Tail assembly of a guided fin-stabilized projectile

Abstract

The tail assembly (10) is connected to the rear of the main body (2) of the projectile (1) and includes a fixed part (12) that defines a longitudinal axis (XX). There is a movable part (14) which has multiple stabilizing fins (16), is attached to the rear of the fixed part (12), and is freely rotatable about the longitudinal axis (XX) relative to the fixed part (12). The movable part (14) is axially movable relative to the fixed part (12) between a contact state in which the fixed part (12) and the movable part (14) are in axial contact with each other and a separated state in which the fixed part (12) and the movable part (14) are separated in the axial direction and a peripheral gap (G) is defined between them. There is also a group of elastic parts (18) that attempt to hold the movable part (12) in the separated state.

Description

Technical Field

[0001] The present invention relates to a tail assembly of a guided projectile.

Background Art

[0002] In the projectile industry, various types of tail assemblies are known.

[0003] For example, in a guided projectile using canard fins, the tail assembly is typically utilized to provide aerodynamic stability and includes a fixed part and a movable part having a plurality of stabilizing fins. The movable part is generally attached to the rear and is freely rotatable relative to the fixed part about the longitudinal axis defined by the fixed part.

[0004] In a projectile equipped with a tail assembly manufactured according to the prior art, it is generally necessary to reduce the friction between the fixed part and the movable part as much as possible. In fact, during flight along the trajectory towards the target, the movable part generally rotates at high speed. Therefore, an axial peripheral gap is usually left between the fixed part and the movable part of the tail assembly so that when the projectile flies towards the target, the movable part can rotate freely with significantly less friction and effectively stabilize the following trajectory.

[0005] However, such tail assemblies are plagued by several drawbacks.

[0006] One drawback is that when a projectile equipped with a tail assembly according to the prior art is fired from the barrel of a firearm, gases at high temperature (e.g., about 2700°K) and high pressure (e.g., 4000 bar) are generated. Due to the presence of the peripheral gap between the fixed part and the movable part, such gases can flow into the tail assembly, damaging the components of the tail assembly and posing a risk to the flight stability of the projectile.

Summary of the Invention

[0007] One object of the present invention is to provide a tail assembly that can overcome the above-mentioned and other drawbacks of the prior art.

[0008] According to the present invention, the above and other objectives are realized by a tail assembly having the features described in the appended independent claims. The tail assembly thus conceived is capable of maintaining separation from the fixed part during the flight of the projectile while simultaneously preventing the inflow of high-temperature, high-pressure gases generated in the barrel during projectile firing into the tail assembly. More specifically, the "normal" state of the tail assembly is separated, as the elastic components attempt to keep the movable part axially separated from the fixed part. Conversely, when a projectile is fired through the barrel of the artillery system, the movable part receives a large axial thrust in the opposite direction to the elastic force of the elastic components, switching from separated to contact. Thus, the fixed and movable parts are "coupled," and the peripheral gap is eliminated, significantly reducing the potential adverse effects of unwanted inflow of gases generated during firing. Subsequently, as the projectile flies along its trajectory to the target, the axial thrust generated in the movable part within the barrel ceases to act, and the elastic components become free, returning the movable and fixed parts to separated, enabling low-friction mutual rotation.

[0009] The attached claims are an integral part of the technical teachings provided in the detailed description of the invention below. In particular, the attached dependent claims define several preferred embodiments of the invention, including several optional technical features.

[0010] Further features and advantages of the present invention will become apparent based on the following detailed description provided herein, in particular with reference to the accompanying drawings outlined below, and merely as non-limiting examples. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of a projectile including a tail assembly obtained according to an exemplary embodiment of the present invention. [Figure 2] Figure 1 is a partial cross-sectional perspective view of the tail assembly. [Figure 3] Figure 2 is an axial or longitudinal cross-sectional view of the tail assembly. In this figure, the fixed and movable parts of the tail assembly, shown in contact with each other, can be seen. [Figure 4] This is a magnified view of the detail separated by line IV in Figure 3. [Figure 5] Figure 2 is an axial or longitudinal cross-sectional view of the tail assembly. Unlike Figure 3, the fixed and movable parts of the tail assembly are shown separated. [Figure 6] This is a close-up view of the details separated by line VI in Figure 5. [Figure 7] This is an enlarged view of the tail assembly shown in the preceding figure, in the axial or longitudinal direction, showing the group of elastic components and connecting components interposed between the fixed part and the movable part. [Figure 8] This is an axial or longitudinal enlarged view of the tail assembly shown in the preceding figure, illustrating further details of the connecting components interposed between the fixed and movable parts.

