EP2913628A1 - Artillery projectile warhead fuse comprising a braking device acting in flight direction - Google Patents

Abstract

The invention relates to an ogive rocket for a gyro-stabilized artillery projectile, a rocket incorporating a device (6) for translational braking comprising at least two flaps (7a, 7b, 7c) deployable radially on a trajectory so as to increase the aerodynamic drag of the projectile. Each flap comprises at least two closed grooves (22,23) each cooperating with a rod (21a, 21b, 21c) which is fixed relative to a body of the rocket, grooves disposed on either side of a notch ( 26) which is intended to allow positioning of the flap in the folded position around a central portion (14) of the body. This rocket is characterized in that the indentation (26) of each flap (7a, 7b, 7c) comprises end tips (41) which are engaged in indentations (42) of complementary shapes which are carried by a part holding device (43a, 43b, 43c) connected to the rocket (3).

Description

The technical field of the invention is that of artillery projectile warhead rockets that incorporate a translational braking device to increase the aerodynamic drag of the projectile.

We know by the patent EP1045221 such a rocket which comprises at least two radially deployable flaps.

Rockets with ogive braking can increase the accuracy of artillery fire by taking into account dispersions due to variations in the initial velocity of the projectile. In fact, it is then possible to point the weapon so as to fire farther than the target, a firing line measures the actual speed of the projectile at the exit of the barrel of the weapon and a braking command is then transmitted to the projectile so as to reduce its range and thus bring it to the desired point of impact.

The flaps of the rocket described by the patent EP1045221 each comprise two closed grooves substantially parallel to a direction perpendicular to the axis of the rocket, each groove cooperating with a rod which is fixed relative to the rocket. Thus the flaps are translated radially. Each flap comprises a notch which partially surrounds an axial support of the rocket, each flap thus has a U-shape.

This architecture makes it possible to obtain an increased mechanical resistance of the shutters to the aerodynamic forces while ensuring a symmetry of perfect deployment.

However, it was observed that, due to the centrifugal forces experienced during firing, the U-shaped flaps were subject to deformation at the notch (opening of the U). This distortion, combined with the games functional shutters and guide rods, leads to blockages or jamming flaps that hinder the symmetry of the deployment.

It is the object of the invention to provide a shutter architecture allowing a simple way to overcome such a disadvantage.

Thus, the subject of the invention is an ogive rocket for a gyro-stabilized artillery projectile, a rocket incorporating a translational braking device comprising at least two radially deployable flaps on a trajectory so as to increase the aerodynamic drag of the projectile, each flap comprising at least two closed grooves substantially parallel to a direction perpendicular to the axis of the rocket, each groove cooperating with a rod which is fixed relative to a body of the rocket, grooves disposed on either side of a notch which is intended to allow the positioning of the flap in the folded position around a central part of the body of the rocket, rocket characterized in that the notch of each flap comprises end nozzles which are engaged in fingerprints of complementary shapes which are carried by a holding part connected to the rocket.

The holding piece may comprise an internal medial portion which is engaged in the notch of a flap in the folded position, the middle portion which is extended by two wings, each wing having a cavity receiving one of the flaps of the flap.

The holding part may comprise a circular outer profile which will extend the outer profile of the shutter.

The rocket may comprise three regularly angularly distributed flaps, three rods also regularly distributed angularly guiding the various flaps, each rod also ensuring the maintenance of a holding part.

Advantageously, each flap can be housed in a groove of the body of the rocket groove which is delimited by partitions or surfaces of the body which are parallel to each other.

According to another feature, at least one partition has a clearance allowing the passage of a pin carried by a flap disposed on one side of said partition, pin which engages in a notch carried by another flap disposed of the other side of said partition.

