Gas generator and underwater launcher

Abstract

To provide a gas generator that can easily accommodate changes in the specifications of a projectile. [Solution] According to one embodiment, a gas generator 3 used in an underwater launcher 1 for launching a projectile underwater includes a plurality of modules 4. Each module 4 includes a plurality of parallel columnar propellant grains 6 and a cylindrical case 5 that houses the propellant grains 6. With this configuration, if the combustion gas characteristics of one module 4 are known, when the specifications of the projectile are changed, the combustion gas characteristics of the gas generator 3 can be determined simply by changing the number of modules 4.

Description

Technical Field

[0001] The present disclosure relates to a gas generator used in an underwater launching apparatus that launches a projectile underwater, and an underwater launching apparatus including the gas generator.

Background Art

[0002] Conventionally, gas generators used in underwater launching apparatuses that launch projectiles underwater are known. For example, Patent Document 1 discloses a gas generator provided at the bottom of a storage container that accommodates a projectile. In Patent Document 1, the projectile is referred to as "flying object", and the storage container is referred to as "launching tube".

[0003] More specifically, the gas generator of Patent Document 1 includes a combustion chamber that communicates with the interior of the storage container through a nozzle formed at the bottom of the storage container, and a propellant that is a gunpowder accommodated in the combustion chamber. When the propellant is ignited, combustion gas is ejected into the storage container through the nozzle.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the gas generator of Patent Document 1, when various specifications such as the mass of the projectile are changed, the gas generator is newly designed in accordance with the changed specifications, and a combustion gas characteristic test or the like is performed on the newly designed gas generator.

[0006] Accordingly, an object of the present disclosure is to provide a gas generator that can easily respond to changes in the specifications of a projectile, and an underwater launching apparatus including the gas generator.

Means for Solving the Problems

[0007] In one aspect, this disclosure provides a gas generator for use in an underwater launcher that launches a projectile underwater, comprising a plurality of modules, each of which includes a plurality of columnar propellant grains parallel to each other and a cylindrical case housing the plurality of propellant grains.

[0008] This disclosure also provides an underwater launching device comprising a bottomed cylindrical containment vessel for storing a projectile, a gas generator provided at the bottom of the containment vessel, and a control device for controlling the plurality of ignition devices of the gas generator, wherein the control device divides the plurality of ignition devices into a plurality of groups and activates each group sequentially. [Effects of the Invention]

[0009] The present disclosure provides a gas generator that can easily accommodate changes in the specifications of a projectile, and an underwater launcher including the gas generator. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an underwater launching device including a gas generator according to one embodiment. [Figure 2] This is an enlarged cross-sectional view of the main part of Figure 1. [Figure 3] This is a cross-sectional view along line III-III in Figure 2. [Figure 4] This graph shows the change in combustion gas mass flow rate over time. [Modes for carrying out the invention]

[0011] Figure 1 shows an underwater launcher 1 including a gas generator 3 according to one embodiment. The underwater launcher 1 launches a projectile 10 underwater and includes a containment vessel 2 and a control device 9 in addition to the gas generator 3. The launch direction of the projectile 10 may be upward or sideways.

[0012] The projectile 10 has a roughly cylindrical shape. The containment vessel 2 is a bottomed container that houses the projectile 10. The axial direction of the containment vessel 2 is the launch direction of the projectile 10. Specifically, the containment vessel 2 has a circumferential wall 21 with an inner diameter larger than the diameter of the projectile 10, and a bottom 22 that closes one of a pair of openings formed by the circumferential wall 21.

[0013] In this embodiment, the tip of the projectile 10 protrudes from the containment vessel 2, and a ring 23 is provided at the end of the peripheral wall 21 opposite the bottom 22 to close the gap between the peripheral wall 21 and the projectile 10. In this embodiment, a cover 24 that covers the tip of the projectile 10 is attached to the containment vessel 2, and the projectile 10 is launched by piercing through the cover 24. The inside of the containment vessel 2 is pressurized with air to a pressure approximately the same as the water pressure outside the containment vessel 2.

[0014] The gas generator 3 is located at the bottom 22 of the containment vessel 2. In this embodiment, the gas generator 3 is positioned between the bottom 22 and the projectile 10.

[0015] As shown in Figures 2 and 3, the gas generator 3 includes a plurality of cylindrical modules 4. All modules 4 have the same structure. In this embodiment, as shown in Figure 2, the modules 4 are arranged in multiple stages (four stages in the illustrated example) along the axial direction of the module 4.

[0016] Furthermore, in this embodiment, the modules 4 are arranged horizontally in each of the multiple rows, as shown in Figure 3. In the example shown, there are three modules 4 in each row, but the number of modules 4 in each row is not limited to this and can be changed as appropriate. For example, there may be seven modules 4 in each row, such that six modules 4 surround one module 4.

