U.S. patent application number 13/708338 was filed with the patent office on 2013-05-16 for two-pulse rocket motor.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. The applicant listed for this patent is MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Katsunori Ieki, Chiyako Mihara.
Application Number | 20130118147 13/708338 |
Document ID | / |
Family ID | 40031743 |
Filed Date | 2013-05-16 |
United States Patent
Application |
20130118147 |
Kind Code |
A1 |
Mihara; Chiyako ; et
al. |
May 16, 2013 |
TWO-PULSE ROCKET MOTOR
Abstract
In the two-pulse rocket motor in accordance with the present
invention, the second propellant is set outside of the first
propellant in a motor case, and the inner surface of the first
propellant is exposed throughout the almost entire length in the
axial direction of the motor case. Therefore, the initial burning
area can be secured without deteriorating the performance. Also, by
providing a weak part by bonding the barrier membranes or shaping
slits on the barrier membrane, the breaking portion of barrier
membrane and the behavior of barrier membrane after breakage can be
controlled. Further, by setting an igniter charge having higher
ignitability and a higher burning rate than the second propellant
between the inner surface of the second propellant and the inner
barrier membrane, the detachment of barrier membrane and the
ignition of the second propellant can be assisted.
Inventors: |
Mihara; Chiyako;
(Komaki-shi, JP) ; Ieki; Katsunori; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI HEAVY INDUSTRIES, LTD.; |
Tokyo |
|
JP |
|
|
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
40031743 |
Appl. No.: |
13/708338 |
Filed: |
December 7, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12599874 |
Nov 12, 2009 |
8397486 |
|
|
PCT/JP2008/058648 |
May 9, 2008 |
|
|
|
13708338 |
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Current U.S.
Class: |
60/256 |
Current CPC
Class: |
F02K 9/28 20130101; F02K
9/95 20130101; F02K 9/08 20130101; F02K 9/12 20130101 |
Class at
Publication: |
60/256 |
International
Class: |
F02K 9/08 20060101
F02K009/08 |
Foreign Application Data
Date |
Code |
Application Number |
May 14, 2007 |
JP |
2007-127801 |
Claims
1. A two-pulse rocket motor having a motor case, comprising: a
first propellant; a second propellant; a second igniter set on an
end surface of the second propellant; a barrier membrane that
covers an initial burning surface of the second propellant entirely
and the second igniter; and wherein the first propellant is loaded
so as to cover the barrier membrane entirely, and wherein the first
propellant and the second propellant each has an internal burning
type or an internal and end burning type of propellant grain
design, and wherein the barrier membrane has notches on it.
2. The two-pulse rocket motor according to claim 1, wherein the
second igniter is set on an aft end surface of the second
propellant.
3. The two-pulse rocket motor according to claim 1, wherein an
igniter charge having higher ignitability and a higher burning rate
than the second propellant is set on an inner surface of the second
propellant.
4. The two-pulse rocket motor according to claim 3, wherein an
igniter charge is set in plural slots, which are shaped on the
inner surface of the second propellant in the axial direction
around the longitudinal axis.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a Divisional of copending application
Ser. No. 12/599,874, filed Nov. 12, 2009, which is a National Stage
of copending PCT International Application No. PCT/JP2008/058648
filed on May 9, 2008. The entire contents of each of the above
documents in hereby incorporated by reference into the present
application.
TECHNICAL FIELD
[0002] The present invention relates to solid propellant rocket
motors which are capable of providing two separate and distinct
propulsive impulses at expected time.
BACKGROUND ART
[0003] Conventionally, a two-phase motor of a solid propellant as
shown in FIGS. 12 and 13 has been proposed. The two-phase motor
includes a pressure vessel 100 having a rear opening that releases
a propellant material, a first pulse explosive grain (a first
propellant) 101 arranged in the rear part of the pressure vessel
100, a second pulse explosive grain (a second propellant) 102
arranged in the front part of the pressure vessel 100, a barrier
isolator (barrier membrane) 103 for isolating the first pulse
explosive grain 101 and the second pulse explosive grain 102 from
each other, and a firing device means arranged in the front part of
the pressure vessel 100 so that the first pulse explosive grain 101
and the second pulse explosive grain 102 can be fired selectively.