[0012] For completeness, the following is a list of alphanumeric reference codes and names used herein to identify the parts, elements, and components shown in the diagram outlined above. 1 projectile 2 Main unit 2a front 2b Chubu 3 Canard Fins 10. Tail Assembly 12 Fixed part 14 Moving parts 16 stabilizing fins 18 Elastic component group 19 Disc springs 20 flanges 22 Shoulder end 24 Connecting Components 26 sleeves 28 Bearings 28a-b Ring structure 30 Rolling member 32 Main part 34 Stem 35 Annular groove 36 Jacket 38 Annular body 40 Tubular body 42 Stop ring 44 Spacer disk 46 Guide elastic member 48 Additional bearing 52 Fixed ring nut X-X Longitudinal axis G Peripheral gap

Best Mode for Carrying Out the Invention

[0013] Referring to FIG. 1, reference numeral 1 generally indicates a projectile, for example, a projectile using canard fins 3. The projectile 1 is aerodynamically stabilized by a tail assembly 10 obtained according to an exemplary embodiment of the present invention.

[0014] The projectile 1 comprises a body 2 of a type known per se. In the embodiment shown herein, the body 2 has a substantially elongated shape and comprises a front portion 2a and a middle portion 2b coupled to the front portion 2a. The front portion 2a is tapered, and the middle portion 2b has a generally cylindrical shape with a circular cross-section.

[0015] In the illustrated embodiment, the projectile 1 preferably comprises canard fins 3 attached to the body 2, and the fins can be oriented in a controlled manner with respect to the body 2. The canard fins 3 are shown to be attached to the middle portion 2b near the front portion 2a. However, it will be apparent to those skilled in the art that the canard fins 3 can be attached at any position on the body 2, whether at the front portion 2a or the middle portion 2b.

[0016] In the illustrated embodiment, the projectile 1 is also advantageously sub-caliber, for example, a sabot type. In other words, the projectile 1 includes a casing (not shown), also known in the industry as a "sabot," which is used to increase the outer diameter of the body 2 to match the inner diameter of the barrel of the artillery piece in which the projectile 1 will be housed before firing. Typically, the sabot is mounted around at least a portion of the middle section 2b.

[0017] In the illustrated embodiment, the canard fins 3 are non-retractable and protrude radially outward from the main body 2, both when the projectile 1 is inserted into the barrel of the artillery piece and when the projectile 1 is launched and flying along a trajectory toward the target.

[0018] The tail assembly 10 is attached to the rear of the main body 2 of the projectile 1, particularly to the rear of the middle section 2b.

[0019] The structure and components of the tail assembly 10 are shown in more detail with reference to Figures 2-7.

[0020] The tail assembly 10 includes a fixed part 12 that connects to the rear of the main body 2 (particularly the middle part 2b) of the projectile 1, defining the longitudinal axis XX. In the following detailed description, terms or expressions such as “axial” and “in the axial direction,” “radial” and “radial direction,” “inside” and “outside” refer to the longitudinal axis XX.

[0021] The tail assembly 10 further includes a movable part 14 attached to the rear of the fixed part 12, which has multiple stabilizing fins 16 and rotates freely relative to the fixed part 12 about a longitudinal axis XX. In particular, the longitudinal axis XX of the tail assembly 10 advantageously coincides with the longitudinal axis of the projectile 1.

[0022] As can be particularly seen in Figures 3 to 6, the movable part 14 is axially movable relative to the fixed part 12 between a contact state (shown in Figures 3 and 4) and a separated state (shown in Figures 5 and 6).

[0023] In the contact state, the fixed part 12 and the movable part 14 are in contact with each other in the axial direction. In contrast, in the separated state, the fixed part 12 and the movable part 14 are separated in the axial direction, and a peripheral gap G is defined between them.