[0017] In other words, in this embodiment, multiple module rows, each consisting of multiple modules 4 arranged coaxially, are formed around the centerline of the gas generator 3.

[0018] As shown in Figure 3, each module 4 includes a plurality of cylindrical propellant grains 6 that extend in the axial direction of the module 4 and are parallel to each other, and a cylindrical case 5 that accommodates the propellant grains 6 and extends in the axial direction of the module 4. That is, the axial direction of the module 4 is also the axial direction of the case 5.

[0019] In the present embodiment, in each module row, the cases 5 of all the modules 4 are connected to each other to form a continuous pipe. Further, in the present embodiment, the continuous pipes are connected to each other by a bent plate 31 that forms a cylindrical shape centered on the center line of the gas generator 3.

[0020] Each propellant grain 6 includes a hollow cylindrical core made of explosive, which has a central hole into which a fuse is inserted, and a cover made of non-combustible material that covers the outer peripheral surface of the core. The propellant grain 6 is ignited inside the central hole, and the ignition causes the core to burn radially outward from the central hole.

[0021] The case 5 of each module 4 is provided with a plurality of through holes 51 arranged in the circumferential direction and the axial direction.

[0022] Further, in the present embodiment, the same number of ignition device units 80 as the aforementioned module rows are arranged between the module 4 closest to the bottom 22 of the storage container 2 and the bottom 22, and a hood 7 is arranged between all the modules 4 and the projectile 10.

[0023] In the present embodiment, in each module row, a duct 52 whose diameter decreases as the distance from the case 5 increases is joined to the case 5 of the module 4 located farthest from the bottom 22 of the storage container 2.

[0024] The hood 7 includes an umbrella portion 71 having an inclined ceiling wall that reduces in diameter toward the center, to which all the ducts 52 are joined, and a throat portion 72 joined to the center of the umbrella portion 71. With such a configuration, the hood 7 merges the combustion gases ejected from all the modules 4 and ejects the merged gas from the throat portion 72.

[0025] Each ignition unit 80 includes multiple ignition devices 8, each igniting a propellant grain 6 in all modules 4 on the corresponding module row. In other words, the number of ignition devices 8 in each ignition unit 80 is equal to the product of the number of modules 4 on the module row and the number of propellant grains 6 in each module 4. Furthermore, the total number of ignition devices 8 in all ignition units 80 is equal to the product of the total number of modules 4 and the number of propellant grains 6 in each module 4.

[0026] In the gas generator 3 described above, if the combustion gas characteristics of one module 4 are known, then when the specifications of the projectile 10 are changed, the combustion gas characteristics of the gas generator 3 can be determined simply by changing the number of modules 4. In other words, there is no need to conduct new combustion gas characteristic tests. Therefore, it is possible to easily respond to changes in the specifications of the projectile 10. This makes it possible to reduce the costs and lead times associated with changes in the specifications of the projectile 10.

[0027] Furthermore, in this embodiment, since through holes 51 are provided in the case 5 of each module 4 so as to be aligned in the circumferential and axial directions, it is also possible to eject combustion gas from the module 4 in the lateral direction.

[0028] Furthermore, in this embodiment, since the modules 4 are arranged side by side in each of the multiple stages, when there are constraints on the installation space of the gas generator 3, it is possible to determine the optimal arrangement of the modules 4 in the axial direction of the modules 4 and in the direction perpendicular to the axial direction in order to secure the total amount of propellant grains 6.

[0029] The control device 9 of the underwater launcher 1 controls all the ignition devices 8 of the gas generator 3. The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, dedicated processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor.

[0030] The control device 9 divides all the ignition devices 8 into multiple groups and activates each group sequentially. The method of dividing into groups is not particularly limited, but for example, groups may be formed for each stage of module 4. That is, the ignition devices 8 corresponding to all the propellant grains 6 of the nth stage of the three modules 4 may be the nth group. In this case, the control device may activate the ignition devices 8 in order, for example, starting with the group closest to the projectile 10.

[0031] Alternatively, grouping may be performed for each module column. Furthermore, grouping may be performed using a number less than the number of propellant grains 6 contained in each module 4.

[0032] As described above, if all ignition devices 8 are activated sequentially for each group, the combustion gas mass flow rate ejected from the gas generator 3 can be gradually increased, as shown in Figure 4, in accordance with the increase in volume between the projectile 10 and the bottom 22 of the containment vessel 2 as the projectile 10 exits the containment vessel 2. This makes it possible to maintain the thrust, i.e., acceleration, of the projectile 10.

[0033] <Variation> This disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the gist of this disclosure.

[0034] For example, the hood 7 is optional. However, if the hood 7 is present as in the above embodiment, the ejection velocity of the combustion gas from the gas generator 3 can be increased.

