheral surface 6a into which the inner block 5 can be inserted. In order to form the hollow portion of the outer block 6, a core (not shown) is used when casting the thermoplastic propellant. In consideration of thermal shrinkage during cooling, a core having an outer diameter slightly smaller than the outer diameter of the inner block 5 after cooling and solidification is used. Thereby, the outer block 6 is manufactured so that the inner diameter of the outer block 6 after cooling and solidification is slightly larger than the outer diameter of the inner block 5.

  Either of the inner block 5 and the outer block 6 may be manufactured in parallel or in any order.

FIG. 4 is a view for explaining the joining of the inner block 5 and the outer block 6 in the first embodiment of the solid rocket motor propellant molding method according to the present invention.
As shown in FIG. 4, the inner block 5 is inserted into the hollow portion of the outer block 6. In this state, the inner block 5 and the outer block 6 are joined by melting and solidifying the cylindrical outer peripheral surface 5a and the cylindrical inner peripheral surface 6a.

In order to melt the cylindrical outer peripheral surface 5a and the cylindrical inner peripheral surface 6a, a heating ring 10A is used in the present invention. Here, FIG. 5 is a diagram showing a configuration of the heating ring 10A used in the first embodiment of the present invention. 5B is a cross-sectional view taken along line 5B-5B in FIG. 5A.
The heating ring 10 shown in FIG. 5 is made of a material having good thermal conductivity (for example, copper, aluminum, etc.), and has an annular flow for flowing a heating liquid (for example, hot water) 13 heated to a melting point of a thermoplastic propellant. A passage 10a is provided inside. As the heating liquid 13, for example, hot water heated to a temperature higher than the melting point of the thermoplastic propellant (for example, 70 ° C. to 100 ° C.) can be used.

A supply pipe 11 for supplying the heating liquid 13 to the heating ring 10 and a discharge pipe 12 for discharging the heating liquid 13 from the heating ring 10 are on one end side in the axial direction of the heating ring 10 (FIG. 5A). At the bottom). The supply pipe 11 and the discharge pipe 12 extend in parallel with the axial center of the heating ring 10 and have flow paths 11a and 12a for flowing the heating liquid 13 therein. The supply pipe 11 and the discharge pipe 12 are preferably made of a material having a low thermal conductivity (for example, a plastic material such as FRP).
Hereinafter, what connected the supply pipe | tube 11 and the discharge pipe 12 to the heating ring 10A is called the heating apparatus 9. FIG.

  As shown in FIG. 5B, the cross section of the heating ring 10 </ b> A has a “drop shape” in which one end (lower end in this figure) side in the axial direction has a gentle roundness and the other end (upper end in this figure) side is tapered. The heating ring 10A is connected to the supply pipe 11 and the discharge pipe 12 on the rounded side.

  To join the inner block 5 and the outer block 6, as shown in FIG. 4B, a heating ring 10 </ b> A is attached to the end faces of the inner block 5 and the outer block 6 in accordance with the planned joining positions of the inner block 5 and the outer block 6. Deploy.

  Since the supply pipe 11 and the discharge pipe 12 are connected to the heating ring 10A, the outer peripheral surface of the inner block 5 and the outer block 6 are formed so that holes for inserting the supply pipe 11 and the discharge pipe 12 are formed. Grooves are formed in advance on the inner peripheral surface, and the heating device 9 is arranged by inserting the supply pipe 11 and the discharge pipe 12 between the inner block 5 and the outer block 6 as shown in FIG. 5B.

  Then, while supplying the heating liquid 13 heated to a temperature equal to or higher than the melting point of the thermoplastic propellant to the heating ring 10, the supply pipe 11 and the discharge pipe 12 are pulled out in the direction opposite to the heating ring 10, as shown in FIG. 4C. Next, the heating device 9 is moved in the axial direction. Then, the outer peripheral surface of the inner block 5 and the inner peripheral surface of the outer block 6 melt in contact with the heating ring 10A in the course of the heating ring 10A moving in the axial direction, and then solidify due to a decrease in temperature. Therefore, by moving the heating ring 10 </ b> A to the opposite end surfaces of the inner block 5 and the outer block 6, the entire cylindrical outer peripheral surface 5 a and the cylindrical inner peripheral surface 6 a can be joined.

