WO2018198063A1

WO2018198063A1 - Inboard propulsion unit for boats and boat provided with said propulsion unit

Info

Publication number: WO2018198063A1
Application number: PCT/IB2018/052898
Authority: WO
Inventors: Claudio BOSSI
Original assignee: B4S Sa
Priority date: 2017-04-28
Filing date: 2018-04-26
Publication date: 2018-11-01
Also published as: EP3615417A1; IT201700046071A1

Abstract

In a boat (1), an inboard propulsion unit (2), wherein the propulsion unit (2) comprises two electric propulsion devices (3), each one provided at least with: - a propeller assembly (6), which can be moved between an active condition, in which it protrudes downward from the hull (S), and an inactive condition, in which it is contained inside the hull (S); - an electric motor for driving the propeller assembly (6); wherein the propeller assemblies (6) of the electric propulsion devices (3), in the active condition, are extended at an angle with respect to a central plane of symmetry (Y) of the hull (S) of the boat (1).

Description

INBOARD PROPULSION UNIT FOR BOATS AND BOAT PROVIDED WITH SAID PROPULSION UNIT

The present invention relates to an inboard propulsion unit for boats, preferably but not exclusively for sailing boats, and a boat, preferably but not exclusively a sailing boat, which is provided with such propulsion unit.

As is known boats, for example sailing boats, are usually provided with a propulsion unit which is provided with an engine which is useful, for example, for mooring maneuvers in port, or when there is no wind.

Such inboard engines comprise a propeller assembly that protrudes from the bottom of the hull and remains in the water; the heat engine is accommodated in the hull and is connected to the propeller assembly with a transmission shaft which passes through the hull.

Such solutions are not devoid of intrinsic drawbacks, among which is the fact that in a boat (and especially in a sailing boat) hydrodynamic drag must ideally be as reduced as possible.

Furthermore, especially in boats that spend a long time in water, in areas with medium to high temperatures, the propeller assembly becomes covered with marine vegetation fairly quickly, further increasing hydrodynamic drag and making frequent cleaning necessary.

The aim of the present invention consists in providing an inboard propulsion unit for boats, and a boat provided with such propulsion unit, that solves the above technical problem, eliminates the drawbacks, and overcomes the limitations of the known art, by making it possible to have an inboard propulsion unit available which can profitably be used even when the boat is listing.

Within this aim, an object of the present invention is to provide such a propulsion unit and a boat that comprises such unit, in which the space occupation can be contained.

Another object of the invention consists in providing such a propulsion unit and a boat that comprises such unit, which can be easily used.

Another object of the invention consists in providing such a propulsion unit and a boat that comprises such unit, which are less subject to operations of maintenance and/or cleaning.

Another object of the invention consists in providing such a propulsion unit and a boat that comprises such unit, which present reduced hydrodynamic drag when the motor is not used.

This aim and these and other objects which will become better apparent hereinafter are achieved by a propulsion unit according to claim 1.

Further characteristics and advantages of the invention will become better apparent from the description of some preferred, but not exclusive, embodiments of a propulsion unit and a boat, which are illustrated by way of non-limiting example with the aid of the accompanying drawings wherein:

Figure 1 is a rear view of an embodiment of a propulsion unit applied to a boat in a first condition, according to the invention;

Figures 2 and 3 are side views of the propulsion unit of Figure 1, in two different conditions;

Figures 4 and 5 are perspective views of part of the propulsion unit of Figure 1 in two different conditions, corresponding to the conditions in Figures 2 and 3;

Figure 6 is an exploded perspective view of part of the propulsion unit of the previous figures;

Figure 7 is a perspective view of a second embodiment of a propulsion unit applied to a boat, in a first active condition;

Figure 8 is a perspective view of the propulsion unit of Figure 7 in an initial inactive condition;

Figure 9 is a perspective view of the propulsion unit of Figures 7 and 8 in a final inactive condition;

Figure 10 is a partially cross-sectional front elevation view of the propulsion unit of Figures 7-9 in a final inactive condition.