The firing device means includes a first pulse firing device
(ignition device) 108 arranged close to the first pulse explosive
grain 101 and a second pulse firing device arranged close to the
second pulse explosive grain 102. The second pulse firing device
includes a firing device blocking body 105 in which an annular
chamber 104 defining a firing device chamber is arranged and a
second firing device explosive grain 106 for firing the second
pulse explosive grain. The firing device blocking body 105 is
provided with at least one nozzle port 107 for providing a path
leading from the annular chamber 104 to the second pulse explosive
grain 102 (for example, Patent Document 1).
[0004] Also, a two-stage thrust type rocket motor as shown in FIGS.
14 and 15 has been proposed. In this rocket motor, an injection
nozzle 113 is disposed at the rear, a first combustion chamber 110
and a second combustion chamber 111 are disposed in the named order
from the injection nozzle 113 directly or via a joint 112 in a
state of being connected in series. In the first combustion chamber
110, a first propellant 114 having a hollow part penetrating
longitudinally is provided, and in the second combustion chamber
111, a second propellant 115 having a hollow part penetrating
longitudinally is provided. In the wall surface at a position at
which the first propellant 114 is selectively fired, one or more
through holes are provided, and in a front-side end part of a first
igniting case (ignition device) 119, a first blocking body 121 to
which a mechanism for firing a first igniting powder 117 is
attached is provided. Also, the first igniting case 119 charged
with the first igniting powder therein is arranged on the
longitudinal axis line in the first combustion chamber. In the wall
surface at a position at which the hollow part wall surface of the
second propellant 115 is fired directly, one or more through holes
are provided, and in the front-side end part of a second igniting
case 120, a second blocking body 122 to which a mechanism for
firing the second igniting powder 118 is attached is provided. The
second igniting case (ignition device) 120 charged with the second
igniting powder 118 therein is disposed in the hollow part of the
second propellant 115, and the outer peripheral end part thereof is
fixed by the entire of circumference of a rocket motor shell part.
A barrier membrane 116 to which the inner peripheral end part of
the second igniting case 120 is fixed is provided between the first
igniting case 119 and the second igniting case 120 so as to isolate
the first propellant 114 and the second propellant 115 from each
other (for example, Patent Document 2). [0005] [Patent Document 1]
Japanese Patent No. 3231778 [0006] [Patent Document 2] Japanese
Unexamined Patent Application Publication No. 2005-171970
DISCLOSURE OF INVENTION
Problem to be Solved by the Invention
[0007] Generally, in the operation of a missile equipped with a
two-pulse rocket motor (a solid propellant rocket motor which is
capable of providing two separate and distinct propulsive impulses
at expected time), the missile is accelerated by the first pulse
(the propulsive impulse generated by first propellant combustion)
and flies toward its target, and when it approaches the target, it
is accelerated again by the second pulse (the propulsive impulse
generated by second propellant combustion) to enhance
maneuverability at the terminal guidance.
[0008] Therefore, in the case of aiming at a remote target, it is
necessary that first propellant mass consumed in the first pulse be
increased to set burn time longer and/or thrust higher.
[0009] However, as for the rocket motor shown in FIGS. 12 and 14,
the first propellant cannot have enough length because the first
propellant and the second propellant are set in the axial direction
of the rocket motor, and the rocket motor length is limited for
equipment or storage.
[0010] If the propellant cannot have enough length, the initial
burning area may reduce and the necessary initial thrust cannot be
achieved in the case that propellant grain design is an internal
burning type as shown in FIGS. 12 and 14.
[0011] For a means of improving the initial thrust, it is effective
to set the plural slits on the inner surface of the propellant to
increase the initial burning area. In that case, however, since
propellant mass in the slit portion is removed, the total impulse
will reduce, which may deteriorate the performance.
[0012] Also, if the first propellant is lengthened, the second
propellant must be shortened because the rocket motor length is
restricted. In that case, since the second propellant cannot have
enough burning area and its combustion gas flow is generated
insufficiently, the necessary thrust cannot be achieved at second
propellant combustion with the nozzle which has the same throat
diameter (the minimum diameter of exhaust hole) at first propellant
combustion.
[0013] Therefore, it is necessary an additional device that can
change the nozzle throat diameter appropriately at each time of
first and second propellant combustion, which increases structural
weight.