• La figure 1 montre schématiquement un projectile équipé d'une fusée selon l'invention.
• La figure 2 représente en coupe longitudinale partielle une fusée de projectile selon l'invention.
• La figure 3 est une vue en coupe du dispositif de freinage de la fusée, représenté en position repliée, coupe suivant le plan AA repéré à la figure 2.
• La figure 4 est une vue analogue à la figure 3 mais le dispositif de freinage est en position dépliée et le corps de fusée n'est pas représenté.
• La figure 5 est une vue montrant un volet de freinage seul ainsi que la pièce de maintien associée.
• La figure 6 est une vue analogue à la figure 4 mais avec le corps de fusée visible.

The invention will be better understood on reading the following description of particular embodiments, a description given with reference to the accompanying drawings and in which:

• The figure 1 schematically shows a projectile equipped with a rocket according to the invention.
• The figure 2 represents in partial longitudinal section a projectile rocket according to the invention.
• The figure 3 is a sectional view of the rocket braking device, shown in the folded position, section along the plane AA marked at the figure 2 .
• The figure 4 is a view similar to the figure 3 but the braking device is in the unfolded position and the rocket body is not shown.
• The figure 5 is a view showing a single braking shutter and the associated holding part.
• The figure 6 is a view similar to the figure 4 but with the visible rocket body.

Referring to the figure 1 , an artillery projectile 1 is provided at its rear portion with a belt 2 intended to take the stripes of a weapon tube (not shown) and to seal the propellant gases when firing the projectile . This projectile carries at its front part a rocket 3 according to the invention, rocket which is intended in a conventional manner and according to the type of projectile considered (explosive projectile or cargo projectile) to provide either the initiation of an explosive charge disposed inside the projectile, or the ignition of a gas-generating charge for ejecting a payload arranged inside the trajectory of the projectile.

For this purpose the rocket comprises an electronic control device 4 which causes the initiation of a pyrotechnic charge 5 (which is depending on the case a detonation relay or a gas generator).

In accordance with the invention, this rocket 3 also incorporates a device for braking in translation 6 enabling the radial deployment on the trajectory of braking flaps 7. The deployment of the flaps 7 is controlled by the electronic control device 4 in response to an order received. on trajectory via a receiver 8 or developed by the electronic control device 4 as a result of a pre-shooting program, or else that is modified in the first moments after firing to take into account the initial speed the projectile.

The trajectory programming will be provided via the receiver 8 which may be radar technology.

The figure 2 shows this rocket in more detail.

It has a general shape and a footprint similar to that of conventional artillery rockets. It comprises a body 13 on which is made a thread 9 intended to allow its attachment to the projectile. The pyrotechnic charge 5 is disposed in a cup secured to the body and communicates through a priming channel 10 with an initiating component 11 (primer or igniter) with electrical release, which is itself connected to the electronic device order 4.

In a conventional manner and which is not described or shown in detail, the initiation component 11 is carried by a movable flap 12 of a safety and arming device (not shown).

The body 13 of the rocket comprises at a front part three annular grooves 17a, 17b and 17c which are delimited by three parallel partitions 15a, 15b and 15c as well as by a rear annular bearing surface 16 of the body 13.

The grooves extend radially to a central portion 14 of the substantially cylindrical body and which is traversed by the channel 10.

The upper partition 15a receives an upper portion of the rocket enclosing the electronic device 4.

The annular grooves 17a, 17b, 17c receive the braking device 6 which comprises three flaps 7. According to this embodiment of the invention, three flaps 7 of identical shapes are integral with the body 13. These flaps are marked 7a, 7b and 7c on figures 3 , 4 and 6 to distinguish them from each other.

Each flap is capable of translating in a plane perpendicular to the axis 20 of the projectile. It is guided in its translation by two cylindrical rods 21 which are fixed (here only one rod 21b is visible). Each rod is disposed between the upper wall 15a and a hole 18 carried by the rear portion of the body 13. The rods 21 are all parallel to the axis 20 of the projectile and the rocket. They are forced into the holes 18.

The figure 3 shows the distribution of the rods 21. Three rods 21a, 21b and 21c are provided and distributed angularly in a regular manner around the axis 20 of the rocket (equidistant from the axis 20 and with an angle of 120 ° between each position).

