Field of the invention

The invention relates to a marine propulsion as defined in the preamble of independent claim 1.

The invention relates generally to cylcloidal-marine propulsion systems such as to flappin foil propulsors for marine vessels or the like.

Publication EP 2 944 556 presents a cycloidal marine-propulsion system. One problem with such cycloidal marine-propulsion system is that due to the relatively complex construction, mounting of a cycloidal marine-propulsion system to a ship and servicing of a cycloidal marine- propulsion system that is mounted to a ship is not easy

Objective of the invention

The object of the invention is to provide a marine propulsion unit that is easy to mount to a ship and that is easier to service.

Short description of the invention

The marine propulsion of the invention is characterized by the definitions of independent claim 1.

Preferred embodiments of the marine propulsion are defined in the dependent claims.

List of figures

In the following the invention will described in more detail by referring to the figures, which

Figure 1 shows an embodiment of the marine propulsion unit,

Figure 2 shoes the marine propulsion unit shown in figure 1 in a state, where one blade unit is removed,

Figure 3 shows a blade unit of the marine propulsion unit shown in figure 1,

Figure 4 shows the blade unit shown in figure 3 from another angle,

Figure 5 shows the marine propulsion unit shown in figure 1 in partly cut view,

Figure 6 shows a detail of the blade unit shown in figure 3 in cut view,

Figure 7 shows another embodiment of the marine propulsion unit in cut view, and Figure 8 shoes the marine propulsion unit shown in figure 1 in cut view and in a state, where one blade unit is removed.

Detailed description of the invention

The figures show an embodiment of the marine propulsion unit.

The marine propulsion unit comprises a rotary casing 1 rotatable about a central axis A. The marine propulsion unit comprises blades 2 extending axially from the rotary casing 1 for rotation with the rotary casing 1 about the central axis A. Each blade 2 is preferably, but not necessarily, mounted for pivotal movement about blade axes B generally parallel to the central axis A as illustrated in figure 5.

A blade shaft portion 3 of each blade 2 is at least partly surrounded by a blade housing 4 and a blade portion 5 of each blade 2 is outside the blade housing 4.

The blade housing 4 is releasable attached to the rotary casing 1.

Each blade 2 is supported in the blade housing 4 by means of bearings 6a and 6b for said pivotal movement i.e. to make possible said pivotal movement.

In the marine propulsion unit, each blade 2 can together with a respective blade housing 4 be considered to form a blade unit (not marked with a reference numeral).

The marine propulsion unit provides for several advantages. The blade 2 that is supported in the blade housing 4 by means of the bearings 6a and 6b provides for a clear spare part package. The blade 2 that is supported in the blade housing 4 by means of the bearings 6a and 6b provides for a pre-assembled module that can be tested and be approved for example by classification societies prior mounting the blade 2 to the rotary casing 1 of the marine propulsion unit. Mounting of the blades 2 to the rotary casing 1 is easy: Because the blade shaft portion 3 of the blade 2 is already fitted into the bearings 6a and 6b for example at a factory, the blade shaft portion 3 of the blade 2 need not to be fitted into the bearings 6a and 6b simultaneously when mounting the blade 2 to the rotary casing 1 for example at a shipyard. This also makes servicing and replacing of individual blades easy.This is an advantage, because the blades 2 can be 2 to 3 meters long. The risk that the bearings 6a and 6b are damaged is consequently reduced.

The marine propulsion unit comprises preferably, but not necessarily, a retaining arrangement (not shown in the figures) for keeping the blade shaft portion 5 of each blade 2 in a respective blade housing. Said retaining arrangement can for example comprise at least one of a wedge connection, a shrink connection, a retaining screw and a retaining ring.

The blades 2 are preferably, but not necessarily, evenly distributed at the rotary casing 1 with respect to the central axis A.

The rotary casing 1 of the marine propulsion unit comprises preferably, but not necessarily, a lower surface 7 that is configured to be at least partly in direct contact with water. The lower surface 7 can be flat as shown in the figures.