[0014] Also, since propellant grain design is such that the two
propellants are set in the axial direction as shown in FIGS. 12 and
14, the thermal barrier membrane is exposed partly to
high-temperature combustion gas from the beginning of first
propellant combustion. Therefore, it is necessary to make the
thermal barrier membrane thicker to protect the second propellant
inside it from heat until the due time of second propellant
combustion, which reduces propellant mass.
[0015] Further, the same can be said of ignition devices, so it is
necessary to protect them from heat until the finish of second
propellant combustion (they coming off, the nozzle may be closed),
which increases structural weight.
[0016] Also, as for the thermal barrier membrane and its holding
structure shown in FIGS. 12 and 14, it is not clear either behavior
(breaking properties) or condition of the remains of the thermal
barrier membrane when the second igniter works. If the barrier
membrane is broken in an unexpected portion, the second propellant
cannot have enough burning area because the barrier membrane does
not detach from the burning surface and cover it.
[0017] Further, if the barrier membrane is broken in the forward
portion, most of it will turn over and detach from the second
propellant toward the nozzle. In that case, combustion or
combustion gas flows of the second propellant can be hindered, and
at worst, the nozzle may be closed by the broken barrier membrane.
In particular, the above-mentioned troubles occur remarkably for
long or small-diameter two-pulse rocket motors.
[0018] It is an object of this invention to provide a two-pulse
rocket motor that can achieve the expected propulsive impulse and
initial thrust of the first propellant and can reduce structural
weight of heat protection for the thermal barrier membrane and the
second igniter by the idea for propellant grain design and the
placement of the second igniter.
[0019] Also, another object of the present invention is to provide
a two-pulse rocket motor in which combustion or combustion gas
flows of the second propellant are not hindered by providing the
barrier membrane and its holding structure considering good
behavior and condition of the remains of the thermal barrier
membrane and further providing a device considering the exposure of
the burning surface of the second propellant and its ignitability
when the second igniter works.
Means for Solving Problem
[0020] The present invention solves the above-mentioned problems by
the following means.
[0021] A two-pulse rocket motor of a first means has a motor case
containing a second propellant, a second igniter set on the end
surface of the second propellant, a barrier membrane that covers
the initial burning surface of the second propellant entirely and
the second igniter, and a first propellant loaded so as to cover
the barrier membrane entirely, and is characterized by the first
propellant and the second propellant each have an internal burning
type or an internal and end burning type of propellant grain
design.
[0022] A two-pulse rocket motor of a second means is, in the
two-pulse rocket motor of the first means, characterized by the
barrier membrane composed of an inner barrier membrane covering the
inner surface of the second propellant and an aft barrier membrane
covering the aft end surface of the second propellant, and the
meeting edges of the aft barrier membrane and the inner barrier
membrane are bonded throughout the entire periphery.
[0023] A two-pulse rocket motor of a third means is, in the
two-pulse rocket motor of the first means, characterized by the
barrier membrane having slits on it.
[0024] A two-pulse rocket motor of a fourth means is, in the
two-pulse rocket motor of any one of the first to third means,
characterized by the second igniter set on the aft end surface of
the second propellant.
[0025] A two-pulse rocket motor of a fifth means is, in the
two-pulse rocket motor of any one of the first to fourth means,
characterized by an igniter charge having higher ignitability and a
higher burning rate than the second propellant set on the inner
surface of the second propellant.
[0026] A two-pulse rocket motor of a sixth means is, in the
two-pulse rocket motor of the fifth means, characterized by the
igniter charge set in plural slits, which are shaped on the inner
surface of the second propellant in the axial direction around the
longitudinal axis.
Effect of the Invention
[0027] The inventions described in the claims employ the above
means and achieve the effects described below.
[0028] According to the two-pulse rocket motor of the first means,
the second propellant is set outside of the first propellant, and
the inner surface of the first propellant is exposed throughout the
almost entire length in the axial direction of the motor case, so
that the initial burning area of the first pulse can be increased.
Therefore, a large slit need not be provided in the inner surface
of the first propellant, and a decrease in total thrust can be
avoided.
[0029] Also, the first propellant is set so as to cover the entire
of barrier membrane, and the barrier membrane is protected from
heat in the first half of first propellant combustion. Therefore,
the plate thickness of barrier membrane can be decreased.
