JPH079218B2 - 2-stage thrust type rocket motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a two-stage thrust type rocket motor having one injection nozzle and two combustion chambers and capable of obtaining two stages of propulsive force. is there.

[Prior Art] In recent years, defense rocket motors and the like have been improved in performance due to higher specific thrust of propellants and weight reduction of motor cases, but there is a limit to the technology for improving these performances.

Therefore, a two-stage thrust type rocket motor has been considered as a method for improving the overall performance of the rocket motor. As a rocket equipped with this type of rocket motor, for example, there is one as shown in FIG.

The two-stage thrust type rocket motor 2 installed in this rocket 1 has one injection nozzle 3 and two first and second combustion chambers 4,
The first and second combustion chambers 4 and 5 are respectively loaded with two types of inner combustion type first and second propellants 6 and 7.

Such first and second combustion chambers 4 and 5 are provided in series, a partition wall 8 is formed between the combustion chambers 4 and 5, and the communication opening 8a formed in the partition wall 8 has a lid 9 The first and second combustion chambers 4 and 5 are defined by being closed at.

The lid 9 is formed of a material such as ceramic that is weak against tensile force but strong against compressive force and has an arc-shaped cross section, and is fixed to the partition wall 8 so as to bulge toward the first combustion chamber 4 side. Has been done.

Thus, when the first propellant 6 on the first combustion chamber 4 side is ignited and burned by an igniter (not shown), the lid 9 is mainly compressed by this combustion pressure, and thus is not destroyed. Combustion is performed only in the combustion chamber 4.

On the other hand, when the second propellant 7 on the side of the second combustion chamber 5 is burned, the lid 9 is crushed by being mainly subjected to a tensile force and is jetted from the jet nozzle 3 to the outside together with the combustion gas. .

In this way, at arbitrary time intervals, the first and second
By burning the propellants 6 and 7, two independent thrust impulses can be generated. Therefore, it is possible to improve the overall performance of the rocket motor, such as extending the range and improving the interception performance.

Note that this kind of product includes AIAA (American Institu
te of Aeronautics and Astronautics) published in 1986 by AIAA-86-1576 `` The Dual-Interrrupted-Thrust
There is something like that described in "Pulse Motor".

[Problems to be Solved by the Invention] However, in such a conventional two-stage thrust type rocket motor 2, due to the combustion pressure in the second combustion chamber 5,
Since the lid 9 is crushed and ejected from the ejection nozzle 3, the fragments may collide with the inner surface of the ejection nozzle 3 and damage the inner surface. Further, since the lid body 9 is made of a brittle material such as ceramic, it is weak against vibration and impact and may be damaged during the combustion of the first propellant 6. Furthermore, if the lid 9 is crushed and opened by the pressure in the second combustion chamber 5, there is a problem that the combustion pressure fluctuates at this time and combustion becomes unstable.

[Means for Solving the Problem] The present invention has been made in view of such a conventional problem, and a partition wall is provided substantially at the center in the longitudinal direction in a cylindrical motor case having an injection nozzle at one end. And the partition wall divides the inside of the motor case into the first combustion chamber on the one end side and the second combustion chamber on the other end side, and the first and second combustion chambers are respectively divided into the first and second combustion chambers. The second propellant is loaded and the first and second propellants are loaded.
A two-stage thrust type rocket motor having a communication port for communicating a combustion chamber formed in the partition wall, the communication port being closed during combustion of the first propellant, and having a port cover opened after completion of combustion. A cylinder portion that opens toward the first combustion chamber is formed in the partition wall, while the port cover includes a lid portion that opens and closes the communication port, and the first portion inside the cylinder portion.
A piston portion slidably inserted from the combustion chamber side to form a pressure chamber, the pressure chamber and the first combustion chamber communicate with each other through an orifice portion, and the port cover has the first combustion chamber. A stopper part that stops the movement of the port cover is formed in a state where the communication port is slid inward and the communication port is opened, and the combustion pressure during combustion in the first combustion chamber is the pressure chamber through the orifice part. And the pressure in the first combustion chamber causes a pressure difference between the first combustion chamber and the pressure chamber, so that the port cover is pushed forward by the pressure in the pressure chamber. The two-stage thrust type rocket motor is characterized by that.

[Operation] According to this means, when the first propellant in the first combustion chamber is ignited and burned, this combustion gas is injected from the injection nozzle to generate a constant propulsive force.

In this state, the pressure in the first combustion chamber acts on the pressure chamber via the orifice portion, and the pressure in this pressure chamber rises.

After that, when the combustion in the first combustion chamber ends and the pressure therein decreases, the pressure remaining in the pressure chamber becomes higher, and when the pressure difference becomes larger than a predetermined value, the port cover moves to the first Slide a predetermined amount to the combustion chamber side. The stopper portion prevents the port cover from coming off the partition wall, the sliding of the port cover is stopped, and the communication port of the partition wall provided between the first and second combustion chambers is opened.

