EP0579533A1 - Rudder blades for medium and large sized ships - Google Patents

Abstract

The invention relates to rudders produced almost exclusively from composite materials. In a rudder according to the invention, comprising a fin (1) orientable around a wick, these two elements being made of composites, the lower part of the wick has a polygonal section to be engaged in a box (4) of corresponding section forming part of the structure of the fin 1, so that they are mutually locked in rotation. The box (4) is assembled to the rest of the structure of the fin (1) by joining over the whole of at least one of its lateral faces. In a preferred embodiment, the fin (1) has a structure formed by gluing a plurality of boxes (13 to 18 and 4). <IMAGE>

Description

The present invention relates to rudders in general: stabilization rudders for surface ships, steering rudders, and diving rudders for submarines. In all cases, these are fins which can be oriented from the ship by means of a drill bit.

Currently, for ships above a certain tonnage, the rudders are made entirely of metal. They comprise a mechanically welded framework on which the hydrodynamic envelope is mounted, obtained by welding sheets previously formed in the hot state. The interface with the drill bit is a massive part produced by molding, the surfaces of which are machined. The steel drill bit is forged and then machined.

This solution is expensive and implements painful manufacturing processes, in particular hot forming. On the other hand, it results in very heavy products, in an area where weight gain is always interesting.

An object of the invention is to overcome these drawbacks, namely to reduce the mass of such rudders substantially and to make their manufacture less laborable by eliminating hot forming, by the use of composite materials.

Another important object of the invention is the almost exclusive use of composite materials for the production of these rudders, both at the level of the fin and of the wick and of the connection interface between the two, in particular to avoid metal-composite structural associations which are never without drawbacks.

In this context, a major problem was that of the connection between the drill bit and the fin, which is the seat of significant efforts since it is through it that the torques are transmitted, and which, for practical reasons, must be removable.

According to the invention, the solution provided consists in providing in the structure of the fin a box for receiving the lower part of the wick, their sections being polygonal, for example hexagonal, to ensure between them a rotation lock.

Said receiving box of the lower part of the wick is joined by all of at least one of its lateral faces to the rest of the structure of the fin. It is advantageously made of glass-resin composite.

In a preferred embodiment, the structure of the fin comprises an assembly of separate boxes of which said box receives the lower part of the wick.

The latter also requires a particular manufacturing technique, due to the significant torsional and bending forces to which it is subjected.

According to an important characteristic of the invention, it is carried out by association of the filament winding technique and the draping technique. The first makes it possible to give an oblique orientation of the reinforcing fibers - for example at + 45 ° and at -45 ° - relative to the longitudinal axis of the wick, and the second an orientation at 0 °. They are preferably carbon fibers.

In addition to the drill bit and the fin, the rudders have a spur, which is subjected to significant shear forces. Therefore, it is advantageously produced in the general form of a full cylinder made up of rods of pultruded glass-resin composite, compacted and bonded with resin.

• la Fig. 1 illustre un safran de direction du type dit à compensation monté sur un navire et présentant une liaison mèche-aileron, vue en coupe axiale, conforme à l'invention,
• la Fig. 2 est une vue agrandie, également en coupe axiale, de la liaison mèche-aileron du safran de la Fig. 1,
• la Fig. 3 est une vue en coupe selon la ligne III-III de la Fig. 2,
• la Fig. 4 est une vue agrandie en coupe axiale illustrant la liaison aiguillot-aileron du safran de la Fig. 1,
• la Fig. 5 est une vue en coupe selon la ligne V-V de la Fig. 4,
• la Fig. 6 est une vue en coupe verticale d'une forme de réalisation préférée de l'aileron du safran de la Fig. 1, et
• les Fig. 7 et 8 sont des vues agrandies en coupe, respectivement selon la ligne VII-VII et la ligne VIII-VIII de la Fig. 6.

Other characteristics and advantages of the invention will emerge from the explanations which follow and from the appended drawings, in which:

• Fig. 1 illustrates a rudder of the type known as compensation mounted on a ship and having a wick-fin link, seen in axial section, in accordance with the invention,
• Fig. 2 is an enlarged view, also in axial section, of the wick-fin link of the rudder of FIG. 1,
• Fig. 3 is a sectional view along line III-III of FIG. 2,
• Fig. 4 is an enlarged view in axial section illustrating the needle-fin connection of the rudder of FIG. 1,
• Fig. 5 is a sectional view along the line VV of FIG. 4,
• Fig. 6 is a vertical sectional view of a preferred embodiment of the rudder fin of FIG. 1, and
• Figs. 7 and 8 are enlarged sectional views, respectively along line VII-VII and line VIII-VIII of FIG. 6.