[0030] Also, since the second propellant is set outside of the
first propellant, the burning area of the second propellant does
not become extremely smaller than the burning area of the first
propellant, and a varying mechanism for the throat diameter of
nozzle need not be provided, so that an increase in weight can be
restrained.
[0031] Also, the second propellant is protected from heat until the
operation of the second propellant, and after the operation, there
remains no component in the motor case. Therefore, the weight of
heat-resisting material can be reduced.
[0032] According to the two-pulse rocket motor of the second or
third means, the barrier membrane is divided into two pieces and a
joint part is provided to weaken a portion to be broken or a slit
is formed in the barrier membrane to break the barrier membrane.
Therefore, the barrier membrane is surely broken at an expected
position (weak part) by the pressure of gas generated by the
operation of the second igniter or second propellant
combustion.
[0033] Thereafter, the inner barrier membrane that occupies most of
the barrier membrane deforms toward the center when being separated
from the second propellant, and the holding part of barrier
membrane after deformation lies in the front part of motor case
where the flow due to combustion gas of the second propellant is
relatively gentle, so that the survival properties are
excellent.
[0034] Also, since the aft barrier membrane itself after breakage
is small, when being separated, the aft barrier membrane deforms
naturally in the nozzle-side direction along the flow of combustion
gas of the second propellant, so that the survival properties are
excellent.
[0035] Thus, by breaking the barrier membrane at the expected
position, the deformation shape of barrier membrane after
detachment is made in a state in which condition of the remains is
excellent. Thereby, combustion gas of the second propellant is
exhausted through the exhaust hole of nozzle in such a manner that
the flow is not hindered by the barrier membrane.
[0036] According to the two-pulse rocket motor of the fourth means,
since the second igniter is set on the aft end surface of the
second propellant, the weak part (joint part or slit) of barrier
membrane or a portion to be broken of the barrier membrane can be
broken more surely.
[0037] According to the two-pulse rocket motor of the fifth means,
since the igniter charge having higher ignitability and a higher
burning rate than the second propellant is provided between the
inner surface of the second propellant and the barrier membrane,
the igniter charge is ignited earlier than the second propellant by
the operation of the second igniter. Thereby, the separation of the
inner barrier membrane or the inside portion of the barrier
membrane (exposure of burning surface of the second propellant) and
the ignition of the second propellant are assisted, so that the
second propellant can be burned surely.
[0038] Also, the invention of this means also has an effect that
the pressure at the second pulse is raised quickly by combustion
gas of igniter charge.
[0039] According to the two-pulse rocket motor of the sixth means,
since the igniter charge is set so as to match the shape of the
inner surface of the second propellant, the degree of freedom can
be given to the propellant shape of the second propellant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] FIG. 1 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a first embodiment of the present
invention;
[0041] FIG. 2 is a sectional view taken along the line A-A of FIG.
1;
[0042] FIG. 3 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a second embodiment of the present
invention;
[0043] FIG. 4 is a sectional view taken along the line B-B of FIG.
3;
[0044] FIG. 5 is a longitudinal sectional view showing a state in
which a barrier membrane is deformed at the burn time of second
propellant combustion in a two-pulse rocket motor in accordance
with a second embodiment of the present invention;
[0045] FIG. 6(a) is a sectional view taken along the line C-C of
FIG. 5, and FIG. 6(b) is a sectional view taken along the line D-D
of FIG. 5;
[0046] FIG. 7 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a third embodiment of the present
invention;
[0047] FIG. 8 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a fourth embodiment of the present
invention;
[0048] FIG. 9 is a sectional view taken along the line E-E of FIG.
8;
[0049] FIG. 10 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a fifth embodiment of the present
invention;
[0050] FIG. 11 is a sectional view taken along the line F-F of FIG.
10;
[0051] FIG. 12 is a configuration view of a conventional two-stage
thrust type rocket motor;
[0052] FIG. 13 is a detailed view of an ignition device means of
the two-stage thrust type rocket motor shown in FIG. 12;
[0053] FIG. 14 is a configuration view of another conventional
two-stage thrust type rocket motor; and
[0054] FIG. 15 is a detailed view of a first igniting case and a
second igniting case of the two-stage thrust type rocket motor
shown in FIG. 14.