[0024] The tail assembly 10 further comprises a group of elastic components 18 that attempt to hold the movable portion 14 in the separated state. For example, the group of elastic components 18 comprises a plurality of disc springs 19 stacked axially or filled in the longitudinal axis XX direction. However, as will be apparent to those skilled in the art, in further modified embodiments not shown herein, the group of elastic components may consist of only one disc spring. It is also conceivable to replace the disc spring(s) with one or more different springs, such as compression springs.

[0025] From the above perspective, the separated state corresponds to the practical "normal" state assumed by the tail assembly 10, in which case the fixed part 12 supported by the movable part 14 rotates about the longitudinal axis XX due to the peripheral gap G, thereby reducing friction between the two. Conversely, the contact state corresponds to a state in which the tail assembly 10 is subjected to external stress, causing the movable part 14 to contact the fixed part 12 in the axial direction against the action of the elastic component group 18.

[0026] From a particularly operational standpoint, the contact condition occurs when the projectile 1 (to which the tail assembly 10 is attached) is fired through the barrel of the artillery piece. In fact, when firing occurs, the projectile 1 undergoes rapid acceleration, which presses the movable part 14 toward the fixed part 12, overcoming the reaction force of the elastic component group 18. In this situation, the absence of a peripheral gap G substantially prevents gases generated during firing from flowing into the tail assembly 10 and damaging its components.

[0027] When firing occurs and the projectile 1 leaves the barrel, the elastic component group 18 pulls the movable part 14 axially away from the fixed part 12, and the separated state is re-established. In this way, as the projectile flies along its trajectory to the target, the peripheral gap G allows the movable part 14 to rotate with reduced friction relative to the fixed part 12 without compromising the stabilization of the projectile.

[0028] Preferably, the fixed portion 12 includes a flange 20 located radially outward along the longitudinal axis XX. The movable portion 14 includes a shoulder end 22 that cooperates with the flange 20 to define a peripheral gap G. The shoulder end 22 (which defines the movable annular surface) is configured to abut axially against the flange 20 (which defines the corresponding fixed annular surface) in the contact state, and to move axially away from the flange 20 to form a peripheral gap G in the separated state.

[0029] Referring to Figure 7, the tail assembly 10 shown in the separated state preferably includes a group of connecting parts 24 that connect the fixed part 12 to the movable part 14. The group of connecting parts 24 allows the movable part 14 to rotate freely relative to the fixed part 12 about the longitudinal axis XX. At the same time, the group of connecting parts 24 also allows the movable part 14 to slide freely relative to the fixed part 12 along the longitudinal axis XX.

[0030] In the illustrated embodiment, the connecting component group 24 can be translated integrally with the movable part 14 relative to the fixed part 12 in the direction of the longitudinal axis XX.

[0031] In the illustrated embodiment, referring to Figure 7, the elastic component group 18 is interposed axially between the connecting component group 24 and the fixed portion 12. In particular, the elastic component group 18 is pressed against the connecting component group 24 at one axial end and against the fixed portion 12 at the opposite axial end. As an alternative or combination to the above, in some modified embodiments (not shown), the elastic component group may be interposed between the fixed portion and the movable portion.

[0032] In the illustrated embodiment, the connecting component group 24 is slidably mounted on the fixing portion 12 along the longitudinal axis XX and includes a sleeve 26 whose rotation relative to the fixing portion 12 about the longitudinal axis XX is locked.

[0033] In the illustrated embodiment, the connecting component group 24 comprises a plurality of bearings 28 that connect the movable part 14 and the sleeve 26 in rotation around the longitudinal axis XX. In particular, there are pairs of bearings 28 stacked in the axial direction or filled in the direction of the longitudinal axis XX. Each of the bearings 28 is preferably a rotary bearing and, in particular, has a radially inner annular structure 28a fixed to the sleeve 26 and a radially outer annular structure 28b fixed to the movable part 14. A plurality of rolling members 30, such as balls, are interposed radially between the annular structures 28a and 28b.

