EP2261113B1 - Propeller - Google Patents

Description

The invention relates to a propeller, in particular a built propeller for a boat drive, but is not limited thereto.

In ship propulsion systems, it has long been state of the art to form the propeller in one piece as a casting, typically made of bronze. Such a propeller typically consists of a hub, on the peripheral surface of which connect the propeller blades. The production is usually done by casting in sand molds and manual or machine post-processing. The production of the molds is particularly complicated because of the overlap of the wings.

Operation of the propeller may cause damage to the wings due to floating objects. For larger damage to the wing repair is often not possible or at least not economically feasible, so that the entire propeller must be replaced, which is complicated and expensive. To avoid this, so-called built-propeller are known in which the wings are releasably mounted on a support body, typically a propeller hub. Such built propellers also allow the propeller to be constructed from a variety of materials, such as a metal hub and wings constructed of composite material. Such wings are particularly advantageous for use in military submarines because they have better damping properties and thus a lower signature than metallic wings. Disadvantage of the built propeller, however, is that they are very expensive to manufacture and that often the connection between the propeller blade and propeller hub is problematic, as well as leads to design restrictions.

Out DE 42 11 202 A1 It is the state of the art to provide at the propeller hub dovetailed grooves on the outer circumference, which extend helically around the axis of rotation and in which propeller blades are inserted positively with their corresponding dovetailed feet. The production of such dovetail-shaped grooves extending helically over the circumference of the hub is extremely expensive expensive. Even a small deviation in the groove geometry, the pitch or the like leads to rejects of the respective component.

Out WO 87/04400 A1 is a propeller to the prior art, in which both the hub and the wings arranged thereon are integrally constructed of composite material, but this has the disadvantage that on the one hand, the production is complicated because of required shapes and on the other hand, only one damage Repair of the wing, but usually no replacement of the same is possible.

In that regard, the cheaper is the off WO 00/66429 A1 known propeller, in which the wings of composite material, that is formed of a composite material, but the wing base is formed like a flange, wherein in the flange a plurality of bores are provided, are guided by the screws with which the wings on the support body, ie attached to the hub of the propeller. In the propeller described there, all wings are the same design and individually mounted or disassembled so that they can be replaced individually in case of damage. However, the production of the wings is very expensive, especially as in the area between the flange-like foot and the actual wing, the cross-section is significantly reduced. This requires, on the one hand, a complicated structure of the component in several process steps, on the other hand, that the tensile forces absorbing materials must be bent by 90 °, which is unfavorable, since the force can not be optimal and therefore does not use the actual strength of the material can be.

Out DE 20 2008 010 810 U1 It belongs to the state of the art to attach a rotatably mounted on a hub propeller by means of an intermediate ring which is clamped over wedge-shaped elements non-positively and positively. Although the construction described there is fundamentally suitable for fastening a rigid propeller to a support body, such as a shaft, the introduction of force into the propeller blade, in particular if this consists of a composite material, is not favorable.

Against this background, the invention has for its object to provide a propeller, which avoids the aforementioned problems, but at least reduced, in which the propeller blades are interchangeable and in particular made of composite materials produced wings can be used.

This object is achieved according to the invention by the features specified in claim 1. Advantageous embodiments of the invention are specified in the subclaims, the following description and the drawing. The features specified in the subclaims and in the following description can be used not only in the combination provided there by way of example but also alone or in another combination, if this appears advantageous.

The propeller according to the invention has a central supporting body and at least two propeller blades fastened to the circumference thereof, the cross-section of which is designed to taper in the region of its base near the supporting body with increasing radial distance from the supporting body. Each wing is fixed by means of a wing form-fitting comprehensive wing shoe on the support body.

The propeller according to the invention is therefore a built-propeller, which consists of a central support body typically a hub, which can be fixed in a conventional manner on a shaft. However, the support body may also be formed by the shaft itself or in another suitable manner. The basic components of the propeller according to the invention, namely the central support body, wings and the wing shoes can in principle be formed from any suitable materials. However, the embodiment according to the invention is particularly advantageous if, in particular, the propeller blades are constructed of composite material, that is to say a composite material, such as, for example, carbon fiber reinforced plastic.