Then, when the second propellant is ignited, the combustion gas becomes the second
From the combustion chamber, the communication port, the first combustion chamber, the injection nozzle, and the second thrust is obtained.

If the port cover is slid to open the communication port of the partition wall in this manner, the lid body is not crushed and ejected from the injection nozzle as in the conventional case, so that the inner surface of the injection nozzle is damaged. Therefore, a constant propulsive force is secured without affecting the flow of combustion gas.

Further, this port cover is not something which is slid with a large combustion pressure in the second combustion chamber, but is due to the pressure difference between the pressure stored in the pressure chamber and the first combustion chamber,
The impact force that acts on the port cover when opening is small. Therefore, it is not necessary for the port cover and the like to have a strong structure capable of withstanding a large impact force, and a reliable operation can be performed, and a large vibration is not transmitted from the port cover to the airframe. . Furthermore, the second propellant is not burned to open the communication port of the partition wall.
When the propellant burns, the communication port is already open, so that unlike the conventional case, the fluctuation of the combustion pressure is small and stable combustion can be obtained.

[Examples] Hereinafter, the present invention will be described based on Examples.

1 to 6 are views showing an embodiment of the present invention.

First, the configuration will be described. In FIG. 1, reference numeral 11 is a cylindrical motor case, and one end portion of the motor case 11 (right end portion in the drawing).
An injection nozzle 12 for injecting combustion gas is provided therein, and a partition wall 13 is provided in the motor case 11 at a substantially central portion in the longitudinal direction. The partition wall 13 divides the first combustion chamber 14 on the injection nozzle 12 side and the second combustion chamber 15 on the other end side.
The first and second combustion chambers 14 and 15 are respectively loaded with the first and second propellants 16 and 17, and the first igniter 29 and the second propellant 17 for igniting the first propellant 16 are also loaded. A second igniter 30 for igniting is provided. This first igniter 29
As shown in FIG. 1, a ring-shaped charge 29b is provided in the case 29a.
Is provided, and the inside of the case 29a and the first combustion chamber 14 are communicated with each other by a plurality of nozzles 29c.

Further, the partition wall 13 is formed with a cylinder portion 18 that bulges toward the second combustion chamber 15 side and opens toward the first combustion chamber 14 side in the central portion, and around the cylinder portion 18, the first and second cylinders 18 are formed. Combustion chamber 14,1
As shown in FIG. 4, a total of three communication ports 19 for communicating the five are formed.

The partition wall 13 is provided with a port cover 20 that opens and closes the communication port 19.

The port cover 20 includes a lid portion 21 that opens and closes the communication port 19.
And a piston portion 22 inserted into the cylinder portion 18. The piston portion 22 has a hollow shape and is inserted into the cylinder portion 18 to
A pressure chamber 23 is formed by 18 and. Around the tip portion (left end portion in the drawing) of the piston portion 22, a sliding contact is made with the inner wall of the cylinder portion 18 mainly through a seal member 24 as shown in FIGS. 2 and 3. A moving part 25 is formed, and an orifice part 26 that connects the pressure chamber 23 and the first combustion chamber 14 is formed. The piston portion 22 allows the port cover 20 to slide in the motor axial direction.

A stopper portion 27 is formed on the partition wall 13 to stop the sliding of the sliding portion 25 of the piston portion 22 when the port cover 20 is slid as shown in FIG. .

The port cover 20 is fixed to the partition wall 13 by a plurality of screws 28 at the peripheral edge of the disk-shaped lid portion 21.

The screw 28 is set so as to be broken by a predetermined pressure described later.

Next, the operation of the two-stage thrust type rocket motor having such a configuration will be described.

First, when the charge 29b is ignited by a device (not shown), a high temperature gas is ejected through the nozzle 29c and the first propellant 16 is ignited. When the first propellant 16 is combusted, the combustion pressure rises in the initial stage of combustion as shown by the curve A in FIG. 6, maintains a substantially constant pressure in the middle period, and decreases in the latter period. In this case, the rise of the pressure in the first combustion chamber 14 acts on the pressure chamber 23 via the orifice portion 26, and the inside of the pressure chamber 23 gradually rises as shown by the curve B in FIG. Then, when the pressure in the first combustion chamber 14 becomes the lowest, the pressure in the pressure chamber 23 becomes the highest, and the pressure difference between the pressure in the pressure chamber 23 and the pressure in the first combustion chamber 14 becomes the port. The screw 28 is acted on via the cover 20 and the screw 28 is cut (at the time point indicated by the broken line C in FIG. 6). In other words, the screws are
28 intensities are set.