With reference to the figures, part of a boat 1 is shown, preferably a sailing boat, which is provided with an inboard propulsion unit 2 according to the invention.

The propulsion unit 2 comprises two electric propulsion devices 3, each one provided at least with a propeller assembly 6, which can be moved between an active condition, in which it protrudes downward from the hull S (Figures 1, 2 and 4), and an inactive condition, in which it is contained inside the hull S (Figures 3, 5).

This makes it possible to have the propeller assembly 6 exit only when necessary, and instead keeping it accommodated in the hull (i.e. not immersed) when it is not necessary; this makes it possible to reduce not only the drag of the boat when the motor is not required (for example because sails are being used), but also to reduce any need for maintenance, because the propeller assembly 6 at least is not constantly immersed.

Each propulsion device 3 also comprises an electric motor for driving the propeller assembly 6.

In an embodiment, the electric motor is accommodated in a housing 4, which is part of the electric propulsion device 3 and is mounted internally in the hull S; we will return to the details of the housing 4 shortly.

Preferably the motor is accommodated in the housing 4 in a volume that is separate from the internal chamber thereof that accommodates the propeller assembly 6 when the latter is in the inactive condition.

In some preferred solutions, the volume that accommodates the electric motor and its components is separate and watertight. In this manner the electric motor and its circuits and components remain advantageously isolated from the marine environment and not exposed to the action of sea water, thus extending its operating life and reducing the need for maintenance. In these embodiments, between the motor and the propeller assembly 6 there are kinematic chains for transmitting motion, which are conventional and are not described in detail here.

In other embodiments the electric motor is instead incorporated with the propeller assembly and accommodated in a watertight housing adjacent to the propeller assembly 6.

Note that the electric motor, with respect to a normal heat engine, makes it possible to reduce noise to levels that are substantially imperceptible by the occupants and to also reduce pollution; the electric motor can be powered with conventional means, for example accumulator batteries, solar panels, generators and the like.

According to the invention and as can clearly be seen in Figure 1, the propeller assemblies 6 of the electric propulsion devices 3, in the active condition, are extended at an angle with respect to a longitudinal central plane of symmetry Y of the hull S of the boat 1.

Preferably, the propeller assemblies 6 extend diverging downward, when the boat is in the condition of operation.

The central plane of symmetry Y is the plane that longitudinally divides the boat and if the boat has a keel, the plane Y passes through it.

In this manner several advantages are obtained: firstly, even if there is a central keel blade, the unit 2 will not interfere with it; furthermore, when the boat is listing (inclined) to one side, for example owing to an intense wind, then at least one of the two propeller assemblies 6 will always be in a condition of complete immersion; in this case the other propeller assembly could be brought if necessary to the inactive position and thus further protected from the elements.

According to an advantageous characteristic, each electric propulsion device 3 comprises a respective supporting shaft 8 which supports, at one of its ends, the propeller assembly 6.

The latter comprises a propeller 6A which is coupled to the supporting shaft 8, at a free end thereof.

The supporting shaft 8 can translate along a direction of motion M in order to allow the transition of the respective propeller assembly 6 between the active condition and the inactive condition, and vice versa; the direction of motion M lies on a substantially vertical plane, with the boat in the configuration for operation, and is inclined with respect to the central plane of symmetry Y of the hull S of the boat 1.

The propeller assembly 6, in the preferred and illustrated form, in addition to the propeller 6A also comprises a substantially cylindrical section of duct 6B, in the form of a tube, which improves the propulsive work overall and at the same time protects the propeller 6A from any impacts, for example in mooring maneuvers or with very shallow sea floors.

In the preferred and illustrated form, the propeller assembly 6 also comprises two bulkheads 12A and 12B:

- a first bulkhead 12A provided on the side of the propeller 6A that lies opposite the one that is coupled to the supporting shaft 8, and

- a second bulkhead 12B arranged substantially transversely on the supporting shaft 8 and parallel to the first bulkhead 12 A, located on the side of the propeller 6A that lies opposite the one supporting the first bulkhead 12 A, in such a way that the propeller 6 A and optionally the duct 6B that encompasses it are interposed between the two bulkheads 12A and 12B.

