BULLET AND AMMUNITION

Description

[0001] The invention relates to a projectile having a projectile casing and an ogive placed on the projectile casing, wherein the ogive and the projectile casing are connected to each other by a threaded profile connection.

[0002] Furthermore, the invention relates to ammunition, in particular artillery ammunition, comprising such a projectile.

[0003] Artillery ammunition is usually fired from mobile weapon systems. These weapon systems are dimensioned in different calibers and, due to their weight, can only be moved with the help of vehicles.

[0004] In the past, artillery ammunition consisted of a one-piece warhead and a fuze. In the case of a cargo case, the warhead consists of at least two parts (case and base), and often three parts (ogive, case, base). The warhead can be designed variably and therefore fulfill different tasks. Depending on these tasks, projectiles can be classified, for example, into explosive, nuisance, flare, and smoke projectiles. A classification is also made based on their basic function, into projectiles with and without ejection.

[0005] Non-ejecting projectiles, such as conventional explosive projectiles, in which a head fuse causes the projectile casing to fragment in the target area, and the casing produces ballistically effective fragments upon detonation of an inserted explosive charge. A fragmentation projectile with a tracer charge is disclosed, for example, in DE 3919314 A1.

[0006] In contrast, ejection projectiles, often referred to as cargo projectiles, have a carrier shell and an integrated ejection system that ejects one or more secondary units into the target area. The effect of the secondary unit is often controlled by a delay element and only occurs after ejection. Well-known examples include flare and smoke projectiles, as disclosed, for example, in DE 10 2007 057 184 A1.

[0007] There are solutions for training ammunition that aim to recreate the signature of a regular explosive projectile, for example, regarding smoke, bang, and flash effects, for the purpose of training operations by military forces. For example, DE 10 2011 010 183 Al discloses a known internal structure of an explosive projectile with a single-piece casing within a multi-piece cargo projectile casing.

[0008] Artillery ammunition is typically propelled by a multi-stage, adjustable propellant charge (e.g., the 155mm modular DM72 / DM 82 / DM 92 propellant charge). There are various propellant charge shapes, but the charge weight can always be adjusted to the required trajectory / distance.

[0009] During the combustion of the propellant charge, the artillery ammunition is accelerated by the almost explosive and rapidly expanding combustion gases.

[0010] For extended-range cargo projectiles with a required high payload (smoke / illuminators, etc.), projectile casings with slim contours in the ogive area and a large internal volume are used. This requires a thin wall thickness of the projectile casing.

[0011] In order to avoid a complex forging process in the production of the bullet casing and to simplify the internal machining of the bullet contour, these bullet casings are usually constructed in several parts.

[0012] Particular attention is paid to the connection between the front ogive and the projectile casing or the central part of the projectile, as the slim ogive contour and the requirement for a high payload mean that only limited space is available for connecting these components. This connection is typically achieved using single-start fine threads.

[0013] Due to the demand from customers for payload-optimized, long-range projectiles, considerable effort is put into production regarding the strength of the raw material (high-strength steels) and the tightening torque of the components to be joined, the ogive and projectile casing. Furthermore, considerable effort is put into bonding the components to prevent slippage during spin acceleration.

[0014] These challenges in joining the multi-part yet slim projectile casing have been addressed through various measures. Firstly, high-strength steels are used to allow the necessary very high tightening torques between the components. Furthermore, the bonding points were cleaned in advance, which involved considerable effort, and a very homogeneous bond was achieved using two-component epoxy adhesives. In addition, friction torque-enhancing measures (sandblasting, friction coatings) were applied to the end faces of the components to be joined, and very tight manufacturing tolerances were selected for the threads.

[0015] The trajectory of artillery projectiles is typically spin-stabilized. Since the spin is clockwise, the attachments mounted in front of the projectile's guide band (in this case, the ogive) are provided with a right-hand thread and are installed with a high torque to achieve clamping of the components to one another. This high torque must be generated using appropriate devices. The torque to be applied depends on the moments of inertia of the components and the maximum spin acceleration.