EXPLANATIONS OF LETTERS OR NUMERALS
[0055] 1 motor case [0056] 2 nozzle [0057] 3 end plate [0058] 4
first propellant [0059] 5 second propellant [0060] 6 first igniter
[0061] 8 second igniter [0062] 10 barrier membrane [0063] 10a aft
barrier membrane [0064] 10b inner barrier membrane [0065] 11
burning region [0066] 12 exhaust hole [0067] 14 igniter charge
BEST MODE(S) FOR CARRYING OUT THE INVENTION
[0068] Tow-pulse rocket motors in accordance with embodiments of
the present invention are now described with reference to the
accompanying drawings.
[0069] FIG. 1 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a first embodiment of the present
invention, and FIG. 2 is a sectional view taken along the line A-A
of FIG. 1.
[0070] FIG. 3 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a second embodiment of the present
invention, and FIG. 4 is a sectional view taken along the line B-B
of FIG. 3.
[0071] FIG. 5 is a longitudinal sectional view showing a state in
which a barrier membrane is deformed at the burn time of second
propellant combustion in the two-pulse rocket motor in accordance
with the second embodiment of the present invention. FIG. 6(a) is a
sectional view taken along the line C-C of FIG. 5, and FIG. 6(b) is
a sectional view taken along the line D-D of FIG. 5.
[0072] FIG. 7 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a third embodiment of the present
invention.
[0073] FIG. 8 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a fourth embodiment of the present
invention, and FIG. 9 is a sectional view taken along the line E-E
of FIG. 8.
[0074] FIG. 10 is a longitudinal sectional view of a two-pulse
rocket motor in accordance with a fifth embodiment of the present
invention, and FIG. 11 is a sectional view taken along the line F-F
of FIG. 10.
First Embodiment of the Present Invention
[0075] First, a two-pulse rocket motor in accordance with a first
embodiment of the present invention is explained with reference to
FIGS. 1 and 2.
[0076] The two-pulse rocket motor in accordance with the first
embodiment burns a first propellant 4 and subsequently burns a
second propellant 5 after arbitrary time has elapsed to produce
two-stage thrust.
[0077] Therefore, during the time before combustion is started, the
second propellant 5 must withstand high-temperature combustion gas
and a high pressure produced by combustion of the first propellant
4.
[0078] Also, it is desirable that the first propellant 4 and the
second propellant 5 can accommodate various thrust patterns by
using a common nozzle 2 by the contrivance of the arrangement and
propellant shape thereof
[0079] As shown in FIGS. 1 and 2, the nozzle 2 having an exhaust
hole 12 for exhausting combustion gas in the center therein is
attached to the rear of a cylindrical motor case 1.
[0080] To the front of the motor case 1, an end plate 3 is
attached, and to the front of the end plate 3, a first igniter 6
for burning the first propellant 4 is attached.
[0081] On the inside of the motor case 1, the first propellant 4
and the second propellant 5 each having a hollow and cylindrical
shape (a propellant shape of an internal burning type or an
internal and end burning type) are charged, and the second
propellant 5 is set outside and the forward part of the first
propellant 4.
[0082] The shape of each of the first propellant 4 and the second
propellant 5 can be a hollow cylindrical shape, a hollow tubular
shape having polygonal inner surface and/or outer surface, a hollow
conical shape, or the like shape.
[0083] The first propellant 4 and the second propellant 5 are
isolated from each other by a barrier membrane 10.
[0084] As being known publicly, as the barrier membrane 10, a
highly heat-resistant rubber such as silicone rubber or EPDM
rubber, containing EPDM rubber, silicone rubber, and inorganic
fiber such as Kevlar fiber as a composition thereof can be
used.
[0085] At the front end of the second propellant 5, a second
igniter 8 for burning the second propellant 5 is provided.
[0086] The second igniter 8 is not limited to one having the
above-described construction. For example, the second igniter 8 may
be configured by a tubular chamber 104, a nozzle port 107, and the
like shown in FIG. 13 (cited document 1).
[0087] The shapes of the first propellant 4, the barrier membrane
10, and the second propellant 5 are not limited to those shown in
FIGS. 1 and 2. The propellant shape, the propellant length, and the
like can be set appropriately according to various thrust
patterns.