With specific reference to Figures 4 and 5, it is to be noted that on the hull S of the boat there is a perforated passage 13 for each propulsion device 3. Such passage 13 allows the transition at least of the propeller assembly 6 between the inactive condition and the active condition.

In particular, note that when a propeller assembly 6 is in the inactive condition (Figure 4), the first bulkhead 12A is aligned with the hull of the boat, to close the respective perforated passage 13, so as to restore the continuity of the hull S.

Preferably the bulkheads 12A and 12B are adapted to generate a watertight closure of the housing 4, for example by being provided with sealing gaskets that cooperate between the bulkheads 12A, 12B and a lip 12C of the housing 4.

Conversely, when a propeller assembly 6 is in the active condition (Figure 5), the second bulkhead 12B is aligned with the hull of the boat, to close the respective perforated passage 13 and restore the continuity of the hull S even with the propeller 6 extracted.

Thus advantageously the hydrodynamic drag coefficient in both conditions is improved.

In order to enable the transition of the propeller 6 (and/or of the shaft 8) between the two conditions, actuation means are provided, preferably electric, such as for example an electric motor for actuating and adapted guides and slides, which are conventional and will not be further discussed here.

Turning now to the general, optional and advantageous features of each propulsion device 3, note that it comprises a housing 4 which is accommodated inside the hull, in order to accommodate at least the propeller assembly 6 in the inactive condition.

As can be seen in the detail in Figure 6, the housing 4 is a watertight seal, so as to define the inner accommodation chamber in which the propeller assembly 6 and the shaft 8 are arranged in the inactive condition.

Advantageously, as an option, the housing 4 comprises a coupling flange 15 for a duct of a cleaning liquid and a diffuser for the cleaning liquid which is directed toward the inside of the housing 4.

The cleaning liquid could be for example fresh water (optionally with the addition of a washing agent) which is sprayed on the propeller assembly 6 when it is in the inactive condition, accommodated in the housing, in order to clean it of sea water and of any dirt or vegetation that may form thereupon, thus extending its useful life and reducing the need for maintenance.

In this sense it is possible to note that, if the bulkheads 12A and 12B (or at least the bulkhead 12A) are adapted to define a watertight closure, then it is possible to achieve, at the same time, a considerable saving of the cleaning liquid used (particularly important when this is fresh water originating from a tank on the boat), since it is possible to perform the cleaning while keeping the propeller assembly immersed in the chamber proper for the necessary period of time, thus avoiding waste; when the cleaning action is considered concluded it is possible to discharge the cleaning liquid into the sea.

Another possibility to carry out the cleaning of the housing 4 containing the propeller is to convey the exhaust gases of the boat's endothermic motor to the housing proper.

Consequently, another object of the invention is an inboard propulsion unit 2 for a boat 1, which comprises:

- a housing 4 designed to be fitted inside a hull of a boat at a perforated passage 13 which is provided in the hull, the housing 4 being provided with a passage port 4A which can be aligned with the perforated passage 13;

- a propeller assembly 6, which can be shifted between an active condition in which it is extracted from the housing 4, and an inactive condition, in which it is accommodated in the housing 4;

- an electric motor for driving the propeller assembly.

According to an improvement, the inboard propulsion unit 2 comprises the supporting shaft 8 which supports, at one of its ends, the propeller assembly 6, which comprises a propeller 6A which is coupled to the supporting shaft 8, at a free end thereof, the propeller assembly 6 comprising a first bulkhead 12A which is provided on the side of the propeller 6A that lies opposite the one coupled to the supporting shaft 8, and a second bulkhead 12B which is arranged substantially transversely on the supporting shaft 8 and is parallel to the first bulkhead 12A, so that:

- when the propeller assembly 6 is in the inactive condition, the first bulkhead 12A closes the passage port 4A of the housing 4, preferably creating a watertight closure;

- when the propeller assembly 6 is in the active condition, the second bulkhead 12B closes the passage port 4A of the housing 4, preferably creating a watertight closure.