If the rotary casing 1 comprises such lower surface 7, the rotary casing 1 comprises preferably, but not necessarily, mounting seats 8 configured to releasable receive the blade housing 4 of each blade 2 such that the mounting seats 8 extend from the lower surface 7 of the rotary casing 1 into the rotary casing 1 and form apertures in the rotary casing 1. Alternatively, at least one mounting seat 8 can extend from the lower surface 7 of the rotary casing 1 into the rotary casing 1 so that said at least one mounting seat 8 form a recess in the rotary casing 1.

If the rotary casing 1 comprises such mounting seats, the blade housing 4 has preferably, but not necessarily, an outer surface 9, which can be a circumferential outer surface, as in figure 6, and the mounting seat 8 has preferably, but not necessarily, an inner surface 10, which can be a circumferential inner surface, as in figure 6, such that the outer surface 9 of the blade housing 4 at least partly abuts the inner surface 10 of the mounting seat 8 so as to prevent lateral movement of the blade housing 4 in the mounting seat 8. The inner surface 10 together with the outer surface 9 also functions as steering surfaces when mounting the blade housing 4 together with the blade 2 at the rotary casing 1.

If the rotary casing 1 comprises such mounting seats, the blade housing 4 has preferably, but not necessarily, a first section (not marked with a reference numeral) where the cross-section form and the outer dimensions of the blade housing 4 corresponds to the cross-section form and inner dimensions of a second section (not marked with a reference numeral) of the mounting seat 8 so as to prevent lateral movement of the blade housing 4 in the mounting seat 8. The first section together with the second section also functions as steering surfaces when mounting the blade housing 4 together with the blade 2 at the rotary casing 1.

Such first section of the blade housing 4 is preferably, but not necessarily, formed by a circumferential outer surface of the blade housing 4 that has an outer diameter that essentially corresponds to the inner diameter of a second section of the mounting seat 8 in the form of a circumferential inner surface of the mounting seat 8 extending from a lower surface 7 of the rotary casing 1 so as to prevent lateral movement of the blade housing 4 in the mounting seat 8.

The marine propulsion unit comprises preferably, but not necessarily, a mounting body 11, configured to attach the marine propulsion unit to a marine vessel or the like such as to a ship, preferably to the hull 23 of a ship, wherein the rotary casing 1 is rotatable mounted at said mounting body 11 for said rotation about the central axis A. The marine propulsion unit comprises preferably, but not necessarily, a rotating means 21 configured to rotate the rotary casing 1 with respect to the mounting body 11. The rotating means can comprise one of an electric motor, as in the embodiment illustrated in figures 7 and 8, a hydraulic arrangement, and a mechanical arrangement or a combination thereof.

The bearings for supporting the blades in the blade housings 4 comprise preferably, but not necessarily, a first bearing 6a and a second bearing 6b. The first bearing 6a is provided inside the blade housing 4 at a first end (not marked with a reference numeral) of the blade shaft portion 3 of the blade 2 and the second bearing 6b is provided inside the blade housing 4 at the opposite second end (not marked with a reference numeral) of the blade shaft portion 3 of the blade 2. An advantage of this is that the first bearing 6a and the second bearing 6b will as far from each other as possible and this provides for a stable supporting of the blades 2 in the blade housings 4.

If the bearings for supporting the blades in the blade housings 4 comprise a first bearing 6a and a second bearing 6b as described, the first bearing 6a is preferably, but not necessarily, a cylindrical bearing or a roller bearing. One purpose of the first bearing 6a is to transmit radial forces from the blade 2 to the rotary casing 1 via the blade housing 4. If the bearings for supporting the blades in the blade housings 4 comprise a first bearing 6a and a second bearing 6b as described, a first seal arrangement 12 is preferably, but not necessarily, provided between the blade shaft portion 3 of the blade 2 and the blade housing 4 at the first bearing 6a on the side of the first bearing 6a that faces the second bearing 6b. One purpose of the first seal arrangement 12 is to prevent lubrication from leaking from the first bearing 6a.

If the bearings for supporting the blades in the blade housings 4 comprise a first bearing 6a and a second bearing 6b as described, the second bearing 6b is preferably, but not necessarily, a spherical roller bearing. The spherical roller bearing transmits axial and radial forces from the blade 2 to the rotary casing 1 via the blade housing 4.