[0088] The two-pulse rocket motor in accordance with the first
embodiment of the present invention is configured as described
above. The first igniter 6 is operated by a signal sent from the
outside, by which combustion of the first propellant 4 is started.
At this point of time, the barrier membrane 10 is not exposed to
high-temperature combustion gas.
[0089] When the first propellant 4 burns to the position of the
barrier membrane 10, the barrier membrane 10 is exposed to
high-temperature combustion gas.
[0090] After combustion of the first propellant 4 has finished and
arbitrary time has elapsed, the second igniter 8 is operated by a
signal sent from the outside, by which combustion of the second
propellant 5 is started.
[0091] According to the two-pulse rocket motor in accordance with
the first embodiment of the present invention, the inner surface of
the first propellant 4 is exposed to a burning region 11 throughout
the almost entire length in the axial direction of the motor case
1. Therefore, the initial burning area can be secured, so that a
large slit need not be provided in the inner surface of the first
propellant 4.
[0092] Also, since the second propellant 5 is set outside of the
first propellant 4, the burning area of the second propellant 5
does not become extremely smaller than the burning area of the
first propellant 4, so that the nozzle 2 for the first propellant 4
can be used commonly.
[0093] Also, since the second propellant 5 is set outside of the
first propellant 4 and the barrier membrane 10 is provided
therebetween, the time over which the barrier membrane 10 is
exposed to high-temperature combustion gas can be shortened as much
as possible, so that the barrier membrane 10 can be protected from
heat.
[0094] Further, the second igniter 8 is protected from heat by the
barrier membrane 10 like the second propellant 5, and is burned
down by the operation, so that the protection from heat is not
needed.
[0095] The initial burning surface of the second propellant 5 in
the present invention means a surface burned from the initial stage
when the second propellant 5 begins to burn, that is, a surface
exposed to the burning region 11 first when the second propellant 5
is burned. In the example shown in FIG. 1, the cylindrical inner
surface on the inside of the second propellant 5 and the
ring-shaped rear surface at the rear thereof are the initial
burning surfaces.
Second Embodiment of the Present Invention
[0096] Next, a two-pulse rocket motor in accordance with a second
embodiment of the present invention is explained with reference to
FIGS. 3 to 6.
[0097] In the two-pulse rocket motor in accordance with the second
embodiment of the present invention, the barrier membrane 10 is
divided into two pieces, and a weak part (joint part) is provided
as compared with the first embodiment of the present invention.
[0098] As shown in FIGS. 3 and 4, the barrier membrane 10 covering
the second propellant 5 is formed by a circular truncated cone
shaped aft barrier membrane 10a provided on the rear surface of the
second propellant 5 and a cylindrical inner barrier membrane 10b
provided on the inner surface of the second propellant 5.
[0099] The end part in which the aft barrier membrane 10a and the
inner barrier membrane 10b meet provides the weak part formed by
joining the aft barrier membrane 10a and the inner barrier membrane
10b to each other throughout the entire periphery by using a
fire-resistant adhesive. The joint part is not broken during
combustion of the first propellant 4, and is broken surely by the
pressure of gas generated by the operation of the second igniter 8
or combustion of the second propellant 5.
[0100] Thereafter, as shown in FIGS. 5 and 6, the inner barrier
membrane 10b that occupies most of the barrier membrane 10 deforms
toward the center, and is held in the front part of motor case
where the flow due to combustion gas of the second propellant 5 is
relatively gentle. Also, the broken part of the aft barrier
membrane 10a deforms so as to be turned up to the rear along the
flow of combustion gas.
[0101] According to the two-pulse rocket motor in accordance with
the second embodiment of the present invention, in addition to the
operation and effect of the first embodiment of the present
invention, the breaking properties and the survival properties of
the barrier membrane 10 (the aft barrier membrane 10a, the inner
barrier membrane 10b) are clear and reliable.
[0102] The configuration in which the barrier membrane 10 is
manufactured integrally and a slit is formed in a portion to be
broken and the like configuration can achieve the same effect as
that of the configuration in which the barrier membrane 10 is
divided into two pieces.