Figures 7-10 show a second embodiment of the propulsion unit 2 according to the invention.

In such embodiment the propulsion unit 2 comprises the housing 4 similarly to the previous embodiment and the propeller assembly, now designated with the reference numeral 26 and constituted by the propeller 26A and by the supporting shaft 28 inside which a shaft 30, supported by bearings 31-33, for actuating the propeller 26A is accommodated.

The shaft 30 is driven by a motor 40.

Also in the second embodiment, the propeller assembly 26 can be shifted between an active condition in which it is extracted from the housing 4, and an inactive condition, in which it is accommodated in the housing 4.

Differently from the previous embodiment, the propeller assembly 26 is configured so that the propeller can be positioned along the shaft 8, as illustrated in Figure 8, and therefore it can be retracted into the housing 4 (and into the hull of the boat), thus making it possible to have an opening or passage 13 of reduced dimensions and therefore not excessively invasive for the boat.

Conveniently, furthermore, the propeller assembly 26 can be rotated so as to bring the propeller 26A into many active conditions, at different angles from the longitudinal axis of the boat.

To this end the propeller assembly 26 comprises, fitted on the shaft 8, a disk-like element 35, constituted preferably by a pair of disks, which is provided on the lateral surface with a rack that allows the engagement of a pinion 36 of a motor 37.

The motor 37 makes it possible to rotate, by way of the rack, the propeller assembly 26 so as to change the position of the propeller 26A. It is therefore possible for example to rotate the propeller 26A so that it is arranged with the vanes in the direction of the bow-stern axis of the boat, so as to enable lateral movements of the boat, or according to any other angle with respect to the longitudinal axis of the boat.

In an additional variation, not shown, aimed at reducing the space taken up by the housing 4, the propeller 26A can be raised into the housing so that it comes into abutment with a locator defined inside the housing 4, so as to angle it and enable its storage inside the housing in an angular position.

In this manner the propeller 26 A occupies less space than the propeller in the vertical position, and therefore the housing 4 can be made with reduced dimensions.

Each one of the propulsion units 2 of the first embodiment can be provided according to what is described for the second embodiment.

Similarly, another object of the invention is a boat 1, preferably a sailing boat, which comprises an inboard propulsion unit 2 according to the foregoing description.

Operation of the invention is clear and evident from the foregoing description.

In practice it has been found that the inboard propulsion unit 2 and/or the boat 1 , according to the present invention, achieve the intended aim and objects since they can profitably be used even when the boat is listing.

Another advantage consists in having an inboard propulsion unit 2 and/or a boat 1, according to the invention, that requires little maintenance.

Another advantage consists in having an inboard propulsion unit and/or a boat, according to the invention, that are easy to clean.

The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

Moreover, all the details may be substituted by other, technically equivalent elements.

In practice the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. 102017000046071 from which this application claims priority are incorporated herein by reference.

Where the technical features mentioned in any claim are followed by reference numerals and/or signs, those reference numerals and/or signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference numerals and/or signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference numerals and/or signs.

Claims

1. In a boat (1), an inboard propulsion unit (2),

characterized in that

the propulsion unit (2) comprises two electric propulsion devices (3), each one provided at least with:

- a propeller assembly (6), which can be moved between an active condition, in which it protrudes downward from the hull (S), and an inactive condition, in which it is contained inside the hull (S);

- an electric motor for driving the propeller assembly (6);

- wherein the propeller assemblies (6) of the electric propulsion devices (3), in the active condition, are extended at an angle with respect to a central plane of symmetry (Y) of the hull (S) of the boat (1).

2. The propulsion unit (2) according to claim 1 , characterized in that each electric propulsion device (3) comprises a respective supporting shaft (8) which supports, at one of its ends, the propeller assembly (6), said propeller assembly (6) comprising a propeller (6A) which is coupled to the supporting shaft (8), at a free end thereof.