[0016] Since the torque during spin acceleration is very often higher than the torque that can actually be applied during assembly, the threaded connection must be manufactured very precisely and bonded completely homogeneously using two-component adhesives.

[0017] The friction coefficient of the interfaces (front sides) of the components must be increased by suitable measures so that loosening of the threaded connections can be further inhibited, although friction coatings are partially removed or smoothed again during assembly due to the relative movements to one another.

[0018] Depending on the bullet type and the firing load, additional positive pinning / toothing may also be necessary.

[0019] To be able to apply the high torques while simultaneously handling fragile projectile casing cross-sections, the steel raw material must meet stringent requirements regarding tensile strength, impact strength, and purity. This is only possible by limiting undesirable alloying components (such as sulfur and phosphorus) and precisely maintaining the proportion of desirable alloying components. The assembly devices must be designed to be extremely robust to deliver the torques. Despite all these measures, the additional costs described above are sometimes borderline for even minor defects and require complex inspections.

[0020] From DE 301 307 C a multi-part artillery projectile is known in which the ogive and the projectile casing are connected to each other by a fine thread.

[0021] From DE 1 086 153, an annular coupling element for missiles made of epoxy resin is known, which has a multi-start thread on one side and a fine thread on the opposite side.

[0022] The multi-start thread, together with a mating thread on a guided missile's payload nose, forms a quick-release fastener. The fine-pitch thread is used for center of gravity adjustment.

[0023] The invention is therefore based on the object of creating a connection between the bullet casing and the ogive which allows the technological effort for producing a connection between the ogive and the bullet casing to be reduced.

[0024] This object is achieved by the features of claim 1. Advantageous embodiments and further developments are the subject of the subclaims.

[0025] According to the invention, a spin-stabilized projectile is provided with a projectile casing and an ogive attached to the projectile casing. The ogive and the projectile casing are connected to each other by a threaded profile connection. The threaded profile connection is designed as a multi-start thread having several thread turns.

[0026] The invention is primarily based on the use of a threaded profile connection between the ogive and the bullet casing (or a central bullet section or other bullet casing components). The threaded profile connection is multi-threaded, i.e., it has several threads running side by side and engaging simultaneously.

[0027] Furthermore, the thread profile connection has a large lead angle and thus a large thread pitch ((P = -< rr* d2* tan (ap)) in order to reduce the very high screwing forces (screwing force = (force * lever arm / pitch) - friction forces) that usually occur with small thread pitches. This is achieved by the multiple threads. The greater the pitch of the thread profile, the lower the screwing force that occurs during the launch acceleration of the bullet and thus the force that pushes both components (ogive and bullet casing) apart.

[0028] This provides a thread profile connection whose manufacturing effort, particularly with regard to the required accuracies and tolerances, is reduced.

[0029] Furthermore, the design of the thread profile connection according to the invention eliminates the need for ultra-high-strength steels. Ultra-high-strength steels were previously required for the production of the fine threads previously used. This further reduces the manufacturing effort, as the machining effort required for the steels is reduced. Furthermore, material costs are reduced.

[0030] In its design, the thread profile of the thread profile connection is a stable, solid and flat thread profile which, due to its design, is able to absorb large forces.

[0031] The advantages of the projectile according to the invention further lie in the fact that it reliably withstands increased spin accelerations of future and current (artillery) weapon systems.

[0032] Furthermore, the internal shell bracing is reduced by redirecting the force flow. Due to the multi-thread design, a particularly high pitch angle can be selected, which positively influences this redirection of force flow.

[0033] The inventive design of the thread profile connection prevents thread failure because the thread profile connection has a stable interface geometry.

[0034] Furthermore, the bullet according to the invention and its threaded profile connection achieve a reduction in assembly time and costs, as multi-component bonding and prior cleaning and degreasing of the threaded profile connection are no longer necessary. This was previously necessary when using conventional threads, especially fine threads, to connect the ogive and the bullet casing.