  According to the first embodiment of the present invention described above, since the propellant is divided into the inner block 5 and the outer block 6 and molded separately, the two are joined together, so the thermal stress / strain generated in the inner hole is greatly reduced. it can. This is because the propellant molding is performed for each block, so that the inner hole strain is the same as when the solid propellant filling rate is lowered or the solid propellant is molded in a small motor case. is there. Therefore, according to this invention, the filling rate of a propellant can be raised.

Since the distortion is greatly reduced, the relief boot can be unnecessary or minimized.
Since the thermoplastic propellant is used as a bonding agent for bonding the inner block 5 and the outer block 6, both can be firmly bonded.

  When the gap formed between the inner block 5 and the outer block 6 is sufficiently small, the entire area between the cylindrical inner peripheral surface 6a and the cylindrical outer peripheral surface 5a is moved by moving the heating ring 10A in the axial direction as described above. In addition, the joint surface can be easily formed.

By flowing the heated liquid through the heating ring 10A, the heating ring 10A can be easily heated.
Since the heating ring 10A is moved in the axial direction by pulling out the supply pipe 11 and the discharge pipe 12, the heating ring 10A can be easily moved in the axial direction.

  In the example of FIG. 4, the heating device 9 is moved downward in a state where the heating ring 10 </ b> A is located at the upper end of the heating device 9, but conversely, the heating ring 10 </ b> A is lower than the lower end of the heating device 9. The heating device 9 may be moved upward in a state of being positioned at the position. The same applies to other embodiments described below.

  In the example of FIG. 4, the axial direction of the motor case 7 is oriented vertically, but the axial direction of the motor case 7 may be directed horizontally or inclined with respect to the horizontal. In this case, the supply pipe 11 and the discharge pipe 12 are pulled out in the direction opposite to the heating ring 10A, and the heating device 9 is moved in the axial direction. The same applies to other embodiments described below.

  FIG. 6 is a diagram for explaining a second embodiment of the solid rocket motor propellant molding method according to the present invention. 2nd Embodiment of this invention is suitable when the clearance gap formed between the inner side block 5 and the outer side block 6 is wide, and uses the heating ring 10B of the structure shown to FIG. 6A.

  Here, FIG. 7A is a sectional view taken along line 7A-7A in FIG. 6A. As shown in FIG. 7A, the heating ring 10B has a flow path 10a for flowing a heating liquid heated to a temperature equal to or higher than the melting point of the thermoplastic propellant, similarly to the heating ring 10A in the first embodiment. doing.

  As shown in FIG. 6A, a supply pipe 11 for supplying the heating liquid 13 to the heating ring 10B and a discharge pipe 12 for discharging the heating liquid 13 from the heating ring 10B are provided on the shaft of the heating ring 10B. It is connected to one end side in the direction (lower side in FIG. 6A). The supply pipe 11 and the discharge pipe 12 are preferably made of a material having a low thermal conductivity (for example, a plastic material such as FRP).

  Here, FIG. 7B is a cross-sectional view taken along line 7B-7B in FIG. 6A. As shown in FIG. 7B, a propellant supply pipe 15 for supplying slurry-like thermoplastic propellant to the heating ring 10 </ b> B is disposed inside the heated liquid supply pipe 11. Inside the propellant supply pipe 15, a flow path 16 for flowing the slurry-like thermoplastic propellant 14 is formed. A similar propellant supply pipe 15 is also arranged inside the heated liquid discharge pipe 12. With this configuration, the heating ring 10B extrudes the slurry-like thermoplastic propellant 14 from the side opposite to the side where the supply pipe 11 and the discharge pipe 12 are connected.

  In the second embodiment, in order to join the inner block 5 and the outer block 6, a heating ring 10 </ b> B is disposed between the inner block 5 and the outer block 6 as shown in FIG. 6B. And while supplying the heating liquid 13 heated to the temperature more than melting | fusing point of a thermoplastic propellant to the heating ring 10B, between the heated heating ring 10B and the inner block 5 and the outer block 6, it is slurry-like thermoplasticity. While pushing out the propellant 14, the supply pipe 11 and the discharge pipe 12 are pulled out in the direction opposite to the heating ring 10, and the heating ring 10B is moved in the axial direction (downward in FIG. 6).