3. The propulsion unit (2) according to claim 1 or 2, characterized in that the propeller assembly (6) comprises a first bulkhead (12A) which is provided on the side of the propeller (6A) that lies opposite the one that is coupled to the supporting shaft (8), and a second bulkhead (12B) which is arranged substantially transversely on the supporting shaft (8) and is parallel to the first bulkhead (12A).

4. The propulsion unit (2) according to one or more of the preceding claims, characterized in that the supporting shaft (8) can translate along a direction of motion (M) in order to allow the transition of the respective propeller assembly (6) between the active condition and the inactive condition, and vice versa, said direction of motion (M) lying on a substantially vertical plane, with the boat in the active configuration , and being inclined with respect to said central plane of symmetry (Y) of the hull (S) of the boat (l).

5. The propulsion unit (2) according to one or more of the preceding claims, characterized in that on the hull (S) of the boat, for each propulsion device (3) there is a perforated passage (13) to allow the transition at least of the propeller assembly (6) between the inactive condition and the active condition, and wherein:

- when a propeller assembly (6) is in the inactive condition, the first bulkhead (12A) is aligned with the hull of the boat, to close the respective perforated passage (13);

- when a propeller assembly (6) is in the active condition, the second bulkhead (12B) is aligned with the hull of the boat, to close the respective perforated passage (13).

6. The propulsion unit (2) according to one or more of the preceding claims, characterized in that it comprises a housing (4) which is accommodated inside the hull, in order to accommodate at least said propeller assembly (6) in the inactive condition.

7. The propulsion unit (2) according to one or more of the preceding claims, characterized in that said housing (4) comprises a coupling flange (15) for a duct of a cleaning liquid and a diffuser for the cleaning liquid which is directed toward the inside of the housing (4).

8. An inboard propulsion unit (2) for a boat (1), which comprises:

- a housing (4) designed to be fitted inside a hull of a boat at a perforated passage (13) which is provided in said hull, said housing (4) being provided with a passage port (4A) which can be aligned with said perforated passage (13);

- a propeller assembly (6; 26), which can be shifted between an active condition in which it is extracted from the housing (4), and an inactive condition, in which it is accommodated in the housing (4);

- an electric motor for driving the propeller assembly.

9. The inboard propulsion unit (2) according to claim 8, characterized in that it comprises a supporting shaft (8) which supports the propeller assembly (6) at one of its ends, said propeller assembly (6) comprising a propeller (6A) which is coupled to the supporting shaft (8), at a free end thereof, said propeller assembly (6) comprising a first bulkhead (12A) which is provided on the side of the propeller (6A) that lies opposite the one coupled to the supporting shaft (8), and a second bulkhead (12B) which is arranged substantially transversely on the supporting shaft (8) and is parallel to the first bulkhead (12A), so that:

- when the propeller assembly (6) is in the inactive condition, the first bulkhead (12A) closes the passage port (4 A) of the housing (4);

- when the propeller assembly (6) is in the active condition, the second bulkhead (12B) closes the passage port (4A) of the housing (4).

10. The inboard propulsion unit (2) according to claim 8, characterized in that it comprises a supporting shaft (28) which supports the propeller assembly (26) at one of its ends, said propeller assembly (26) comprising a propeller (26A) which is coupled to the supporting shaft (28), at a free end thereof, said propeller (26A) being positionable in axial alignment with said supporting shaft (28) for the retraction of said propeller (26 A) inside said housing (4).

11. The inboard propulsion unit (2) according to claim 8, characterized in that the propeller assembly (26) comprises, fitted on the shaft (28), a disk-like element (35), which is provided on the lateral surface with a rack that allows the engagement of a pinion (36) of a motor (37), said motor (37) making it possible to rotate, by means of the rack, the propeller assembly (26) so as to change the position of the propeller (26A).

12. A boat (1), characterized in that it comprises an inboard propulsion unit (2) according to one or more of the preceding claims.