JP2014185792A - Propellant powder ignition primer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a propellant powder ignition primer capable of preventing damage of the primer by restricting irregular combustion pressure of propellant powder and also avoiding delay in ignition and misfire of propellant powder.SOLUTION: A primer 20 is installed at the inner rear end of a cartridge case so as to ignite propellant powder filled in the cartridge case to whose extremity end a bullet is fixed. A plurality of rod-like ignition powder 23 are filled in hollow cylindrical fire shells 21 having several through-holes 22 at peripheral walls, along axial directions of the fire shells 21. This invention is characterized in that a total volume of the ignition powder 23 is 25 to 75% of an inner space volume of the shells 21 and the inner space of the shells has an axial continuous space K. In addition, a length of the rod-like ignition powder 23 is equal to or more than 45% of the inner space length of the shells 21 and an aspect ratio of the rod-like ignition powder 23 is equal to or more than 10.

Description

  The present invention relates to a gun for igniting a propellant used for ammunition such as a medium caliber gun such as a machine gun and a large caliber gun such as a tank gun.

  Generally, this type of ammunition 1 includes a bottomed cylindrical cartridge case 10, a bullet 11 fixed to the tip opening of the cartridge case 10, and a propellant 12 filled in the cartridge case 10, as shown in FIG. And a fire tube 20 for propellant ignition disposed at the rear end (bottom) of the cartridge case 10. As shown in FIG. 2, the fire tube 20 includes a hollow cylindrical fire tube body 21 having a plurality of through holes (flash holes) 22 in the peripheral wall, an ignition agent 23 filled in the fire tube body 21, A detonator 24 disposed at the rear end (bottom) of the fire tube 20 for igniting the ignition agent 23. When the igniting agent 23 is ignited by the firing of the detonator 24, the combustion gas of the igniting agent 23 is ejected from the flash hole 22 of the fire tube 21, the propellant 12 is ignited, and the bullet 11 is launched by the combustion gas. Is done. Conventionally, granular igniter is generally used.

  However, this type of fire tube has a problem that an abnormal combustion pressure is generated at the tip of the fire tube and the tip of the fire tube is damaged. Specifically, a combustion wave of an igniting agent that propagates from the rear end of the fire tube toward the front end of the fire tube is generated by ignition of the detonator. At this time, if there is no space continuous in the axial direction (combustion wave traveling direction) in the fire tube, since the flame is blocked by the unburned ignition agent, the combustion wave compresses the unburned ignition agent ahead of the combustion wave. While proceeding. As a result, the filling density of the igniting agent increases as the combustion wave approaches the tip of the fire tube. Furthermore, the igniter has a pressure dependency represented by r = a · P ^ n, where r is the combustion rate of the igniter, P is the pressure around the igniter, and a and n are coefficients. The explosive burning rate increases exponentially as the pressure around the igniter increases. Therefore, an increase in the filling density of the igniting agent and an increase in the igniting agent combustion speed are combined, and the combustion pressure in the vicinity of the combustion wave increases as the combustion wave advances toward the tip of the fire tube. Eventually, an abnormal combustion pressure of several hundred MPa or more is generated at the tip of the fire tube, and the tip of the fire tube may be damaged.

  On the other hand, Patent Documents 1 to 5 below have been proposed as techniques for suppressing abnormal pressure (differential pressure) of a propellant and improving the ignition performance of the propellant during low temperature use. In Patent Literature 1, the diameter of the flash hole on the front end side of the fire tube is made larger than the hole diameter on the rear end side, or the diameter of the flash hole on the front end side of the fire pipe is inclined in the length direction of the fire tube. In Patent Document 2, an ignition passage is provided between the inner cylinder and the fire tube as an internal / external double structure in which the inner cylinder is provided inside the fire tube. In Patent Document 3, the length of the fire tube is set to 0.3 to 0.7 times the case length, the total hole area of the flash hole is set to 0.01 to 0.04 times the area of the outer periphery of the case, and the outer periphery of the fire tube The number of holes per square centimeter of the surface area is 0.3 to 1.0. In Patent Document 4, the length of the igniting agent is made into a rod-like or tubular shape larger than the length of the fire tube, and the igniting agent is fixed to the combustible holding part, and the fire tube is passed through the fire tube insertion hole of the combustible holding part. It is arranged. In Patent Document 5, the flash hole is provided so as to be unevenly distributed at the tip of the fire tube. Patent Documents 1 to 3 also describe that a rod-shaped ignition powder can be used.