Each rod 21 is cylindrical and cooperates with four coaxial holes drilled in the three partitions 15a to 15c and only in the body 13 (the latter hole is marked 18 in the figures).

Each flap 7a, 7b and 7c comprises two closed grooves 22 and 23 generally parallel to a direction 24 perpendicular to the axis 20 of the projectile. The grooves 22 and 23 and the direction 24 are marked on the figures 2 and 3 by the designations 22a, 22b, 22c, 23a, 23b, 23c and 24a, 24b, 24c to distinguish the flaps and their structural and geometric elements relative to each other.

The upper flap 7a has two grooves 22a, 23a parallel to a direction 24a.

The median flap 7b has two grooves 22b, 23b parallel to a direction 24b.

The lower flap 7c has two grooves 22c, 23c parallel to a direction 24c.

The three directions 24a, 24b and 24c, intersect the axis 20 of the rocket, they are perpendicular to this axis and form between them angles of 120 °.

As described by the patent EP1045221 these grooves each comprise a corrugation 37. As can be seen more clearly in FIG. figure 5 which shows an isolated flap 7, this corrugation 37 shares each groove in two rectilinear aligned portions 38.1 and 38.2 which are separated by another rectilinear portion 38.3 parallel to the previous ones. Rounded portions connect the linear portions. The amplitude of the corrugation is about 2 mm and its length about 4 mm.

Each groove cooperates with a rod 21 fixed relative to the projectile and more particularly each rod cooperates with two grooves of two adjacent flaps.

Thus the rod 21a guiding the groove 23a of the flap 7a and the groove 22b of the flap 7b.

The rod 21b guiding the groove 23b of the flap 7b and the groove 22c of the flap 7c.

Finally, the rod 21c guiding the groove 23c of the flap 7c and the groove 22a of the flap 7a.

Each flap 7 is held between two parallel surfaces or partitions delimiting a groove 17. Thus the flap 7a is disposed in the groove 17a, between the upper partition 15a and the next partition 15b. The flap 7b is disposed in the groove 17b, between the partitions 15b and 15c. The flap 7c is disposed in the groove 17c between the partition 15c and the bearing surface 16 of the body 13.

Such an arrangement of the shutters ensures the protection of the shutters and their mechanical resistance to the acceleration developed during firing of the projectile.

A game of the order of a tenth of a millimeter is provided between each flap 7 and the groove 17 which receives it, as well as between the rods 21a, 21b and 21c and the grooves in order to allow the flaps to move from their position. storage depicted in figure 3 to their deployed position represented in the figure 4 . We did not represent on the figure 4 the flaps 7 and the holding pieces 43. The partitions separating the flaps are not shown. However, the central portion 14 of the body 13 of the rocket has been positioned in dotted lines.

Each flap is made for example of sheet steel 2 mm thick and carries the two grooves 22, 23 for receiving the rods 21. The flaps may also be made of another material for example a light alloy (based on aluminum).

As described in the patent EP1045221 and more particularly visible at the figure 5 each flap has an outer profile 25 covering an arc of a circle whose diameter is substantially equal to the outer diameter of the rocket 3. figure 5 thus shows a flap 7 alone.

Each flap also has a notch 26 intended to allow the positioning of the flap around the central portion 14 of the body 13 of the rocket. For this purpose the indentation 26 comprises a hemicylindrical portion 27 of the same diameter as that of the central portion 14 and coaxial with the axis 20 thereof (that is to say also to the axis of the rocket and the projectile ). The hemicylindrical portion 27 of the indentation is connected to two flat surfaces 28 and 29 which are parallel to the grooves 22, 23.

A corrugation 40 is produced at the level of the flat surface 28 and a complementary recess 39 is arranged at the flat surface 29. These arrangements allow the lateral translation of the flap 7 with respect to the central portion 14 during the passage of the corrugations 37 by the stems 21.