With this, the port cover 20 has the piston portion 22 with the cylinder portion.
By sliding inside 18, it moves to the inside of the first combustion chamber 14. Then, the sliding portion 25 of the port cover 20 comes into contact with the stopper portion 27 of the partition wall 13 and the sliding of the port cover 20 stops (at the time point indicated by the broken line D in FIG. 6). With this, the communication port 19 is opened (see FIG. 3).

When the second propellant 17 in the second combustion chamber 15 is ignited by the second igniter 30 after the elapse of a predetermined time, a combustion pressure as shown by a curve E in FIG. 6 is exhibited. This combustion gas is injected from the injection nozzle 12 from the first combustion chamber 14 through the communication port 19 and the second combustion chamber 15.

In this way, the thrust impulses can be generated twice by independently burning the combustion chambers 14 and 15. Therefore, it is possible to improve the overall performance of the rocket motor, such as extending the range and improving the interception performance.

If the port cover 20 is slid to open the communication port 19 of the partition wall 13 in this manner, the lid body is not crushed and ejected from the ejection nozzle 12 as in the conventional case,
The inner surface of the injection nozzle 12 is not damaged, the flow of combustion gas is not affected, and a constant propulsive force is secured.

Further, this port cover 20 is not something which is slid by the large combustion pressure in the second combustion chamber 15, but the pressure chamber 23
This is due to the pressure difference stored in the first combustion chamber 14 and the pressure stored in the first combustion chamber 14, and the impact force that acts on the port cover 20 and the like during opening is small. Therefore, it is not necessary for the port cover 20 and the like to have a strong structure capable of withstanding a large impact force, and it is possible to ensure a reliable operation. There is no.
Further, when the second propellant 17 is burned, the communication port 19 of the partition wall 13 is not opened by burning the second propellant 17, and when the second propellant 17 is burned,
Since the communication port 19 is already open, unlike the conventional case, the fluctuation of the combustion pressure is small, and stable combustion can be obtained.

[Effects of the Invention] As described above, according to the present invention, the port cover is slid to open the communication port. Therefore, it is possible to damage the injection nozzle with a fragment of the lid as in the conventional case. Moreover, it is possible to prevent the pressure fluctuation in the combustion chamber due to the fluctuation of the throat area when passing through the injection nozzle. Further, since the port cover is slid by the pressure difference between the pressure chamber and the first combustion chamber to open the communication port, the second propellant is opened with a large combustion pressure during combustion as in the conventional case. Since it is not a thing, the fluctuation of the combustion pressure is small and stable combustion can be obtained, the impact on the port cover etc. is small and the structure can be simple, and the certainty of the operation is secured. Exerts a beneficial effect.

[Brief description of drawings]

1 to 6 are views showing an embodiment of a two-stage thrust type rocket motor according to the present invention. FIG. 1 is a sectional view of the rocket motor, and FIGS. 2 and 3 show essential parts. Sectional views, FIGS. 4 and 5 are sectional views taken along lines IV-IV and VV of FIG. 1, respectively, FIG. 6 is a graph showing the relationship between pressure and time, and FIG. 7 is conventional. 3 is a partially cutaway side view showing a rocket equipped with the rocket motor of FIG. 11 …… Motor case 12 …… Injection nozzle 13 …… Partition 14 …… First combustion chamber 15 …… Second combustion chamber 16 …… First propellant 17 …… Second propellant 18 …… Cylinder part 19 …… Communication port 20 …… Port cover 21 …… Lid part 22 …… Piston part 23 …… Pressure chamber 26 …… Orifice part 27 …… Stopper part 29 …… First igniter 30 …… Second igniter

Claims (1)

[Claims] 1. A cylindrical motor case having an injection nozzle at one end thereof is provided with a partition wall at a substantially central portion in the longitudinal direction, and the partition wall separates the interior of the motor case from the first combustion chamber on the one end side.
It is divided into the second combustion chamber on the other end side, and the first and second propellants are loaded into the first and second combustion chambers, respectively, and
A two-stage thrust type rocket motor provided with a communication port for communicating the second combustion chamber in the partition wall, the communication port being closed during the combustion of the first propellant and having a port cover opened after the combustion is completed. In the partition wall, a cylinder portion that opens toward the first combustion chamber side is formed, while the port cover includes a lid portion that opens and closes the communication port, and a cylinder portion inside the cylinder portion from the first combustion chamber side. A piston portion that is slidably inserted to form a pressure chamber, communicates the pressure chamber and the first combustion chamber with an orifice portion, and the port cover is slid to the inside of the first combustion chamber. In a state where the communication port is opened, a stopper portion that stops the movement of the port cover is formed, and combustion pressure during combustion in the first combustion chamber is stored in the pressure chamber via the orifice portion. The first combustion chamber A two-stage thrust force is set so that the port cover is pushed by the pressure of the pressure chamber when a pressure difference between the first combustion chamber and the pressure chamber occurs due to a pressure drop inside the pressure chamber. Type rocket motor.