JP 2001-311598 A JP 2001-311599 A JP2001-311600 JP2007-64586 JP2009-97728A

  Patent Documents 1 to 5 attempt uniform combustion of the propellant, but do not pay particular attention to damage to the fire tube due to abnormal combustion pressure in the fire tube. In Patent Documents 1, 3, and 5, the hole diameter and opening position of the flash hole are adjusted. However, it is not possible to cope with the abnormal combustion pressure in the fire tube only by adjusting the flash hole. In Patent Document 2, the fire tube has an internal / external double structure, and an axial continuous space is provided between the inner tube and the fire tube body (outer tube). Since there is no continuous space, it does not lead to the solution of abnormal combustion pressure in the fire tube. Even in Patent Document 4, the igniting agent is only made longer than the fire tube, and it still does not solve the abnormal combustion pressure in the fire tube.

  On the other hand, as a method for avoiding damage to the fire tube, a method of simply reducing the amount of the ignition charge is conceivable. However, if the amount of the igniting agent is reduced, the amount of the igniting agent combustion gas necessary for igniting the propellant is reduced, so that the combustion behavior of the propellant becomes unstable, causing an ignition delay or a failure.

  Therefore, as a result of intensive investigations on a method for avoiding damage to the fire tube due to the occurrence of the abnormal combustion pressure, the present inventors have found a gap between the sparks in the internal space of the fire tube filled with the sparks. It has been found that the above problem can be solved by forming and securing the traveling path of the ignition powder combustion wave, and the present invention has been achieved. That is, an object of the present invention is to provide a gun for igniting a propellant that can suppress an abnormal combustion pressure of the igniter and prevent the fire tube from being damaged, and can also avoid the ignition delay and misfire of the propellant. is there.

  As a means for this, the present invention is a propellant ignition tube disposed at the rear end of the cartridge case for igniting the propellant charged in the inside of the cartridge case with a bullet fixed to the tip. In the hollow tubular fire tube body having a plurality of through holes in the peripheral wall, a plurality of rod-shaped igniters are filled along the axial direction of the fire tube body, and the total volume of the igniter is It is 25 to 75% of the internal space volume of the fire tube body, and the internal space of the fire tube body has a space continuous in the axial direction.

  At this time, the length of the igniting agent is preferably 45% or more of the internal space length of the fire tube body, and the aspect ratio (length / diameter) of the igniting agent is preferably 10 or more.

  According to the present invention, after the igniting agent is formed in a rod shape (long shape), and the filling rate is 75% or less, a space is formed between the igniting agents and an axially continuous space is formed. Arise. As a result, the traveling path of the igniter combustion wave is secured, so that the unburned igniter is not pressed by the combustion wave, the occurrence of abnormal combustion pressure in the fire tube is suppressed, and the fire tube is prevented from being damaged. The On the other hand, since the filling rate of the igniting agent is 25% or more, there is no occurrence of ignition delay or misfire of the propellant.

  If the length of the igniting agent is 45% or more of the internal space length of the fire tube body and the aspect ratio of the igniting agent is 10 or more, a space continuous in the axial direction can be surely formed. Damage can be prevented more reliably.

It is sectional drawing of an ammunition. It is a sectional side view of a fire pipe. It is radial direction sectional drawing of a fire pipe. It is a schematic sectional drawing which shows a rupture disk bomb test apparatus.

  Hereinafter, typical embodiments of the present invention will be described. The fire tube of the present invention is arranged with a propellant in a cartridge case to ignite a propellant that fires a bullet in an ammunition such as a medium caliber gun such as a cannon or a large caliber gun such as a tank gun. It is.