Third Embodiment of the Present Invention
[0103] Next, a two-pulse rocket motor in accordance with a third
embodiment of the present invention is explained with reference to
FIG. 7.
[0104] In the two-pulse rocket motor in accordance with the third
embodiment of the present invention, the second igniter 8 is
provided at a position close to the joint part of the barrier
membrane 10 (the aft barrier membrane 10a, the inner barrier
membrane 10b) on the rear end surface of the second propellant 5 as
compared with the first and second embodiments of the present
invention.
[0105] According to the two-pulse rocket motor in accordance with
the third embodiment of the present invention, the operation and
effect of the second embodiment of the present invention are
improved, and the reliability of breaking of the barrier membrane
10 (the aft barrier membrane 10a, the inner barrier membrane 10b)
is increased.
Fourth Embodiment of the Present Invention
[0106] Next, a two-pulse rocket motor in accordance with a fourth
embodiment of the present invention is explained with reference to
FIGS. 8 and 9.
[0107] In the two-pulse rocket motor in accordance with the fourth
embodiment of the present invention, an igniter charge 14 for the
second propellant 5 is charged between the inner surface of the
second propellant 5 and the inner barrier membrane 10b as compared
with the first to third embodiments of the present invention.
[0108] As shown in FIGS. 8 and 9, between the inner surface of the
second propellant 5 and the inner barrier membrane 10b, the
cylindrical igniter charge 14 is charged.
[0109] The igniter charge 14 used has higher ignitability and a
higher burning rate than the second propellant 5.
[0110] The two-pulse rocket motor in accordance with the fourth
embodiment of the present invention is configured as described
above. In burning the second propellant 5, the second igniter 8 is
operated by a signal sent from the outside, and the gas generated
by combustion of the igniter charge 14 assists the separation of
the inner barrier membrane 10b and the ignition of the second
propellant 5.
[0111] According to the two-pulse rocket motor in accordance with
the fourth embodiment of the present invention, in addition to the
operation and effect of the third embodiment of the present
invention, the igniter charge 14 increases the reliability of the
exposure and ignition of burning surface of the second propellant
5.
Fifth Embodiment of the Present Invention
[0112] Next, a two-pulse rocket motor in accordance with a fifth
embodiment of the present invention is explained with reference to
FIGS. 10 and 11.
[0113] In the two-pulse rocket motor in accordance with the fifth
embodiment of the present invention, the igniter charge 14 for the
second propellant 5 is charged by being divided into several pieces
in the circumferential direction as compared with the fourth
embodiment of the present invention.
[0114] As shown in FIGS. 10 and 11, plural slits (grooves) are
shaped on the inner surface of the second propellant 5 in the axial
direction around the longitudinal axis, in which the igniter charge
14 is set.
[0115] According to the two-pulse rocket motor in accordance with
the fifth embodiment of the present invention, which is configured
as described above, in addition to the operation and effect of the
fourth embodiment of the present invention, the degree of freedom
can be given to the propellant shape of the second propellant 5 by
arranging the igniter charge 14 so as to match the shape of the
inner surface of the second propellant 5.
Other Embodiments
[0116] The above is an explanation of the embodiments of the
present invention. However, the present invention is not limited to
the above-described embodiments. It is a matter of course that
various changes can be made within the scope of the present
invention.
[0117] For example, in order to surely break a portion to be broken
of the barrier membrane 10, two-pulse rocket motors consisting of
combinations described below, including the combinations described
in the above embodiments, can be embraced in the present invention.