The basic idea of the solution according to the invention is to provide a propeller which has a central supporting body on which wings are arranged on the circumference, the wings being fastened by means of wing shoes detachably on the supporting body, so that they are individually exchangeable. In this case, the wings in the foot area, so in the supporting body near the area designed so that they are cross-section tapering with increasing radial distance relative to the longitudinal and rotational axis of the support body, ie cone-like, regardless of the other form of the propeller, which typically beyond Foot area extends to the full wing shape widening. The wing shoe is formed correspondingly reversed, surrounds the wing base circumferentially and thus secures this form-fitting in the radial direction, since the wing root due to its cone-like with the tapered end radially outwardly facing shape can not penetrate this comprehensive shoe. The shoe itself is suitably attached to the support body. This training is followed by a nearly ideal introduction of force from wing to support body or vice versa. The wing is laterally supported in its foot area, ie transverse to its longitudinal axis by the shoe. In the direction of its longitudinal axis, in particular radially outward, there is a force deflection, ie the longitudinal direction the forces occurring are converted due to the cone-like design of the blade root and the corresponding reverse training of the wing shoe in transverse forces, which generate pressure forces on the wing root and tensile forces in the shoe. With appropriate design of the components so that very high forces can be absorbed and also transmitted, unlike that of propellers according to the prior art, in particular WO 00/66429 A1 the case is.

According to an advantageous embodiment of the invention, the wing shoes of the propeller according to the invention are fastened by means of screws to the support body. Such screw connections are standardized and also allow transmission of high forces. For attaching and releasing such screw no special tools are required, so they do not require much effort.

According to the invention, a wing shoe is not integrally formed, but is divided in the circumferential direction, since then the wing shoe is formed independently of the wing shape in the area beyond the blade root and can be mounted after manufacture of the wing. Typically, a propeller blade expands from its wearer-proximate end to its free end to form a wing shape. If the shoe is formed split, this can be attached after completion of the propeller blade by the shoe parts are applied from two sides to the foot and attached to it. According to the invention, the pitch of the wing shoe is provided so that the wing is surrounded on the two flat sides about half and only on a narrow side of a foot part. Advantageously, the division of the wing shoe is provided approximately half.

According to an advantageous embodiment of the invention, the wing shoe is designed so that it surrounds the wing foot not only circumferentially, but also has a sole that with their one Side facing the support body and with the other to the support body facing end face of the blade foot points. In such an embodiment, the wing foot is completely covered by the wing shoe.

The components of the propeller according to the invention can basically consist of the same or of different materials. However, it is particularly advantageous if the supporting body is made of metal, for example bronze, and the propeller blades are made of a composite material, in particular carbon-fiber-reinforced plastic. The structure of the wings of composite material is particularly advantageous, first, because the complex three-dimensional shape of these wings of such a composite material is relatively easy to manufacture, on the other hand, because thereby the weight of the propeller can be significantly reduced and ultimately, because such made of composite material wings have much better damping properties than metal wings. This is particularly advantageous when using the propeller on a military submarine, since this will have a favorable effect on the signature of the boat.

The wing shoes can in principle be formed from any suitable material. Advantageously, the invention provides, however, to form them of metal, as a result, the power transmission from the wing to the shoe and the shoe on the support body can be done in almost ideal manner without having a particularly high production cost. A complex shaping in the region of the shoe is required with a suitable design of the propeller only in the area in which engages the wing foot there. Incidentally, the Flügelfuß can have simple geometric shapes that are favorable to process manufacturing. In this case, any tolerances in the area of the receptacle of the shoe, that is, where the wing foot engages, can be at least partially compensated for by suitable manufacturing methods, for example, by potting the remaining spaces with an adhesive resin.

According to an advantageous development of the invention, the propeller blade is provided with a metallic core at least in the foot region. This core preferably has a cross-section which is tapered with increasing radial distance from the support body. Such a metallic core supports the introduction of force between the foot of the wing and the wing shoe and prevents evasion of the surrounding composite layers.