  As shown in FIG. 1, the ammunition 1 includes a bottomed cylindrical cartridge case 10, a bullet (flying body) 11 fitted and fixed to the tip opening of the cartridge case 10, and a plurality of pieces filled in the cartridge case 10. It is comprised by the propellant 12 and the fire tube 20 arrange | positioned in the cartridge case 10. As shown in FIG. Reference numeral 13 denotes a bullet band provided on the outer peripheral surface of the bullet 11. The fire tube 20 is screwed into the central portion of the bottom wall of the case 10 in the radial direction, and extends in the axial direction from the rear end in the case 10 toward the front end side.

  As shown in FIG. 2, the fire tube 20 of the present embodiment includes a hollow cylindrical fire tube body 21 whose front end and rear end are open, an igniting agent 23 filled in a housing space in the fire tube body 21, and A plug 25 for closing the front end opening of the fire tube 21 and a detonator support 26 for closing the rear end of the fire tube 21 are provided. It is also possible to use a fire tube body integrally including the embolus 25 and the fire tube body 21, that is, a ceiling tube-shaped fire tube body whose rear end is open.

  A plurality of through holes are formed in the peripheral wall of the fire tube body 21 as flash holes for releasing the combustion gas of the ignition agent 23 to the outside. The material of the fire tube body 21 is not particularly limited, and any material conventionally used in this type of fire tube can be used. Examples thereof include metal materials such as iron, brass, stainless steel, and aluminum, and burnout materials mainly composed of pulp and nitrocellulose. In view of the strength, workability, and handleability of the fire tube 21, a metal material is preferable, and iron and brass are particularly preferable.

  The embolus 25 is screwed into the tip opening of the fire tube body 21 in order to seal the ignition agent 23. The embolus 25 may be made of the same material as the fire tube 21, and the shape thereof is not particularly limited. Specific examples include a flat plate shape, a truncated cone shape having a convex outer surface, a conical shape, and a hemispherical shape having a convex outer surface. If the outer surface has a convex shape, it is easy to insert when the fire tube 20 is inserted into the cartridge case 10 after the gunpowder 10 is filled with the propellant 12 in advance. FIG. 2 shows a flat-shaped embolus 25.

  The detonator support 26 may be made of the same material as the fire tube 21. The detonator support 26 has a bottomed cylindrical shape that is slightly larger in diameter than the fire tube 21, and is screwed into the rear end portion of the fire tube 21. In addition, a detonator 24 for igniting the igniting agent 23 is disposed in the central portion of the detonator support 26 in the radial direction. The detonator 24 is ignited by an electric signal or a shock.

  The igniting agent 23 is a chemical that can instantly start combustion when the detonator 24 ignites. The material for the igniter 23 is not particularly limited, and any material conventionally used in this type of fire tube can be used. Specific examples include one or more selected from benite, black powder, boron nitrate, smokeless powder, and the like. Among these, in view of the ignitability and handling properties of the propellant 12, benite and black powder are preferable. Benite is a composition containing nitrocellulose, potassium nitrate, sulfur, charcoal, and ethyl central.

  The shape of the igniting agent 23 is at least a rod shape longer than the inner diameter of the fire tube 21. The cross-sectional shape is not particularly limited as long as it is a rod shape, and may be a circle or an ellipse, or a polygon such as a rectangle or a hexagon. Among these, in order to form a gap (a continuous space K described later) between the igniting agents 23, a circular shape or an elliptical shape is preferable. In addition, as shown in FIGS. 2 and 3, a plurality of ignition agents 23 are filled in the internal space of the fire tube body 21 along the axial direction of the fire tube 20.

  At this time, the filling rate of the igniting agent 23 (total volume of the igniting agent 23 / internal space volume of the fire tube 21 × 100) is 25 to 75%, preferably 35 to 75%. As a result, a gap is created between the igniting agents 23, and a space K that is continuous in the axial direction from the rear end to the tip end is formed in the internal space of the fire tube 21 (accommodating space for the igniting agent 23). If the filling rate of the igniting agent 23 is less than 25%, there is a possibility that ignition delay or misfire to the propellant 12 may occur. On the other hand, when the filling rate of the igniting agent 23 exceeds 75%, a gap is hardly generated between the igniting agents 23.

