METHOD FOR REDUCING AN IMBALANCE OF A PROJECTILE SHELL

Abstract

The invention relates to a method for reducing an imbalance of a projectile shell. The projectile shell has a body (1) which has a recess (4). By this recess (4), the body is provided with an inner wall (2) and an outer wall (3). In addition, a mouth hole (6) is provided, which is connected to the recess (4). A central axis (5) is now calculated from the outer geometrical shape of the projectile shell and a measurement is then performed to ascertain an imbalance of the projectile shell. On the basis of the measured imbalance, modified axis (8) is then calculated in relation to the central axis (5), and the body (1) is rotated about the modified axis (8) on the basis of the calculated modified axis (8). As the body (1) is rotated in this way, the projectile shell is machined to eliminate the imbalance as far as possible.

Claims

1.-15. (canceled)

16. A method for reducing an imbalance in a projectile shell, with a body which has a recess, whereby the body has an inner wall and an outer wall, with a mouth hole which is connected to the recess, characterized in that a central axis is calculated from the external geometric shape of the projectile shell, that a measurement regarding imbalance of the projectile shell is then carried out, that, based on the imbalance, an axis that is modified in relation to the central axis is then calculated and that based on the calculated modified axis, the body is rotated about the modified axis, wherein the rotating body undergoes mechanical processing.

17. The method according to claim 16, wherein the mechanical processing of the rotating body is carried out as a machining turning process.

18. The method according to claim 16, wherein the body has a tail and that two center points on the tail and mouth hole are calculated by the modified axis.

19. The method according to claim 18, wherein two eccentric clamping surfaces are produced at the tail and the mouth hole, wherein the center points are arranged in the center of the eccentric clamping surfaces.

20. The method according to claim 19, wherein the eccentric clamping surfaces are produced by a milling process.

21. The method according to claim 16, wherein the body is clamped in a turning machine for rotation about the modified axis.

22. The method according to claim 16, wherein the modified axis and the central axis have a common center point in the center of the mouth hole.

23. The method according to claim 16, wherein the projectile shell is embodied as an axially symmetrical body.

24. The method according to claim 16, wherein the body is made in one piece.

25. The method according to claim 16, wherein the body consists of metal.

26. The method according to claim 24, wherein the body is manufactured in a forging process.

27. The method according to claim 16, wherein an inner body is calculated, namely as a solid body from the same material as the body, which corresponds to the volume of the recess.

28. The method according to claim 27, wherein the mass, the position of the center of gravity and the inertia tensor of the inner body are included to calculate the shifted axis.

29. The method according to claim 16, wherein the imbalance is measured while the body is rotating.

30. The method according to claim 16, wherein the projectile shell is used for a spin projectile.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0042] Further features can be seen in the attached drawings. They show

[0043] FIG. 1: cross-section of a projectile shell according to the invention;

[0044] FIG. 2: cross-section of a projectile shell with imbalance according to the invention;

[0045] FIG. 3: projectile shell clamped for rotation according to the invention.

DETAILED DESCRIPTION

[0046] FIG. 1 shows a projectile shell according to the invention, which usually consists of a body 1 made of metal and was manufactured in a forging process. For this purpose, the body 1 comprises an inner wall 2 and an outer wall 3. The inner wall 2 is formed by a recess 4, which comprises a similar geometric shape as the body 1.

[0047] The recess 4 creates an inner contour in the body 1, with the inner wall 2 as the boundary in the body 1. Due to the geometry of the body 1, it comprises a central axis 5, which also extends through the recess 4.

[0048] The projectile according to the invention further comprises a mouth hole 6 and a tail 7. The tail 7 forms a termination at the bottom of the projectile. The mouth hole 6 is arranged on the opposite side of the tail 7 and provides access to the recess 4.

[0049] The recess can be filled through the mouth hole 6, for example, or the projectile can be transported by means of a lifting device attached to the mouth hole.

[0050] According to the invention, a modified axis 8 is now calculated in FIG. 2. First, an inner body is calculated which corresponds to the volume of the recess 4 and is made of the same material as the body 1. Likewise, an outer body is calculated which corresponds to the geometry of the body 1, but is solid and comprises no recess 4.

[0051] Using the real body 1 and the calculated inner and outer bodies, the longitudinal main axis of inertia can now be calculated. To do this, the position of the center of gravity of the inner body is first calculated as well as the associated mass and the associated inertia tensor. The modified axis 8 is then derived from this.

[0052] The modified axis 8 is shifted in relation to the central axis 5, which can be seen in FIG. 2 by the offset (v1 and v2). The modified axis 8 is to be considered exemplary and runs differently for each projectile shell depending on the imbalance.

[0053] By means of the modified axis 8, center points 9 are calculated at the tail 7 and mouth hole 6, at which a rotation of the projectile shell is carried out. A center point, e.g. at the mouth hole, can also coincide with the center point of the central axis 5.

[0054] If the subsequent rotation of the body 1 is to be carried out on a turning machine, a clamping surface must now be created around each of the center points. This is preferably done by a milling process.

[0055] The body 1 is then rotated around the modified axis 8 to be machined.

[0056] Such a machining operation is shown in FIG. 3. Here the body 1 is clamped in a turning machine by means of the off-center clamping surfaces 10 arranged around the center points. After clamping, the body 1 is rotated around the modified central axis 8 and machined.

[0057] Such mechanical processing can be carried out by a machining method, e.g. by means of a turning process or milling process. However, the body 1 can also be machined by grinding or another material-removing method.

[0058] After the rotating body has been machined, the imbalance is minimized, at least to the extent that it lies within the specified tolerances. Additional grinding of the inner contour is completely omitted.

[0059] The present invention is not limited to the aforementioned features, but further embodiments are conceivable. For example, the body could comprise a different outer and inner contour. The only important thing for the method is that the inner body can be calculated from the known outer geometry and the measured imbalance. Furthermore, the recess can be filled with a penetrator instead of an effective agent. Finally, the imbalance could be measured by a rotation method.

REFERENCE SIGNS

[0060] 1 body [0061] 2 inner wall [0062] 3 outer wall [0063] 4 recess [0064] 5 central axis [0065] 6 mouth hole [0066] 7 tail [0067] 8 modified axis [0068] 9 center points [0069] 10 eccentric clamping surfaces