As described by the patent EP1045221 , the corrugations of the grooves 22 and 23 make it possible to ensure braking of the opening movement of the flap 7. Indeed, when the rod 21 reaches the level of the corrugation 37, the clearance between the groove and the rod is distributed differently, the flap translates laterally with respect to the central portion 14, the groove rubs against the rod, thereby consuming energy and reducing the speed of movement of the shutter. The undulations thus constitute a means of slowing down the movement of deployment of the shutter. This reduces the impact of abutment of each flap against the guide rods at the end of the deployment movement, which increases the reliability of the device.

The indented shape of the flaps 7 also allows to obtain a maximum flap surface for minimal space in the folded position.

All flaps 7 here have the same structure and they comprise means that allow the locking of the shutters relative to each other in the folded position.

Thus, each flap 7 carries a hole 30, this hole is intended to receive, at the level of the only first flap 7a, the rod 31 of a pyrotechnic piston 32 (see FIG. figure 2 ).

This pyrotechnic piston is here a pyrotechnic retractor which is integral with the body 13 of the rocket. It comprises a gas generating composition which is electrically initiated by the control device 4 and which has the effect of causing the rod 31 to be pulled out of the hole 30. Such a pyrotechnic component is well known to those skilled in the art and it will not be described in more detail.

The rod 31 of the retractor ensures the locking of the first flap 7a in the folded position.

Each flap also carries a notch 33. The notch 33a of the first flap 7a is intended to cooperate with a first pin 34b carried by the second flap 7b to maintain the folded position thereof (see figure 3 ).

In a similar way, the second flap 7b carries a second notch 33b (in dotted lines figure 3 ) which is intended to cooperate with a second pin 34c carried by the third flap 7c to maintain the folded position thereof. We can refer to the patent EP1045221 for a more detailed description of this mutual blocking of shutters. The pins 34b, 34c are housed in holes 47. Only the flaps 7b and 7c carry a pin, the flap 7a is devoid of it.

In order to allow the pins 34b and 34c to be positioned in the notches 33a and 33b of the flaps 7a and 7b, the partitions 15b and 15c each comprise a clearance 48 which is delimited by two perpendicular planes. These clearances are visible at figure 3 with dots. A clearance is particularly visible at the figure 6 on which the partition 15b is shown. A single pyrotechnic piston 32 thus ensures the locking of all three components and prevents the deployment of these as a result of the centrifugal efforts exerted on them when firing the projectile.

The holding pins are constituted by small cylindrical rods mounted in the holes 47 made on the flaps.

The figure 3 shows the three flaps in their folded and locked position.

The section of the rocket was made to remove the upper partition 15a. Only the first component 7a is completely visible. The three rods 21a, 21b and 21c are cut. The second component 7b is hidden by the partition 15b. The third part is also hidden.

This figure shows how the different holding means cooperate with one another so as to ensure a locking of the three shutters.

It can thus be seen that, when the first flap 7a is immobilized by the rod 31 of the pyrotechnic piston introduced into the hole 30, the pin 34b of the second flap is positioned in the notch 33a of the first flap 7a, notch 33a which is parallel to the direction 24a and which is therefore cut by the direction 24b of deployment of the second component. The second component can not be deployed.

In a similar way, the pin 34c carried by the third flap 7c is positioned in the notch 33b of the second flap 7b (visible elements in dashed lines). The notch 33b is parallel to the direction 24b and is therefore cut by the direction of deployment 24c of the third component The third component can not open.

According to the invention, the notch 26 of each flap 7a, 7b and 7c comprises two end nozzles 41 which are each engaged in an impression 42 carried by a holding piece 43. These holding pieces 43 are all identical and are identified 43a, 43b and 43c on the figures 3 and 4 for distinguish the maintenance parts that are associated with each component.

Each holding piece 43 is connected to the rocket 3 by a rod 21a, 21b or 21c. It is positioned, just like the shutter it blocks, in the annular groove 17a, 17b or 17c.

Each holding piece 43 is constituted by a piece of steel sheet having substantially the same thickness as the flap considered.