[0035] Furthermore, the manufacturing effort in producing the thread profile connection can be reduced by eliminating the need for friction coatings or changes in the surface quality during the production of the thread profile connection.

[0036] According to the invention, the ogive can be designed with an external thread and the bullet casing with an internal thread, so that the ogive can be screwed into the bullet casing.

[0037] Alternatively, the ogive can be designed with an internal thread and the bullet casing with an external thread.

[0038] With regard to the multiple threads, for example, the thread profile connection can be provided with at least three threads. However, it can also be provided that the thread profile connection has 4, 5, 6, 7, 8, 9, or 10 threads.

[0039] Preferably, the thread profile connection has between 4 and 7 threads.

[0040] Preferably, the projectile may be an artillery projectile, in particular as part of an artillery ammunition.

[0041] Furthermore, according to the invention, ammunition is provided which comprises such a projectile or a projectile according to the further development described below.

[0042] The projectile can be a flare, smoke, blast, flash, signal, practice or explosive projectile.

[0043] The ammunition may be artillery ammunition.

[0044] In an embodiment, the ogive can have an ogive thread profile and the bullet casing can have a bullet casing thread profile to form the thread profile connection.

[0045] The geometry of the bullet casing thread profile may differ from the geometry of the ogive thread profile. However, both components can always be joined together.

[0046] Furthermore, it can be provided that the bullet casing thread profile has flat flank tips and / or the ogive thread profile has flat flank tips.

[0047] In an embodiment, the flank tips of the bullet casing thread profile and / or the ogive thread profile are designed to correspond to the flank tips of a flat thread or a trapezoidal thread.

[0048] It may be provided that the bullet casing thread profile has a rounding in the transition between the flank of the bullet casing thread profile and the flank tip.

[0049] Furthermore, it can be provided that the ogive thread profile has a rounding in the transition between the flank of the ogive thread profile and the flank root of the ogive thread profile.

[0050] The curves of the bullet casing thread profile and the ogive thread profile correspond to each other and are assigned to each other when assembled.

[0051] Alternatively, the arrangement of the curves on the bullet casing thread profile and the ogive thread profile can also be reversed on the respective thread profiles, as long as they are assigned to each other accordingly.

[0052] The projectile may be provided with a threaded profile connection on the ogive and / or the projectile casing, preferably each thread of the ogive and / or the projectile casing, having an insertion bevel. This improves the mountability of the ogive on the projectile casing.

[0053] It can be provided that the threaded profile connection has a first locking device.

[0054] By forming such a positive locking device, "overtightening" of the thread profile connection is prevented.

[0055] These locking devices, which include form-fitting elements on the front, prevent stress-dependent deformations.

[0056] It can further be provided that, in order to form the first locking device, the ogive has a first locking element and the projectile casing has a first locking recess.

[0057] The projectile can further be designed such that the threaded profile connection has a second locking device.

[0058] By forming such a positive locking device, "overtightening" of the thread profile connection is prevented.

[0059] It can be provided that, to form the second locking device, the projectile casing has a second locking element and the ogive has a second locking recess.

[0060] Furthermore, as an alternative or in addition to the first and / or second locking device, the bullet casing and / or the ogive can have rings inserted on the front side which prevent radial deformation of the thread profile connection, in particular of the ogive thread profile and / or the bullet casing thread profile.

[0061] In a design, the thread profile connection can have a pitch angle of 30° to 45°.

[0062] Preferably, the flank angles of the αp of the thread profile are very flat.

[0063] In an embodiment, it can be provided that the ogive thread profile and / or the bullet casing thread profile, in particular the entire thread profile connection, has a flank angle α of 4° to 20°, preferably of 5° to 17°, in particular of 14°.

[0064] This ensures that the thread flanks cannot slide against each other under high axial and radial loads, thus preventing the thread from being over-tightened.