As a result, the entire space between the inner block 5 and the outer block 6 is filled with the slurry-like thermoplastic propellant 14. When the temperature of the thermoplastic propellant 14 filled between the inner block 5 and the outer block 6 is lowered and solidified, the inner block 5 and the outer block 6 are joined.
When the thermoplastic propellant 14 is filled in the axial end portion (the portion where filling is started) between the inner block 5 and the outer block 6, the end face is closed with the lid member 17 as shown in FIG. 6B. As a result, the thermoplastic propellant 14 can be prevented from flowing out of the end face, and can be filled efficiently.

  According to the second embodiment described above, when the gap formed between the inner block 5 and the outer block 6 is wide, the slurry-like thermoplastic propellant 14 is extruded from the heating ring 10B as described above and the heating ring 10B. Is moved in the axial direction, a joining surface can be easily formed on the entire surface between the cylindrical inner peripheral surface 6a and the cylindrical outer peripheral surface 5a.

  Further, in the process in which the heating ring 10B moves between the inner block 5 and the outer block 6 in the axial direction, the portion of the inner block 5 and the outer block 6 where the heating ring 10B contacts is melted by the heat and melted. Since the slurry-like thermoplastic propellant extruded from the heating ring 10B comes into contact with the portion, the inner block 5 and the outer block 6 can be firmly joined by solidifying the slurry.

  As another effect of the second embodiment, as in the first embodiment, the propellant is divided into the inner block 5 and the outer block 6 and then molded separately, and the two are joined together. The strain can be greatly reduced, the propellant filling rate can be increased, and the relief boot can be unnecessary or minimized.

FIG. 8 is a diagram for explaining a third embodiment of the method for molding a solid rocket motor propellant according to the present invention.
3rd Embodiment of this invention is suitable when the clearance gap formed between the inner side block 5 and the outer side block 6 is small, and uses the heating ring 10C of the structure shown to FIG. 8A.

  The heating ring 10 </ b> C has a heater 18 disposed therein, and a cable 20 that supplies power to the heater 18 is connected to one end in the axial direction (lower end in FIG. 8A). A rod 21 for moving the heating ring 10C in the axial direction is connected to one end side in the axial direction of the heating ring 10C. The rod 21 has a hollow portion, and the cable 20 is passed through the hollow portion.

  Further, temperature sensors 19a and 19b for detecting the temperature of the surface of the heating ring 10C (in the illustrated example, the inner peripheral surface side and the outer peripheral surface side) are arranged near the inner surface of the heating ring 10C. Although not shown, a signal line for transmitting detection signals of the temperature sensors 19 a and 19 b is passed through the rod 21.

In 3rd Embodiment, in order to join the inner side block 5 and the outer side block 6, as shown to FIG. 8B, the heating ring 10C heated to the temperature more than melting | fusing point of a thermoplastic propellant is used for the inner side block 5 and the outer side block. 6 is moved in the axial direction. That is, the heating ring 10 </ b> C is moved in the axial direction by pulling out the rod in the direction opposite to the heating ring 10. Thereby, the cylindrical outer peripheral surface 5a of the inner block 5 and the cylindrical inner peripheral surface 6a of the outer block 6 are melted and then solidified.
In this case, the temperature sensor 19a, 19b detects the surface temperature of the heating ring 10C, and the current can be controlled so that the temperature does not rise too much, so that bonding can be performed safely.

  According to the above-described third embodiment, as in the first embodiment, the propellant is divided into the inner block 5 and the outer block 6 and molded separately, and the two are joined together. Strain can be greatly reduced, the propellant filling rate can be increased, and relief boots can be unnecessary or minimized.

FIG. 9 is a view for explaining a fourth embodiment of the solid rocket motor propellant molding method according to the present invention.
In the fourth embodiment, blocks made of three or more thermoplastic propellants are joined to form a solid rocket motor propellant. That is, the inner block 5 is composed of a plurality of small blocks divided in the radial direction.

In FIG. 9, it is assumed that the inner block 5 is composed of two small blocks 5A and 5B, and a total of three blocks are joined together with the outer block 6 to form a solid rocket motor propellant.
First, two small blocks 5A and 5B and an outer block 6 are manufactured. The two small blocks 5A and 5B are cast with a thermoplastic propellant using a cylindrical case and a core corresponding to the size of the small block to be molded, as in the method described in FIG. Can be produced.

  As shown in FIGS. 9A to 9C, the outer block 6 and the small block 5B are joined, and the small blocks 5A and 5B are joined together. This joining may be performed using any of the heating rings 10A to 10C in the first to third embodiments described above. In addition, after joining small block 5A, 5B and shape | molding the integral inner block 5, you may join this inner block 5 and the outer block 6. FIG.