Each holding piece 43a, 43b, 43c has an internal medial portion 44 which is engaged in the notch 26 of the flap in the folded position. This median portion 44 is extended by two wings 45. Each wing 45 has a cavity 42 receiving one of the nozzles 41 of the flap in question.

Each holding piece 43a, 43b, 43c finally has a circular outer profile 46 which extends the outer profile of the flap considered and closes the notch 26.

We see on figures 3 and 5 that the nozzles 41 have a trapezoidal profile. The wings 45 comprise imprints 42 which have a shape complementary to that of the nozzles 41.

The trapezoidal profile allows an unlocking without excessive efforts during the deployment of the flap 7.

When the flaps are in the folded position ( figure 3 ), the holding pieces 43a, 43b and 43c prevent the spacing of the nozzles 41 which would be caused by the action of the centrifugal forces. They thus prevent the opening of the indentation 26 which would cause jamming of the flap 7 with respect to its guide pins 21.

The invention thus makes it possible to make the operation of the braking device 6 reliable.

It is not necessary to immobilize in rotation the holding member relative to its rod 21. In the folded position, the flap 7 prevents the rotation of the holding part 43 associated therewith. In the deployed position, Limited pivoting movements of the holding piece 43 in the groove 17 do not matter.

It is possible to implement the invention with flaps 7 whose grooves 22, 23 are straight and have no corrugations 37. Such grooves are described by the patent. EP1045221 and it is unnecessary to describe them in more detail, the holding parts according to the invention being otherwise identical in this case to those previously described.

It is also possible to implement the invention with a rocket whose braking device comprises only two flaps which are deployed in opposite directions to one another. In this case the flaps will be further separated from each other by an intermediate partition secured to the body and which will receive a first flap on one side and a second flap on the other side. The flaps and the holding parts will then be housed in grooves delimited by the internal partition and by surfaces or surfaces of the rocket body which are parallel to this intermediate partition. The guide rods 21 will then be integral with this intermediate partition which will also carry the two holding pieces.

Claims (6)

Warhead rocket (3) for a gyro-stabilized artillery projectile, a rocket incorporating a device (6) for translational braking comprising at least two flaps (7) deployable radially on a trajectory so as to increase the aerodynamic drag of the projectile, each flap having at least two closed grooves (22,23) substantially parallel to a direction (24) perpendicular to the axis (20) of the rocket, each groove cooperating with a rod (21) which is fixed relative to a body (13) ) of the rocket, grooves disposed on either side of a notch (26) which is intended to allow the positioning of the flap (7) in the folded position around a central portion (14) of the body (13) of the rocket, rocket characterized in that the notch (26) of each flap comprises end nozzles (41) which are engaged in cavities (42) of complementary shapes which are carried by a holding piece (43) linked to the rocket (3). Warhead according to claim 1, characterized in that the holding piece (43) has an internal medial portion (44) which is engaged in the notch (26) of a flap (7) in the folded position, part median which is extended by two wings (45), each wing having a footprint (42) receiving one of the nozzles (41) of the flap. Warhead according to claim 2, characterized in that the holding piece (43) has a circular outer profile (46) which extends the outer profile of the flap (7). Warhead according to one of claims 1 to 3, characterized in that it comprises three flaps (7a, 7b, 7c) regularly distributed angularly, three rods (21a, 21b, 21c) also regularly distributed angularly guiding the different shutters, each rod also ensuring the maintenance of a holding piece (43a, 43b, 43c). Warhead rocket according to one of claims 1 to 4, characterized in that each flap (7a, 7b, 7c) is housed in a furrow (17a, 17b, 17c) of the body of the rocket, which groove is delimited by partitions (15a, 15b, 15c) or body surfaces (16) which are parallel to one another. Warhead rocket according to claim 5, characterized in that at least one partition (15) has a recess (48) allowing the passage of a pin (34) carried by a flap (7) arranged on one side of said partition (15), pin which engages in a notch (33) carried by another flap (7) disposed on the other side of said partition (15).

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