In order to fix the core securely within the wing, according to one embodiment of the invention, at least one recess in the core, but preferably one or more openings provided, which are penetrated by the plastic of the surrounding composite or filler material. In this way, a positive connection between the metallic core and the composite material or filling in this area plastic is achieved, which incorporates the core inextricably in the wing. In order to further improve the connection between the blade root and wing shoe, which is basically provided according to the invention, and to avoid load peaks in the composite, it is expedient, according to an embodiment of the invention by possible manufacturing tolerances or otherwise formed clearances between wing shoe and Flügelfuß, so there where the wing foot sits in the receptacle of the wing shoe to fill with plastic. These are advantageously filled with adhesive resin, which additionally connects the components together materially.

The support body of the propeller according to the invention is advantageously not provided as usual with a round outer contour, but according to an embodiment of the invention with a polygonal cross section, preferably a regular polygonal cross section. Such polygonal outer contour is manufacturing technology easy to manufacture, especially in the field of wing shoes, which are then to be provided on its radially inward-facing side only with one or more flat surfaces.

It when the support body has a straight prismatic outer contour, since this simplifies both the production of the support body and the shoes is particularly advantageous. It is structurally particularly advantageous if a wing shoe not only extends over one but at least over two or even advantageously over three sides of the polygonal cross-section, as this can improve the mechanical strength of the structure can be achieved.

In this case, the wing shoes according to the invention are advantageously designed and arranged so that they completely cover the supporting body circumferentially and preferably form a cylindrical, frusto-conical or other desired basic contour. A basic contour in the sense of the invention is to be understood as meaning the contour that results when the blades and the part of the blade shoe enclosing this collar-like shape in the area of the blade root are neglected.

The achievement of a cylindrical or truncated cone-shaped base contour by the wing shoes has the advantage that the polygonal cross-sectional shape of the support body does not appear to the outside and flow and signature technology, the effect of a conventional hub is achieved.

In order to align the wing shoes in the axial direction of the support body, according to the invention can be provided on one side of the support body, advantageously on both sides, a frontal stop. Such an end stop can be formed by annular disks, which are connected to the support body or which are bolted together with the support body on the shaft.

Although the propeller invention is particularly advantageous for a ship propulsion, especially that of a submarine, applicable, but the structural design is not limited thereto. A correspondingly adapted structurally configured propeller can be used for example as a wind turbine of a wind turbine or as a fan.

Fig. 1

in stark vereinfachter perspektivischer Darstellung einen Propeller gemäß der Erfindung,

Fig. 2

einen Tragkörper mit einem daran befestigten Flügel sowie Flügelschuh in perspektivischer Darstellung,

Fig. 3

eine Draufsicht auf einen Flügelschuh, und

Fig. 4

einen Schnitt durch einen Teil des Tragkörpers, des Flügel- schuhs sowie des damit befestigten Flügels im Befesti- gungsbereich.

The invention is explained in more detail with reference to an embodiment shown in the drawing. Show it:

Fig. 1

in a greatly simplified perspective representation of a propeller according to the invention,

Fig. 2

a supporting body with an attached wing and wing shoe in perspective view,

Fig. 3

a plan view of a wing shoe, and

Fig. 4

a section through a part of the support body, the wing shoe and the wing mounted therewith in the mounting area.

The propeller shown in the figures has a support body 1, which is designed as a hub. The existing metal support body 1 has a central bore 2, as is common in propellers for watercraft. The outer contour of the support body 1 is not round, but angular. The support body 1 shown here has a seven-cornered cross section, so that there are seven flat sides 3, which are arranged parallel to the axis of rotation 4 of the support body 1.