[0065] The bullet can also be secured with front-face screws to secure the connection between the ogive and the bullet casing.

[0066] The projectile may further comprise at least one axial frontal pinning as additional securing of the screwed ogive.

[0067] Furthermore, the projectile may comprise at least one radial frontal pin as additional security for the screwed ogive.

[0068] Furthermore, instead of or in addition to the first and / or second locking device, a friction ring can be formed, as described in the parallel application Geschoss und Munition, the inventors Dau, Weise and Borchert, the content of which is incorporated herein by reference.

[0069] In addition, the surfaces of the first and / or second locking device and / or the friction ring can be roughened in order to have an increased coefficient of friction compared to an unroughened surface.

[0070] The ammunition may be designed to be a flare, smoke, blast, flash, signal, practice or explosive projectile.

[0071] Furthermore, according to another aspect of the application, it can be provided that a threaded profile connection as described above in connection with the projectile and in particular the connection between the projectile and the ogive is generally designed for use on a projectile. This makes it possible for such a threaded profile connection to be provided at other joints of the projectile and for components to be joined therewith.

[0072] Further details and advantages of the invention will become apparent from the following exemplary embodiments explained with reference to figures.

[0073] They show: Fig. 1 is a schematic representation of a first embodiment of a projectile according to the invention, wherein the projectile casing is shown partially in section; Fig. 2 is a further schematic representation of the first embodiment of the projectile according to the invention, wherein the projectile casing is shown partially in section; Fig. 3 is a schematic representation of the first embodiment of the projectile according to the invention; Fig. 4 is a schematic sectional representation of the first embodiment of the projectile according to the invention; Fig. 5 is a schematic sectional representation of a region of the projectile casing thread profile of the first embodiment of the projectile according to the invention; and Fig. 6 is a schematic representation of a region of the ogive thread profile of the first embodiment of the projectile according to the invention.

[0074] Fig. 1 shows a schematic sectional view of a projectile 1, wherein the projectile is shown in an assembled state. Fig. 2 shows a further schematic representation of the first embodiment of the projectile 1 according to the invention, with the projectile casing 2 shown partially in section. The projectile 1 is shown here in an unassembled state.

[0075] The projectile 1 comprises a projectile casing 2 and an ogive 4 placed on the projectile casing 2. The ogive 4 and the projectile casing 2 are connected to each other by a threaded profile connection 6.

[0076] As in the Fig. 1 and the Fig. 2 As can be seen, the thread profile connection 6 has several threads.

[0077] To form the thread profile connection 6, the ogive 4 has an ogive thread profile 6.2 and the bullet casing 2 has a bullet casing thread profile 6.1. According to the Fig. 1 and 2In the first embodiment shown, the ogive thread profile 6.2 is designed as an external thread. The bullet casing thread profile 6.1 is designed as an internal thread.

[0078] Fig. 3 shows a schematic representation of the first embodiment of the projectile 1 according to the invention. The ogive 4 and the ogive thread profile 6.2 of the thread profile connection 6 are shown in an enlarged view. The ogive thread profile 6.2 has a pitch angle ap of 30° to 45°.

[0079] Even if in the Fig. 3 Not shown, the bullet casing thread profile 6.1 has a pitch angle of 30° to 45°. The thread profile connection 6 thus has a pitch angle of 30° to 45°.

[0080] Fig.4 shows a schematic sectional view of the first embodiment of the projectile 1 according to the invention. The projectile is, as in Fig. 1 , shown in the assembled state.

[0081] As from the Fig. 4 As can be seen, the geometry of the bullet casing thread profile 6.1 differs from the geometry of the ogive thread profile 6.2. However, the bullet casing thread profile 6.1 and the ogive thread profile 6.2 can still be joined.

[0082] The bullet casing thread profile 6.1 shows how well Fig. 5 can be seen, has flat flank tips 6.1sp. The ogive thread profile 6.2sp also has, as can be seen in Fig. 6 can be seen, flat flank tips 6.2sp. As can be seen from the Fig. 4 As can be seen, both threads are designed in the manner of a trapezoidal thread profile or a flat thread profile.