[0034] Thus, when the projectile 1 is fired through the barrel, the movable part 14 and the connecting parts group 24, including the sleeve 26 and bearing 28, overcome the reaction force of the disc spring 19 and move integrally with respect to the fixed part 12 along the longitudinal axis XX. Therefore, the shoulder end 22 of the rolling member 14 comes into contact with the flange 20 of the fixed part 12.

[0035] Subsequently, as projectile 1 is launched from the barrel and flies toward the target, the disc spring 19 pushes the movable part 14, the sleeve 24 of the connecting parts group 24, and the bearing 28 together, translating them relative to the fixed part 12. This translational motion also occurs along the longitudinal axis XX, but at this point it is in the opposite direction, pulling away the shoulder end 22 of the movable part 14 and defining a peripheral gap G with respect to the flange 20 of the fixed part 12. Therefore, the bearing 28 allows the movable part 14 to rotate freely around the longitudinal axis XX on the sleeve 26, which is locked to rotate relative to the fixed part 12. As described above, the presence of the peripheral gap G ensures a reduction in friction during the rotation of the movable part 14 relative to the fixed part 12.

[0036] The following describes, with non-limiting typical examples, further preferred and optional structural features of the tail assembly 10 manufactured according to the embodiments of the present invention described above.

[0037] In the illustrated embodiment, the fixing portion 12 comprises a main portion 32 configured to be fixed to the body 2 of the projectile 1, and a stem 34 extending rearward from the rear of the main portion 32. In particular, the main portion 32 and the stem 34 are manufactured integrally.

[0038] In the illustrated embodiment, the main portion 32 is substantially hollow and defines a cup-shaped form. In particular, the main portion 32 supports a flange 20 that projects radially outward. The main portion 32 and the stem 34 are arranged around the longitudinal axis XX.

[0039] In the illustrated embodiment, the sleeve 26 of the connecting component group 24 is slidably attached to the stem 34 of the fixing portion 12. In addition, the sleeve 26 is locked to rotate on the stem 34.

[0040] In the illustrated embodiment, the disc spring 19 is mounted around the stem 34, abutting the rear of the main portion 32 on one side and abutting the flared upper part of the sleeve 26 on the other side. In particular, the disc spring 19 is housed in an annular groove 35 formed around the stem 34 at the rear of the main portion 32.

[0041] In the illustrated embodiment, the movable part 14 comprises a substantially hollow jacket 36 bearing radial stabilizing fins 16 on its exterior. The movable part 14 further comprises annular bodies 38 and tubular bodies 40 stacked along the longitudinal axis XX and fixed radially within the jacket 36. Thus, the annular bodies 38 and tubular bodies 40 translate and rotate integrally with the jacket 36 and are constrained by the jacket 36.

[0042] In the illustrated embodiment, the stem 34 of the fixed portion 12 is coupled to the annular body 38 via a group of connecting components 24. In particular, the bearing 28 and the sleeve 26 are interposed radially between the annular body 38 and the stem 34.

[0043] In the illustrated embodiment, the sleeve 26 of the connecting component group 18 can slide integrally with the bearing 28 and annular body 38 of the movable part 14 on the stem 34 of the fixed part 12 in the longitudinal axis XX direction, against the action of the disc spring 19.

[0044] Referring to Figure 7, the fixed portion 12 further includes a stop element, such as a stop ring 42, and the connecting component group 24 and / or movable portion 14 are configured to move closer to the stop element when pushed apart by the elastic component group 18.

[0045] In particular, when the stop ring 42 is fitted around the stem 34 and pushed out by the disc spring 19 to separate it, it is intended that at least one of the sleeve 26 of the connecting component group 24, the bearing 28 of the connecting component group 24, and the annular body 38 of the movable part 14 will come into close proximity.

[0046] In the illustrated embodiment, the fixed portion 12 further includes a spacer disc 44 that abuts axially with the bearing 28 (e.g., inner annular structure 28a) and / or the sleeve 26 of the connecting component group 24, in particular the spacer disc 44 abutting axially with the portion of the connecting component group 24 whose rotation with respect to the fixed portion 12 is locked. The fixed portion 12 also includes a guide elastic member 46 that abuts the stop ring 42 on one side and abuts the spacer ring 44 on the other side, pushing it in the longitudinal axis XX direction. In this way, in the separated state, the spacer disc 44 maintains an axial distance between the stop ring 42 and both the connecting component group 24 (especially the outer annular structure 28b) and the movable portion 12 (especially the annular body 38). This allows the movable portion 14 to rotate on the fixed portion 12 while avoiding unwanted friction, particularly between the annular body 38 and the stop ring 42.