On the support body 1 a total of seven propeller blades 5 are arranged distributed uniformly over the circumference. The wings 5 are shown only in the supporting body near area, they are arranged obliquely to the axis of rotation 4 and each have two flat sides 6 and 7 and two narrow sides or edges 8 and 9. The propeller blades 5 are fastened via wing shoes 10, which comprise the propeller blades 5 in the area of the blade root 11 in a form-fitting and complete manner. The wing shoes 10 have a plurality of holes 12 which are aligned with corresponding threaded holes in the flat sides 3 of the support body 1 and which are penetrated by cap screws 13, with which the wing shoes 10 are detachably attached to the support body 1.

Support body 1 and wing shoes 10 are formed of metal, whereas the wings 5 are constructed of composite material, here of carbon fiber reinforced plastic.

The wing base 11 of each propeller blade 5 has a cross-section decreasing radially outward from its supporting body-proximal end, whereas the female wing shoe 10 is inversely proportioned in the region of its receptacle for the wing base 11, ie the receptacle has a cross section increasing towards the supporting body 1. In any case, wing foot 11 and wing shoe 10 are formed so that the wing shoe 10 engages around the wing leg 11 positively and holds, as best of FIG. 4 is apparent. In this case, the wing shoe 10 surrounds the wing foot 11 not only circumferentially, but also on the tragkörperseitigem end, ie the Flügelfuß 11 has no direct contact with the support body 1, but is exclusively connected via the wing shoe 10 with this.

Within the wing 5, a metallic core 14 is provided in the foot region 11 and radially beyond reaching, the cross section of Tragkörpernahen end decreases radially outward and thus represents a kind of wedge in the connection between the wing base 11 and wing shoe 10, which ensures that with increasing load of the compound sufficient internal resistance is formed, so that the forces applied by the composite material of the wing forces can be transferred into the shoe 10. The metallic core 14 has an in FIG. 4 visible longitudinal aperture 20, which is interspersed with the surrounding plastic 15 and thus the core 14 positively holds within the wing foot 11.

The wing shoes 10 are, as also shown in FIG FIG. 1 shows, a plurality of surfaces 3 of the support body 1 formed across. They have on the inside three flat surfaces which extend over a total of three flat surfaces 3 of the support body 1 and are formed teilkonisch on the outside, so that when all shoes are mounted, forms a substantially frusto-conical outer surface like a conventional hub.

Since a propeller blade 5 of its foot portion 11 radially outwardly, typically in cross-section widening not insignificant, the wing shoe 10 is even if he does not engage the wing leg 11 directed to the support body 1 end face, split to him after completion of the wing 5 to mount. The division takes place, as based on the Figures 2 and 3 clearly visible, so that each partial shoe 16, 17 two flat sides 6, 7 in half and a narrow side or edge 8 or 9 surrounds. The division is approximately half, so that each partial shoe 16, 17 includes the wing foot 11 by about 180 °.

The production of the above-described propeller is such that the support body 1 is made of a casting or solid material machined, as well as the wing shoes 10. For the basis of FIG. 1 Propellers shown are therefore a total of seven identical partial shoes 16 and seven identical partial shoes 17 manufacture. The propeller blades 5 are manufactured, for example, so that each wing is formed from two wing halves, which are each manufactured in a corresponding shape, with a sufficiently thick CFK layer on the outside. These layers are then connected to each other with the inclusion of the metallic core 14 and backfilling of the remaining space with plastic 15 to a wing 5. The wing thus formed is now surrounded in a corresponding device with the part shoes 16 and 17. About holes 18 in the sole 19 of the shoe 10 adhesive resin is then introduced, which fills any space between wing foot 11 and the inclusion in the wing shoe 10 and in addition to the positive connection between the wing base 11 and wing shoe 10 additionally creates a cohesive connection, these components firmly and securely connects with each other. After curing of the adhesive resin of the wing 5 is then secured by means of cap screws 13 on the support body 1, wherein for alignment in the axial direction 4 corresponding stops in the form of rings can be provided on the front and back of the support body 1, which ensure that the wing shoes 10th are aligned the same in the axial direction. When all the propeller blades 5 are screwed with their wing shoes 10 with the support body 1, there is a closed frustoconical propeller main body, as in FIG. 1 is shown.