  The length of the igniting agent 23 is 45% or more, preferably 70% or more, more preferably 90% or more of the internal space length of the fire tube 21. If the length of the igniting agent 23 is less than 45% of the internal space length of the fire tube body 21, it is difficult to form an axially continuous space in the fire tube body 21. The upper limit of the length of the ignition agent 23 is 100% with respect to the internal space length of the fire tube 21.

  The diameter of the igniting agent 23 is not particularly limited, and may be set as appropriate according to the pressure resistance of the fire tube 21, the diameter and number of the flash holes 22, the composition of the igniting agent 23, and the like. However, the aspect ratio (length / diameter) of the igniting agent 23 is set to 10 or more, preferably 20 or more, more preferably 40 or more. If the aspect ratio of the igniting agent 23 is less than 10, it becomes nearly granular, and it becomes difficult to form a space that is continuous in the axial direction in the fire tube 21.

  In the ammunition 1 provided with such a fire tube 20, when the ignition powder 23 is ignited by the firing of the detonator 24, the combustion gas of the ignition powder 23 is ejected from the flash hole 22 of the fire tube body 21. As a result, the propellant 12 is ignited, and the bullet 11 is fired by the combustion gas. At this time, in the fire tube 20, gaps are formed between the respective ignition agents 23, and the internal space of the fire tube body 21 has a space K continuous in the axial direction. Therefore, even if the igniting agent 23 is ignited, the combustion progress path is secured, so that the generation of abnormal combustion pressure in the fire tube 20 is suppressed, and the fire tube is prevented from being damaged.

  Specific examples of the present invention will be described below, but the present invention is not limited thereto. The igniter includes benite containing 40% by weight of nitrocellulose, 44.3% by weight of potassium nitrate, 6.1% by weight of sulfur, 9.1% by weight of charcoal, and 0.5% by weight of ethyl central. used. And the ignition agent of circular cross-sectional shape was manufactured using the well-known solvent drawing method which consists of a process of kneading, drawing, cutting, and drying. The dimensions of the propellant were set to a diameter D = 2 to 5 mm and a length L = 2 to 350 mm in accordance with Examples and Comparative Examples described later.

  The dimensions of the fire tube were an internal length of 105 to 400 mm, an internal diameter of 12 to 17 mm, and a side thickness of 5 mm. The diameter of the flash holes was 3 mm, and the flash holes were arranged in a zigzag pattern every 20 mm along the length of the fire tube. The length of the screw part to be fitted with a detonator support described later was 12 mm, and the screw pitch was 1.5 mm. Moreover, the length of the screw part fitted with the embolus was 12 mm, and the pitch of the screw was 1.5 mm. S45C was used for the material of the fire tube.

  An electric ignition type detonator was incorporated in the detonator support, and 0.5 g of black powder was loaded in the detonator. The dimensions of the screw part to be fitted with the fire tube were as described above. S45C was used as the material for the detonator support. The embolus was disc-shaped. The dimensions of the screw part to be fitted with the fire tube were as described above. S45C was used as the embolization material.

  Next, a rupture disc bomb test using the rupture disc bomb 31 will be described with reference to FIG. The rupture disc bomb 31 interrupts the combustion of the propellant 12 when the metallic rupture disc 32 is broken, and is a test apparatus that can acquire the combustion behavior in the pressure region until the rupture disc 32 breaks. is there. The bomb body 33 is formed in a bottomed cylindrical shape, and the fire tube 20 is fixed to the center of the inner surface of the bottom wall 34. A rupturable plate 32 is disposed at the open end of the bomb body 33 so as to close the open end, and the rupturable plate 32 is fixed to the bomb main body 33 by a rupturable plate pressing member 36 formed in a substantially cylindrical shape. ing. A combustion space 37 having a volume of about 9500 ml (diameter 150 mm, depth 550 mm) is provided in the bomb body 33, and the propellant 12 is loaded in the combustion space 37. An electric cable 38 is wired to the detonator of the fire tube 20.