If the bearings for supporting the blades 2 in the blade housings 4 comprise a first bearing 6a and a second bearing 6b as described, a second seal arrangement 13 is preferably, but not necessarily, between the blade shaft portion 3 of the blade 2 and the blade housing 4 at the second bearing 6b on the side of the second bearing 6b that faces the blade portion 5 of the blade 2. One purpose of the second seal arrangement 13 is to protect the second bearing against water that at least partly surrounds the blade portion 5 of the blade 2, when the marine propulsion unit is mounted at a marine vessel and when the marine vessel floats in water. Another purpose of the second seal arrangement 13 is to prevent lubrication from leaking from the second bearing 6a.

If the bearings for supporting the blades in the blade housings 4 comprise a first bearing 6a and a second bearing 6b as described, a third seal arrangement 24 is preferably, but not necessarily, between the blade shaft portion 3 of the blade 2 and the blade housing 4 at the second bearing 6b on the side of the second bearing 6b that faces the first bearing 6a. One purpose of the third seal arrangement 24 is to prevent lubrication from leaking from the second bearing 6a.

Each blade comprises preferably, but not necessarily, a pivoting means 14 functionally connected between the blade 2 and the blade housing 4. The pivoting means 14 is configured to pivot the blade 2 with respect to the blade housing 4 for performing said pivotal movement of the blade 2 about blade axes B, which may be generally parallel to the central axis A. Each pivoting means 14 can comprise one of an electric motor, a hydraulic arrangement, and a mechanical arrangement or a combination thereof. Each pivoting means 14 is preferably, but not necessarily, independently operable. The blade portion 5 of each blade 2 comprises preferably, but not necessarily, an elongated leading edge 15 and an elongated trailing edge 16, and by the marine propulsion unit comprises preferably, but not necessarily, a steering unit 22 configurable to control the pivoting means 14 so that the trailing edge 16 of the blade portion 5 of each blade 2 moves in an ordinary cycloid or curtate cycloid path when the marine propulsion unit moves linearly when propulsing a marine vessel to move the marine vessel linearly or along a curve when propulsing a marine vessel to move the marine vessel along a curve.

If each blade 2 comprises a pivoting means 14, as described, the blade housing 4 encapsulates preferably, but not necessarily, the pivoting means 14. An advantage of this is that the blade housing 4 protects the pivoting means 14 during assembly at the rotary casing 1. Another advantage is that the pivoting means 14 can be sealed in the blade housing 4 against water by means of the blade housing 4. Another advantage of this is that this provides for an assembly-ready unit comprising both the blade 2 and the pivoting means 14 for pivoting the blade 2 with respect to the rotary casing 1.

If each blade 2 of the marine propulsion unit comprise a first bearing 6a and a second bearing 6b as described, and if each blade of the marine propulsion unit comprise a pivoting means 14, as described, the pivoting means 14 is preferably, but not necessarily, functionally connected to the blade shaft portion 3 of the blade 2 between the first bearing 6a and the second bearing 6b, as shown in figure 6. In such case, each pivoting means 14 is preferably, but not necessarily, an electric motor (not marked with a reference numeral), wherein the electric motor surrounds the blade shaft portion 3 of the blade 2 in the blade housing 4. If each pivoting means 14 is an electric motor, the stator 17 of the electric motor is preferably, but not necessarily, attached to the blade housing 4, and the rotor 18 of the electric motor is preferably, but not necessarily, attached to the blade shaft portion 3 of the blade 2, as shown in figure 7.

Each blade housing 4 comprise preferably, but not necessarily, at least one bolt flange 19 at the blade housing 4, wherein the bolt flange 19 is configured to co-operate with fastening means 20, such as with a co-operating bolt flange, at the rotary casing 1 for releasable attaching the blade housing 4 to the rotary casing 1.

Each blade housing 4 can for example comprise, as shown in the figures, a bolt flange 19 at one end of the blade housing 4, wherein the bolt flange 19 is configured to co-operate with fastening means 20, such as with a co-operating bolt flange, at the rotary casing 1 for releasable attaching the blade housing 4 to the rotary casing 1.

It is apparent to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples, but they may vary within the scope of the claims.