In Fig. 1, a steering rudder is shown in place on a ship of which only the bottom F and the butt C appear very schematically. It is a rudder of the type with compensation for the fact that at the bottom of the fin 1 part of it is on the other side of the axis of rotation XX relative to its main part. Fin 1 is suspended and articulated by through a wick 2 and a spur 3, both focused on XX.

According to the invention, almost all of the rudder, namely fin 1, wick 2 and spur 3, is made of composite materials. The only metal parts are two connecting inserts allowing conventional fixing methods and rings attached to the drill bit 2 at the P bearings.

In the known version of these rudders, entirely metallic, the wick is connected to the fin via a hub. It is generally engaged in the hub by conical fitting, the latter being welded to the frame of the fin. This connection system is simple and does not lead to any particular technical difficulties.

On the other hand, in the context of the invention, it would not have been judicious to transpose this system because of its non-adaptation to the characteristics of composite materials, and also because it would have induced relatively complex shapes of parts. .

The difficulty, for the inventors, was therefore to completely free themselves from the known technique to find an optimal solution, having regard to the almost exclusive use of composite materials.

According to the invention, the solution found consists of a tubular box 4 secured to the rest of the structure of the fin 1, of polygonal section, and preferably hexagonal as in the drawing, FIG. 3, admitting the lower part of the drill bit 2 of corresponding section. Locking in rotation is therefore ensured by the shape of the sections, and perfect by adding a setting resin in 5. For locking in translation, a metal ring 6, Figs. 2 and 3, is glued to the inside of the box 4, and an end piece 7 at the lower end of the wick 2, the end piece 7 and the ring 6 being secured to each other by keying.

The box 4 is advantageously made of glass-resin composite. As can be seen in Fig. 1, it extends clearly beyond the lower end of the drill bit 2, in fact up to the appendix Ca of the butt C in which the pivot pin 3 revolves. To allow the latter to be fitted during assembly rudder on the ship, the box 4 has a side hatch 8, and is open at its lower end, therefore having in fact a tubular shape.

The fact of extending the box 4 as much as possible has the advantage of having an area which is all the more important for its junction with the rest of the structure of the fin 1. In a preferred embodiment, this junction is made by gluing over the entire extent of a side face of the box 4. In a rudder of different shape such as a stabilization rudder in particular, where the box 4 occupies an intermediate position in the structure of the fin, there are of course two opposite lateral faces of the box 4 for the junction with the rest of said structure.

The wick 2 has also been the subject of special research, as to the problem of its resistance as a function of the torques and the very large bending forces to which it is subjected, and as to the best way to achieve it.

This resulted in a hollow wick 2, obtained by combining two techniques for using composite materials: filament winding and draping, and using a mandrel whose section changes gradually, in an intermediate zone, from the circular shape to the polygonal shape. In terms of reinforcements, the choice was made on carbon fibers, which are cheaper than more efficient aramid or boron fibers, oriented obliquely, for example at + and -45 ° by filament winding, and longitudinally at 0 °. by draping, the winding and draping operations are preferably alternated. In order to mitigate the risk of galvanic corrosion, it was planned to make the outer folds with glass fibers.

As already mentioned, the drill bit 2 is finalized by bonding the end piece 7 in its lower end and rings 9 for rotation in the bearings P.

The spur 3 is essentially, but highly stressed in shear, which has led to design it in the form of a solid cylinder, with fibers oriented longitudinally. A simple and economical way to manufacture it consists of compacting rods or rods in glass-pultruded resin composite, in a resin with high mechanical characteristics. An envelope is then produced by draping to obtain its final shape.

The spur 3 engages in a cylindrical cavity 10 formed in the body of the fin 1, FIG. 4. As for wick 2, a metal connection is provided to fix it to the fin, that is to say an end piece 11 glued to its lower end, keyed into a ring 12 inserted in the body of the fin 1. This connection is visible in Figs. 4, 5. It will be noted that the ring 12 has been given a square external shape in order to obtain good immobilization in the body of the fin 1 which may be syntactic foam in this area.

Another important aspect of the invention resides in the design of the structure of the fin 1 which must have a satisfactory resistance in compression and in bending. The fin 1 may essentially consist of an envelope made of sandwich type materials with a honeycomb core, or else of a machined honeycomb block covered with a composite envelope. glass-resin, or two half-shells that have just been bonded to a network of monolithic stiffeners, the filling material being syntactic foam, or even an assembly of glass-resin composite parts with also syntactic foam filling.