[0083] From the Fig. 4 It can be seen that the threaded profile connection 6 on the ogive 4 and / or on the projectile casing 2 has at least one insertion bevel 2E, 4E.

[0084] Even if the Fig. 4not visible, preferably each thread of the ogive 4 and / or the bullet casing 2 (or of the ogive thread profile 6.2 and the bullet casing profile 6.1) has an insertion bevel 2E, 4E. The respective insertion bevels are realized in a manufacturing process such that a chamfer is created on the cylindrical portion of the bullet casing 2 and / or the ogive 4 in a processing step before the threads are manufactured (e.g. by broaching).

[0085] The threaded profile connection 6 has a first locking device 8. To form the first locking device 8, the ogive 4 has a first locking element 12, and the projectile casing 2 has a first locking recess 14.

[0086] The first locking element 12 is arranged at a tip of the ogive thread profile 6.2. The first locking recess 14 is arranged at the base of the bullet casing thread profile 6.1. According to the first embodiment, the first locking element 12 can be designed as a locking lug. The first locking recess 14 can be designed as a locking groove.

[0087] In the assembled state of floor 1, which is in Fig. 4 As shown, the first locking element 12 and the first locking recess 14 interact and prevent the threaded profile connection 6 from being pushed apart and overtightened.

[0088] The threaded profile connection 6 further comprises a second locking device 10. To form the second locking device 10, the projectile casing 2 comprises a second locking element 16, and the ogive 4 comprises a second locking recess 18.

[0089] The second locking element 16 is arranged at a tip of the bullet casing thread profile 6.1. The second locking recess 18 is arranged at the base of the ogive thread profile 6.2. According to the first embodiment, the second locking element 16 can be designed as a locking lug. The second locking recess 18 can be designed as a locking groove.

[0090] In the assembled state of floor 1, which is in Fig. 4 As shown, the second locking element 16 and the second locking recess 18 interact and prevent the threaded profile connection 6 from being pushed apart and overtightened.

[0091] According to Fig. 5 A section of the bullet casing thread profile 6.1 is shown in a sectional view. The bullet casing thread profile 6.1 has a rounded portion 6.1R at the transition between the flank of the bullet casing thread profile 6.1F and the flank tip 6.1sp.

[0092] The flank tip 6.1 Sp and the flank root 6.1 GR of the bullet casing thread profile 6.1 are flat and each have a flat area, which are designed like a flat or trapezoidal thread.

[0093] The bullet casing thread profile 6.1 preferably has a flank angle α of 4° to 20°, preferably of 5° to 17°, in particular of 14°.

[0094] According to Fig. 6 A section of the bullet casing thread profile 6.2 is shown in a sectional view. The ogive thread profile 6.2 has a rounding 6.2 R at the transition between the flank of the ogive thread profile 6.2 F and the flank root of the ogive thread profile 6.2 GR.

[0095] The flank crest 6.2 SP and the flank root 6.2 GR of the ogive thread profile 6.2 are flat and each have a flat area, which are designed like a flat or trapezoidal thread.

[0096] The ogive thread profile 6.2 has a flank angle α of 4° to 20°, preferably of 5° to 17°, in particular of 14°.

[0097] Thus, the ogive thread profile 6.2 and / or the bullet casing thread profile 6.1 have a flank angle α of 4° to 20°, preferably of 5° to 17°, in particular of 14°.

[0098] The projectile can, for example, be an artillery shell. Such a projectile charge can include, for example, one or more flares or smoke canisters. However, other charges are also conceivable, which can be used to create flares, smoke, blast, flash, signal, practice, or explosive projectiles.

[0099] Preferably, the Figures 1 to 6 The projectile 1 shown is an artillery projectile. This can be designed, for example, as a flare, smoke, blast, flash, signal, training, or explosive projectile.