  A pressure transducer 40 is attached to an intermediate portion of the peripheral body 39 of the bomb body 33, and the pressure transducer 40 is communicated with the combustion space 37. Then, the relationship between the combustion time (ms) and the combustion pressure (MPa) when the propellant 12 burned was measured with an oscilloscope (not shown) via the pressure transducer 40. The ignition signal time was set to 0, and 10% arrival time of the maximum pressure value in the rupture disc bomb was determined as the ignition delay time.

  The propellant 12 filled in the rupturable bomb 31 has a typical M30 composition. Specifically, it contains 28% by weight of nitrocellulose, 22.5% by weight of nitroglycerin, 47.7% by weight of nitroguanidine, 1.5% by weight of stabilizer, and 0.3% by weight of anti-inflammatory agent. It was set as the composition. The propellant 12 was manufactured into a 7-hole circular cross-sectional shape by using a known solvent drawing method comprising steps of kneading, drawing, cutting, and drying. The dimensions of each propellant 12 were a diameter D = 14 mm, a length L = 14 mm, and a through hole diameter = 0.5 mm. Then, using the fire tube body and the igniting agent having the dimensions shown in Table 1, the propellant igniting fire tube was evaluated in the following manner. The results are also shown in Table 1.

[Evaluation method of fire tube damage]
A fire test with a single fire tube was conducted and evaluated. The detonator support of the fire tube was fixed with a vise, and the current was required to ignite the detonator to burn the fire tube. As criteria for judgment, fire tubes, detonator supports, and emboli with no deformation / breakage were judged as good (◯), and those with deformation / breakage were judged as poor (×).

[Evaluation method of ignition delay]
The ignition delay was evaluated by a rupture disc bomb test. Those with an ignition delay time of less than 200 ms were judged as good (◯), and those with an ignition delay of 200 ms or more were judged as bad (×). In addition, the thing which a failure | damage occurred in the combustion test with the fire pipe single-piece | unit was set as un-evaluated (-).

  As can be seen from the results in Table 1, in Examples 1 to 4, since there is a continuous space between the igniting agents, the fire tube is not damaged, and the ignition delay time is suppressed to less than 200 ms. confirmed.

  On the other hand, in Comparative Example 1, since there was no space continuous in the axial direction, abnormal pressure was generated at the tip of the fire tube, and the fire tube was damaged. In Comparative Example 2, the size of the igniting agent was made larger than that in Comparative Example 1, but the fire tube was damaged as in Comparative Example 1. In Comparative Example 3, the length of the ignition agent was made longer than that in Comparative Example 1, but the fire tube was broken in the same manner as Comparative Example 1. In Comparative Example 4, it was possible to avoid damage to the fire tube by reducing the amount of ignition agent, but the ignition delay time was 200 ms or more, and the ignition performance was insufficient. In Comparative Example 5, as in Comparative Example 1, the fire tube was damaged.

1 ammunition 10 shell 11 bullet 12 projectile 20 fire tube 21 fire tube body 22 flash hole 23 igniter 24 detonator 25 embolus 26 detonator support 31 rupture disk bomb 32 rupture disk 40 pressure transducer K continuous space

Claims (2)

In order to ignite a propellant filled in a cartridge case with a bullet fixed to the tip, a propellant ignition tube disposed at the rear end of the cartridge case,
Inside the hollow tubular fire tube body having a plurality of through holes in the peripheral wall, a plurality of rod-shaped ignition powders are filled along the axial direction of the fire tube body,
The total volume of the igniting agent is 25 to 75% of the internal space volume of the fire tube,
The propellant-igniting fire tube having an axially continuous space in the internal space of the fire tube body. The length of the ignition powder is 45% or more of the internal space length of the fire tube body,
The propellant-ignited fire tube according to claim 1, wherein the aspect ratio of the igniter is 10 or more.

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