In the case of the illustrated in the embodiment of two parts 16 and 17 wing shoes 10, the receptacle for the Flügelfuß 11 is formed by a recess in base material on the one hand and a collar-shaped Anformung on the other. It is understood that it may be possible to dispense with the collar-shaped molding, if the base material is chosen to be correspondingly stronger. Here is a compromise of fluidic requirements on the one hand and strength requirements on the other hand to find.

It is understood that the above-described production of the propeller blade with shoe is to be understood only as an example, since in practice other manufacturing steps to achieve a wing and a suitable intimate connection between the wing base 11 and wing shoe 10 can be used.

LIST OF REFERENCE NUMBERS

1

- Support body

2

- Drilling

3

- flat side

4

- rotation axis / longitudinal axis

5

- Propeller blades

6

- Flat side of the wing

7

- Flat side of the wing

8th

- narrow side of the wing or edge

9

- narrow side of the wing or edge

10

- Wing shoe

11

- Wing foot

12

- Drilling in 10

13

- head screws

14

- metallic core in 5

15

- Plastic filling in 5

16

- Part shoe

17

- Part shoe

18

- holes in 19

19

- sole

20

Breakthrough in 14

Claims (17)

1. A propeller with a central carrier body (1) and with at least two propeller blades (5) which are fastened thereon on the peripheral side and whose cross section, in their root region (11) close to the carrier body, is designed in a tapering manner with an increasing radial distance to the carrier body (1), and with which each blade (5) is fastened on the carrier body (5) by way of a blade shoe (10) which encompasses the blade (5) with a positive fit, characterised in that a blade shoe (10) is designed in a divided manner and the shoe parts (16, 17) in each case engage around the blade (5) at both flat sides (6, 7), but only at one narrow side (8, 9).
2. A propeller according to claim 1, characterised in that the blade shoes (10) are fastened on the carrier body (5) by way of screws (13).
3. A propeller according to claim 1 or 2, characterised in that a blade shoe (10) is designed in a manner divided into two shoe parts (16, 17) engaging around a blade root (11) by roughly half.
4. A propeller according to one of the preceding claims, characterised in that a blade shoe (10) with its sole (19) encompasses a blade root (11) also at the face side facing the carrier body (5).
5. A propeller according to one of the preceding claims, characterised in that the carrier body (1) consists of metal and the propeller blades (5) are constructed of a composite material, in particular of a carbon-fibre reinforced plastic.
6. A propeller according to one of the preceding claims, characterised in that the blade shoes (10) are formed from metal.
7. A propeller according to one of the preceding claims, characterised in that the propeller blades (5) at least in the root region (11) have a preferably metallic core (14), whose cross section is designed tapering with an increasing radial distance to the carrier body (1).
8. A propeller according to one of the preceding claims, characterised in that the core (14) comprises at least one recess, preferably opening (20), through and in which plastic (15) of the surrounding material is filled.
9. A propeller according to one of the preceding claims, characterised in that free spaces between the blade shoe (10) and the blade root (11) are filled with plastic, in particular bonding resin.
10. A propeller according to one of the preceding claims, characterised in that the blade root (11) and the blade shoe (10) are bonded to one another.
11. A propeller according to one of the preceding claims, characterised in that the carrier body (1) comprises a preferably regular polygonal cross section.
12. A propeller according to one of the preceding claims, characterised in that the carrier body (1) has a straight prismatic outer contour.
13. A propeller according to one of the preceding claims, characterised in that the blade shoes (10) are designed and arranged such that they completely cover the carrier body (1) on the peripheral side and preferably form a cylindrical or truncated-cone-shaped basic contour.
14. A propeller according to one of the preceding claims, characterised in that a blade shoe (10) extends over at least two adjacent sides of the polygon cross section.
15. A propeller according to one of the preceding claims, characterised in that the blade shoes (10) in the axis direction (4) of the carrier body (1) bear at least at one side on a face-side abutment.
16. A propeller according to one of the preceding claims, characterised in that the carrier body (1) is designed as a hub.
17. A vessel, in particular a submarine with a propeller according to one of the preceding claims.

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