  According to the fourth embodiment of the present invention, since the thickness of each block constituting the inner block 5 and the outer block 6 can be reduced as compared with the first to third embodiments described above, the inner hole It is possible to further reduce the thermal stress / strain generated in.

FIG. 10 is a diagram for explaining a fifth embodiment of the solid rocket motor propellant molding method according to the present invention.
In the first to fourth embodiments described above, the inner block 5 having an inner hole is manufactured and joined to the outer block 6. However, in the fifth embodiment of the present invention, the inner block 5 having no inner hole is formed. Fabricate and join this to the outer block 6. This joining may be performed by the same method as in each of the embodiments described above.

  When the inner block 5 and the outer block 6 are joined, the core 23 heated to the melting point of the thermoplastic propellant or higher is pushed in the axial direction from the end face of the propellant joined by the two blocks, and has a predetermined cross-sectional shape. An inner hole is formed. The core 23 has, for example, a cross shape or a star shape in cross section.

In the configuration example of FIG. 10, the core 23 is formed of a metal with good thermal conductivity (aluminum, copper, etc.), and a flow path 23 a for flowing the heating fluid 26 is formed inside the core 23. . The heating fluid 26 is supplied to the core via the supply pipe 24 and is discharged via the discharge pipe 25.
As the heating fluid 26, for example, hot water heated to a temperature higher than the melting point of the thermoplastic propellant (for example, 70 ° C. to 100 ° C.) can be used.
As a configuration for heating the core 23, a configuration in which an electric heater is incorporated in the core 23 may be employed.

  Although the embodiments and examples of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is the embodiments of these inventions. It is not limited to. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

2 Thermoplastic propellant 3 Case 4 Core 5 Inner block 5a Cylinder outer peripheral surface 5b Inner hole 6 Outer block 6a Cylinder inner peripheral surface 7 Motor case 9 Heating device 10A, 10B, 10C Heating ring 10a Flow path 11 Supply pipe 11a Flow path 12 Discharge pipe 12a Flow path 13 Heating fluid 14 Slurry thermoplastic propellant 15 Propellant supply pipe 16 Flow path 17 Lid member 18 Heater 19a, 19b Temperature sensor 20 Cable 21 Rod 23 Core 23a Flow path 24 Supply pipe 25 Discharge pipe 26 Heating fluid

Claims (5)

(A) An inner block made of a thermoplastic propellant having a cylindrical outer peripheral surface is produced,
(B) Casting a thermoplastic propellant in the motor case to produce a hollow cylindrical outer block having a cylindrical inner peripheral surface into which the inner block can be inserted;
(C) With the inner block inserted into the hollow portion of the outer block, the cylindrical outer peripheral surface and the cylindrical inner peripheral surface are melted and then solidified, or between the cylindrical outer peripheral surface and the cylindrical inner peripheral surface. A method for forming a solid rocket motor propellant, characterized in that an inner block and an outer block are joined by solidifying after filling a slurry-like thermoplastic propellant.   In the step (c), the heating ring heated to a temperature equal to or higher than the melting point of the thermoplastic propellant is moved axially between the cylindrical inner peripheral surface and the cylindrical outer peripheral surface to The solid rocket motor propellant molding method according to claim 1, wherein the cylindrical inner peripheral surface is melted and then solidified.   In the step (c), while extruding a slurry-like thermoplastic propellant between the cylindrical outer peripheral surface and the cylindrical inner peripheral surface from a heating ring heated to a temperature equal to or higher than the melting point of the thermoplastic propellant, A slurry-like thermoplastic propellant is filled between the cylindrical outer peripheral surface and the cylindrical inner peripheral surface by moving the heating ring in the axial direction between the cylindrical inner peripheral surface and the cylindrical outer peripheral surface. A method for forming a solid rocket motor propellant according to claim 1.   The solid rocket motor according to claim 2 or 3, wherein in the step (c), the heating ring is heated by flowing a liquid heated to a temperature higher than the melting point of the thermoplastic propellant into the heating ring. Propellant molding method. A supply pipe for supplying the liquid to the heating ring and a discharge pipe for discharging the liquid from the heating ring are connected to one end side in the axial direction of the heating ring,
5. The method for forming a solid rocket motor propellant according to claim 4, wherein in the step (c), the heating ring is moved in the axial direction by pulling out the supply pipe and the discharge pipe in the axial direction.

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