[0035] Furthermore, the gas generator 3 does not necessarily have to be positioned between the bottom 22 of the containment vessel 2 and the projectile 10. Similar to the gas generator in Patent Document 1, a nozzle may be formed in the bottom 22 of the containment vessel 2, and the gas generator may be positioned outside the containment vessel 2. In this case, the gas generator may include a chamber that covers the nozzle from the outside, and a plurality of modules 4 may be housed within the chamber.

[0036] Furthermore, the modules 4 do not necessarily need to be arranged in multiple stages along their axial direction; they may be arranged in a single stage side-by-side. However, if the modules 4 are arranged in multiple stages along their axial direction as in the embodiment described above, the ignition timing of the propellant grains 6 can be made different along the axial direction of the modules 4. When the modules 4 are arranged in multiple stages along the axial direction, the number of modules 4 in each stage may be one.

[0037] <Summary> In a first aspect, the present disclosure provides a gas generator for use in an underwater launching device for launching a projectile underwater, comprising a plurality of modules, each including a plurality of columnar propellant grains parallel to each other and a cylindrical case for housing the plurality of propellant grains.

[0038] With the above configuration, by understanding the combustion gas characteristics of one module, if the specifications of the projectile are changed, the combustion gas characteristics of the gas generator can be determined simply by changing the number of modules. In other words, there is no need to conduct new combustion gas characteristic tests. Therefore, it is possible to easily respond to changes in the specifications of the projectile. This makes it possible to reduce the costs and lead times associated with changes in the specifications of the projectile.

[0039] In a second embodiment, in the first embodiment, the plurality of modules may be arranged in multiple stages in the axial direction of the case. With this configuration, the ignition timing of the propellant grains can be made different in the axial direction of the case.

[0040] In a third embodiment, in the second embodiment, the plurality of modules may be arranged side by side in each of the plurality of stages. With this configuration, when there are constraints on the installation space of the gas generator, it is possible to determine the optimal arrangement of modules in the axial direction of the case and in a direction perpendicular to the axial direction in order to secure the total amount of propellant grains.

[0041] In a fourth embodiment, in the third embodiment, the gas generator may further include a hood positioned between the plurality of modules and the projectile, which combines the combustion gases ejected from the plurality of modules and ejects them from the throat. This configuration makes it possible to increase the ejection velocity of the combustion gases from the gas generator.

[0042] In a fifth embodiment, in any of the first to fourth embodiments, the case may be provided with a plurality of through holes arranged in the circumferential and axial directions. This configuration allows for the lateral ejection of combustion gas from the module.

[0043] In a sixth embodiment, in any of the first to fifth embodiments, for example, the gas generator may further include a plurality of ignition devices for igniting the plurality of propellant grains of the plurality of modules, respectively.

[0044] In a seventh aspect, the present disclosure provides an underwater launcher comprising a bottomed cylindrical containment vessel for storing a projectile, a gas generator according to a sixth aspect provided at the bottom of the containment vessel, and a control device for controlling the plurality of ignition devices of the gas generator, wherein the control device divides the plurality of ignition devices into a plurality of groups and activates each group sequentially.

[0045] With the above configuration, the mass flow rate of combustion gas ejected from the gas generator can be gradually increased in accordance with the increase in volume between the projectile and the bottom of the containment vessel as the projectile exits the containment vessel. This allows the thrust, i.e., acceleration of the projectile to be maintained. [Explanation of Symbols]

[0046] 1. Underwater launcher 10 projectiles 2 Containment vessel 22 bottom 3. Gas Generator 4 modules 5 cases 51 Through hole 6. Propellant grains 7 Food 72 Throat 8 Ignition device 9 Control device

Claims

1. A gas generator used in an underwater launching device that fires projectiles underwater, A gas generator comprising multiple modules, each including a plurality of columnar propellant grains parallel to each other and a cylindrical case containing the plurality of propellant grains.

2. The gas generator according to claim 1, wherein the plurality of modules are arranged in multiple stages in the axial direction of the case.

3. The gas generator according to claim 2, wherein the plurality of modules are arranged side by side in each of the plurality of stages.

4. The gas generator according to claim 3, further comprising a hood positioned between the plurality of modules and the projectile, which combines the combustion gases ejected from the plurality of modules and ejects them from the throat.

5. The gas generator according to any one of claims 1 to 4, wherein the case is provided with a plurality of through holes arranged in the circumferential and axial directions.

6. The gas generator according to any one of claims 1 to 4, further comprising a plurality of ignition devices for igniting each of the plurality of propellant grains of the plurality of modules.

7. A bottomed cylindrical containment vessel for storing the projectile, A gas generator according to claim 6 is provided at the bottom of the aforementioned storage container, The gas generator comprises a control device for controlling the plurality of ignition devices, The control device is an underwater launching device that divides the plurality of ignition devices into multiple groups and activates each group sequentially.

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