[0100] To the extent that the above disclosure refers to a projectile, it equally applies to ammunition comprising such a projectile. The ammunition may preferably be artillery ammunition. LIST OF REFERENCE SYMBOLS

[0101] 1Bullet 2Bullet casing 2 E Lead-in chamfer of the bullet casing 4Ogive 4 E Lead-in chamfer of the ogive 6Thread profile connection 6.1Bullet casing thread profile 6.1 F Flank of the bullet casing thread profile 6.1 GR Flank root of the bullet casing thread profile 6.1 R Rounding of the bullet casing thread profile 6.1 SP Thread crest of the bullet casing thread profile 6.2Ogive thread profile 6.2 F Flank of the ogive thread profile 6.2 GR Flank root of the ogive thread profile 6.2 R Rounding of the ogive thread profile 6.2 SP Thread crest of the ogive thread profile 8First locking device 10Second locking device 12First locking element 14First locking recess 16Second locking element 18Second locking recess αFlank angle αpHelix angle PSteep

Claims

1. Projectile (1) which is spin-stabilized, comprising a projectile casing (2) and an ogive (4) placed on the projectile casing (2), the ogive (4) and the projectile casing (2) being interconnected by a thread profile connection (6), characterized in that the thread profile connection (6) is designed as a multi-start thread having a plurality of thread turns.

2. Projectile (1) according to claim 1, characterized in that in order to form the thread profile connection (6), the ogive (4) has an ogive thread profile (6.2) and the projectile casing (2) has a projectile casing thread profile (6.1).

3. Projectile (1) according to claim 2, characterized in that the geometry of the projectile casing thread profile (6.1) deviates from the geometry of the ogive thread profile (6.2).

4. Projectile (1) according to claim 2 or claim 3, characterized in that the projectile casing thread profile (6.1) has flat flank tips (6.1sp) and / or the ogive thread profile (6.2sp) has flat flank tips (6.2sp) .

5. Projectile (1) according to any of claims 2 to 4, characterized in that the projectile casing thread profile (6.1) has a rounding (6.1R) in the transition between the flank of the projectile casing thread profile (6.1F) and the flank tip (6.1sp).

6. Projectile (1) according to any of claims 2 to 5, characterized in that the ogive thread profile (6.2) has a rounding (6.2R) in the transition between the flank of the ogive thread profile (6.2F) and the flank base of the ogive thread profile (6.2GR).

7. Projectile (1) according to any of the preceding claims, characterized in that the thread profile connection (6) has an insertion bevel (2E, 4E) on the ogive (4) and / or on the projectile casing (2), preferably each thread turn of the ogive (4) and / or the projectile casing (2).

8. Projectile (1) according to any of the preceding claims, characterized in that the thread profile connection (6) has a first locking device (8).

9. Projectile (1) according to claim 8, characterized in that in order to form the first locking device (8), the ogive (4) has a first locking element (12) and the projectile casing (2) has a first locking recess (14).

10. Projectile (1) according to any of claims 8 or 9, characterized in that the thread profile connection (6) has a second locking device (10).

11. Projectile (1) according to claim 10, characterized in that in order to form the second locking device (10), the projectile casing (2) has a second locking element (16) and the ogive (4) has a second locking recess (18).

12. Projectile (1) according to any of the preceding claims, characterized in that the thread profile connection (6) has a lead angle (ap) of 30° to 45°.

13. Projectile (1) according to any of the preceding claims, characterized in that the ogive thread profile (6.2) and / or the projectile casing thread profile (6.1) has a flank angle (a) of 4° to 20°, preferably of 5° to 17°, in particular of 14°.

14. Ammunition comprising a projectile (1) according to any of claims 1-13.

15. Ammunition according to claim 14, characterized in that the ammunition is artillery ammunition.

16. Ammunition according to claim 14 or claim 15, characterized in that the projectile is a flare, mist, smoke, bang, flash, signal, practice or explosive projectile.