[0118] (1) A two-pulse rocket motor in which, as shown in FIGS. 3
to 6, the second igniter 8 is set the forward part of the second
propellant 5, the barrier membrane 10 is divided into the aft
barrier membrane 10a and the inner barrier membrane 10b, and the
meeting edges of the aft barrier membrane 10a and the inner barrier
membrane 10b are bonded throughout the entire periphery (by an
adhesive etc.). [0119] (2) A two-pulse rocket motor in which the
second igniter 8 is set the forward part of the second propellant
5, and the barrier membrane 10 has slits on the expected breaking
portion of it. [0120] (3) A two-pulse rocket motor in which the
second igniter 8 is set on the aft end surface of the second
propellant 5. [0121] (4) A two-pulse rocket motor in which, as
shown in FIG. 7, the barrier membrane 10 is divided into the aft
barrier membrane 10a and the inner barrier membrane 10b, and the
meeting edges of the aft barrier membrane 10a and the inner barrier
membrane 10b are bonded throughout the entire periphery (by an
adhesive etc.), and the second igniter 8 is set on the aft end
surface of the second propellant 5. [0122] (5) A two-pulse rocket
motor in which the barrier membrane 10 has slits on the expected
breaking portion of it, and the second igniter 8 is set on the aft
end surface of the second propellant 5. [0123] (6) A two-pulse
rocket motor in which the second igniter 8 is set the forward part
of the second propellant 5, and the igniter charge 14 having higher
ignitability and a higher burning rate than the second propellant 5
is set on the inner surface of the second propellant 5. [0124] (7)
A two-pulse rocket motor in which the barrier membrane 10 is
divided into the aft barrier membrane 10a and the inner barrier
membrane 10b, and the meeting edges of the aft barrier membrane 10a
and the inner barrier membrane 10b are bonded throughout the entire
periphery (by an adhesive etc.), the second igniter 8 is set the
forward part of the second propellant 5, and the igniter charge 14
having higher ignitability and a higher burning rate than the
second propellant 5 is set on the inner surface of the second
propellant 5. [0125] (8) A two-pulse rocket motor in which the
second igniter 8 is set on the aft end surface of the second
propellant 5, and the igniter charge 14 having higher ignitability
and a higher burning rate than the second propellant 5 is set on
the inner surface of the second propellant 5. [0126] (9) A
two-pulse rocket motor in which, as shown in FIGS. 8 and 9, the
barrier membrane 10 is divided into the aft barrier membrane 10a
and the inner barrier membrane 10b, and the meeting edges of the
aft barrier membrane 10a and the inner barrier membrane 10b are
bonded throughout the entire periphery (by an adhesive etc.), the
second igniter 8 is set on the aft end surface of the second
propellant 5, and the igniter charge 14 having higher ignitability
and a higher burning rate than the second propellant 5 is set on
the inner surface of the second propellant 5. [0127] (10) A
two-pulse rocket motor in which the barrier membrane 10 has slits
on the expected breaking portion of it, the second igniter 8 is set
on the aft end surface of the second propellant 5, and the igniter
charge 14 having higher ignitability and a higher burning rate than
the second propellant 5 is set on the inner surface of the second
propellant 5. [0128] (11) A two-pulse rocket motor in which the
second igniter 8 is set the forward part of the second propellant
5, and the igniter charge 14 is set in the plural slits shaped on
the inner surface of the second propellant 5 in the axial direction
around the longitudinal axis. [0129] (12) A two-pulse rocket motor
in which the barrier membrane 10 is divided into the aft barrier
membrane 10a and the inner barrier membrane 10b, and the meeting
edges of the aft barrier membrane 10a and the inner barrier
membrane 10b are bonded throughout the entire periphery (by an
adhesive etc.), the second igniter 8 is set the forward part of the
second propellant 5, and the igniter charge 14 is set in the plural
slits shaped on the inner surface of the second propellant 5 in the
axial direction around the longitudinal axis. [0130] (13) A
two-pulse rocket motor in which the second igniter 8 is set on the
aft end surface of the second propellant 5, and the igniter charge
14 is set in the plural slits shaped on the inner surface of the
second propellant 5 in the axial direction around the longitudinal
axis. [0131] (14) A two-pulse rocket motor in which, as shown in
FIGS. 10 and 11, the barrier membrane 10 is divided into the aft
barrier membrane 10a and the inner barrier membrane 10b, and the
meeting edges of the aft barrier membrane 10a and the inner barrier
membrane 10b are bonded throughout the entire periphery (by an
adhesive etc.), the second igniter 8 is set on the aft end surface
of the second propellant 5, and the igniter charge 14 is set in the
plural slits shaped on the inner surface of the second propellant 5
in the axial direction around the longitudinal axis. [0132] (15) A
two-pulse rocket motor in which the barrier membrane 10 has slits
on the expected breaking portion of it, the second igniter 8 is set
on the aft end surface of the second propellant 5, and the igniter
charge 14 is set in the plural slits shaped on the inner surface of
the second propellant 5 in the axial direction around the
longitudinal axis.
* * * * *