[0047] In the illustrated embodiment, the sleeve 26 and the annular body 38 hold bearings 28 that are stacked axially or filled along the longitudinal axis XX, by shoulder portions (unnumbered) at the ends that press and hold all components together.

[0048] Referring to Figure 8, the distal end of the fixed part 12 and the connection with the movable part 14 are shown. In the illustrated embodiment, the group of connecting components 24 includes an additional bearing 48. In particular, this additional bearing 48 is fixed to the fixed part 12 on one side and to the movable part 14 on the other side by a fixing ring nut 52 which is screwed, for example, inside the tubular body 40 of the movable part 14. The fixing ring nut 52 supports the end of the stem 34 of the fixed part 12 and supports the additional bearing 48 so as to allow rotation and / or sliding of the movable part 14 relative to the tubular body 40.

Claims

1. A fixing part (12) is connected to the rear of the main body (2) of the projectile (1) and defines the longitudinal axis (X-X), A movable part (14) is provided with multiple stabilizing fins (16), attached to the rear of the fixed part (12), and is freely rotatable about the longitudinal axis (X-X). A tail assembly (10) for a guided projectile (1) comprising, The movable part (14) is The fixed part (12) and the movable part (14) are in contact with each other in the axial direction, The fixed portion (12) and the movable portion (14) are separated in the axial direction, and a peripheral gap (G) is defined between them in a separated state. Between the fixed part (12), it is movable in the axial direction, The system further includes a group of elastic components (18) that attempt to hold the movable part (12) in the separated state. A tail assembly characterized by the following.

2. The tail assembly according to claim 1, wherein the fixed portion (12) comprises a flange (20) located radially outward of the longitudinal axis (X-X), and the movable portion (14) comprises a shoulder end (22) configured to abut the flange (20) in the axial direction when in contact and to move away from the flange (20) in the axial direction when separated.

3. The tail assembly according to claim 1 or 2, comprising a group of connecting parts (24) that connects the fixed part (12) and the movable part (14), and which allows the movable part (14) to rotate freely around the longitudinal axis (X-X) relative to the fixed part (12) and to slide freely in the direction of the longitudinal axis (X-X) relative to the fixed part (12).

4. The tail assembly according to claim 3, wherein the group of connecting parts (24) moves integrally with the movable part (14) on the fixed part (12) in the direction of the longitudinal axis (X-X).

5. The tail assembly according to claim 4, wherein the group of elastic components (18) is interposed axially between the fixed portion (12) and at least one of the group of connecting components (24) and the movable portion (14).

6. The tail assembly according to any one of claims 3 to 5, wherein the group of connecting parts (24) is slidably mounted on the fixing part (12) along the longitudinal axis (X-X) and includes a sleeve (26) whose rotation relative to the fixing part (12) about the longitudinal axis (X-X) is locked.

7. The tail assembly according to claim 6, wherein the fixing portion (12) comprises a main portion (32) and a stem (34) extending rearward from the rear of the main portion (32), the sleeve (26) is slidably mounted thereon and rotation about the longitudinal axis (X-X) is locked.

8. The tail assembly according to claim 6 or 7, wherein the group of connecting components (24) comprises at least one bearing (28) that rotatably connects the movable portion (14) and the sleeve (26) around the longitudinal axis (X-X).

9. The tail assembly according to any one of claims 3 to 8, wherein the fixed portion (12) includes a stop member (42), and at least one of the connecting component group (24) and the movable portion (14) is configured to move toward the stop member (42) when pressed toward the separated state by the elastic component group (18).

10. The tail assembly according to any one of claims 1 to 9, wherein the group of elastic components (18) comprises at least one disc spring (19).

11. A guided projectile comprising the tail assembly according to any one of claims 1 to 10.

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