However, in a preferred embodiment, illustrated in Figs. 6 to 8, the fin 1 comprises, in addition to the box 4 serving for the connection with the wick 2, a plurality of boxes glued together, and the whole of which has a shape close to its final shape. These boxes are arranged in such a way that the glue interfaces are stressed in shear. These are advantageously machined foam blocks covered with a glass-resin composite envelope. The foam used is for example a high density foam based on polyvinyl chloride. When the boxes are assembled, a structure is obtained in which the adjacent glued walls form as many stiffeners. In Fig. 6, the rudder comprises two superimposed upper boxes 13 and 14, glued by one of their sides to the assembly of a side face of the box 4 receiving the wick 2, FIG. 7, an intermediate box 15 glued under the box 14 and three juxtaposed lower boxes 16 to 18, two of which, 16 and 17, are glued by their upper face below the intermediate box 15. Of course, the number and the arrangement of the boxes are determined based on the shape of the fin and how it is stressed.

To obtain the final shape of the fin, the assembled boxes are then introduced into a mold where they are coated with a foam identified in 19, advantageously syntactic foam, covered with an envelope 20 of glass-resin composite.

This design of the fin 1 makes it possible to obtain excellent continuity in the structure and has the other advantage of using only simple and well mastered manufacturing techniques.

The invention which has just been described is directly applicable to the production of stabilizing rudders. Regarding rudders for submarines, it requires a simple adaptation when choosing the materials for the fin - more especially the foams - according to their characteristics of resistance to pressure. In particular in this application to submarines, the invention is of great interest in that it provides a very substantial weight gain, since it is greater than 70%, compared to current metal versions. The gain is also real from the point of view of manufacturing cost, and especially from the point of view of maintenance, due to the virtual disappearance of metal parts, and consequently the risks of corrosion.

Claims (18)

1) rudder comprising a fin (1) orientable around a wick (2), characterized in that the fin (1) and the wick (2) are made of composite materials, and in that the lower part of the wick has a polygonal section to be engaged in a box (4) of corresponding section forming part of the structure of the fin (1) so that they are locked mutually in rotation, the box (4) being assembled to the rest of the structure of the fin (1) by joining over the whole of at least one of its lateral faces. 2) Saffron according to claim 1, characterized in that the lower part of the wick (2) and the box (4) have a hexagonal section. 3) Saffron according to claim 1 or 2, characterized in that the box (4) is made of glass-resin composite. 4) Saffron according to one of claims 1 to 3, characterized in that the wick (2) is obtained by combining the techniques of filament winding and draping. 5) Saffron according to claim 4, characterized in that the wick (2) comprises fibers oriented at + and -45 ° and fibers oriented at 0 ° relative to its longitudinal axis. 6) Saffron according to one of claims 1 to 5, characterized in that the wick (2) comprises carbon fibers. 7) Saffron according to claim 6, characterized in that the reinforcements of the outer plies of the wick (2) are glass fibers. 8) Saffron of the type further comprising a spur (3), characterized in that the spur (3) is also made of composite material, consisting of pultruded glass-resin composite rods, compacted and bonded with resin. 9) Saffron according to one of claims 1 to 8, characterized in that the box (4) intended to receive the lower end of the wick (2) is part of a multi-box structure. 10) rudder according to claim 9, characterized in that said boxes are joined to each other by gluing their adjacent walls, the arrangement of the boxes being such that the main forces on the adhesive interfaces are shear forces. 11) rudder according to claim 10, being a steering rudder, characterized in that it comprises at least two superimposed boxes (13, 14) glued together, and each glued to the box (4) connecting with the wick (2) by one of their lateral faces. 12) Saffron according to claim 11, characterized in that it further comprises boxes (16 to 18) juxtaposed, glued together, and glued to the upper boxes by at least the upper face of one of them. 13) Saffron according to claim 12, characterized in that it comprises three upper boxes (13 to 15) superimposed and three lower boxes (16 to 18) juxtaposed. 14) Saffron according to one of claims 9 to 12, characterized in that said multi-box structure is coated with syntactic foam (19). 15) Saffron according to claim 14, characterized in that it further comprises an outer envelope (20) of glass-resin composite. 16) Saffron according to one of claims 9 to 15, characterized in that the bodies of the boxes other than the box (4) are blocks of foam. 17) Saffron according to claim 16, characterized in that the foam constituting the body of the boxes is high density polyvinyl chloride foam. 18) Saffron according to claim 16 or 17, characterized in that said blocks are coated with a glass-resin composite envelope.

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