Propulsion unit for motor boats

Description

[0001] The present invention generally relates to motor boats, and particularly, a propulsion unit for these boats.

[0002] In all transmissions for nautical use, except those of stern outdrive type, the propeller axis is inclined by a certain angle α relative to the water line WL of the boat. This condition is schematically represented in Fig. 8, which illustrates a propulsion system with a submerged propeller according to the prior art.

[0003] It can be seen that the thrust generated by the propeller is directed as the axis thereof, and thus - since the axis is inclined, a part of the thrust destined to propulsion is lost because a component is present, which is normal to the forward direction of the boat.

[0004] The case of surface propeller transmissions, particularly when applied to fast planing hulls, is however the most significant as the design operating condition provides that the small sized propeller hub is kept out of water in order to decrease the frictional resistance, and thus only the lower blades of the propeller are submerged. Some examples of prior art fast hulls with surface propeller transmissions are represented in Fig. 9A and 9B. In this case, the inclination angle a can be less sharp as compared with the submerged propeller transmission, but this is still considerable relative to the thrust fraction normal to the forward direction of the boat.

[0005] The ideal condition, i.e. a propeller having a horizontal (or almost horizontal) axis is difficult to obtain because it is in contrast with the actual feasibility of installing the engine and reversing gearbox onboard the hull. For example, there may be interference problems between a reversing gearbox or an engine oil pan and the hull bottom.

[0006] To partially solve these installation problems, in order to obtain a particularly small angle α, the engine and reversing gearbox must be advanced using cardan joints (also segmented) or homokinetic joints. This solution, however, entails a bad use of the space onboard the hull (larger engine room), and especially the advance of the barycenter of the boat with consequent slowing down.

[0007] In addition to these drawbacks, a common basic problem with all marine transmissions, including those of the stern outdrive type is the corrosion of the submerged parts. Using the top-quality materials made available from the technological development and properly grounding all the metallic components may not be sufficient to obtain full protection from corrosion. It is thus desirable that the number of submerged components is reduced as much as possible.

[0008] US-6361387 discloses some embodiments of a marine propulsion system comprising a single engine and a transmission group which drives a pair of shafts for submerged propellers. The single output shaft of the engine extends in a forward direction and the transmission group, of the belt drive type, is placed at the front of the engine. The driving shafts of the propellers extend in a rearward direction and in parallel relationship with the bottom of the hull and/or the water level.

[0009] In view of the above, the object of the present invention is to provide a propulsion unit for motor boats which allows considerably reducing, or even setting to zero, the inclination of the propeller axis relative to the waterline of the boat.

[0010] Another object of the present invention is to provide a propulsion unit for motor boats allowing the parts exposed to the corrosive action of water to be limited.

[0011] A further object of the present invention is to provide a propulsion unit that can be easily installed on any type of motor boat, independently of the configuration of the transmission (either V-Drive or in-line), either with submerged propeller or surface propeller.

[0012] These objects are achieved by the present invention due to a propulsion unit for boots according to claim 1. further peculiar features of the present invention are set forth in the dependent claims.

[0013] A propulsion unit according to the present invention, which is provided with a drive member allowing to lower the drive shaft to be as close as possible to the hull bottom, allows obtaining an inclination of the propeller axis which is either very close to 0°, or however forms a very small angle, normally less than 4°, relative to the water line of the boat.

[0014] The drive member is preferably mounted inside the hull close to the transom, whereas at least one propeller mounted close to the transom of the hull is provided on the outside, the hub of which has a radius substantially equal to the distance between the axis of the output shaft and the outer wall of the hull bottom.

[0015] The propulsion unit according to the present invention is further suitable for different embodiments, such as that in which the reversing gearbox is integrated within the drive member.

[0016] Furthermore, a propulsion unit according to the invention may advantageously comprise means for changing, in a controlled manner, the inclination of the output shaft axis relative to the waterline of the boat.

[0017] The invention further relates to a boat being provided with a propulsion unit of the type cited above. For example, the boat can be either provided with a G-Drive transmission, with the reversing gearbox being directly mounted on the drive member, or a V-Drive transmission (with the engine and reversing gearbox being placed above the propeller axis) or Ring-Drive transmission (similar to V-Drive but with closed loop, with the engine being supported by the transmission).

[0018] According to the present invention, horizontal axes (or small inclination angles) can be obtained for the propeller, and the problems of installing power units onboard a hull (mainly with deep V planing bottoms) can also be reduced.

[0019] The submerged metallic parts are further reduced by adopting a propeller having a hub of a greater size than a conventional one, and a drive member mounted in proximity of the transom, because the long drive shaft projecting down into the water as well as the support thereof can be avoided.

[0020] Further characteristics and advantages of the present invention will appear more clearly from the description below, which is to be considered as being illustrative and non-limiting, with reference to the annexed schematic drawings, in which:

• Figs. 1A and 1B are longitudinal sectional views of possible embodiments of a propulsion unit according to the present invention, which is installed in proximity of the transom of a boat;
• Fig. 2 is a schematic elevation view of the stern portion of a boat being provided with a pair of propulsion units according to the present invention;
• Fig. 3 is a longitudinal section view of another possible embodiment of a propulsion unit according to the present invention;
• Fig. 3A is a cross-section view illustrating the arrangement of the gears in the propulsion unit represented in fig. 3;
• Fig. 4 is an enlarged view of a detail from Fig. 3;
• Fig. 5 is a longitudinal section view of possible arrangement of the propulsion unit according to the present invention;
• Fig. 6 is a longitudinal section view of a further possible embodiment of a propulsion unit according to the present invention;
• Figs. 7A-7C illustrate possible applications of a propulsion unit according to the present invention to a V-Drive and Ring-Drive transmission, respectively; and
• figs. 8, 9A and 9B illustrate several embodiments of the propulsion units according to the prior art.

[0021] In Fig. 1 is illustrated a drive member 10 without gears and mounted close to the transom 20 of a boat. To the drive member 10 there is output-connected a propeller 30 having a hub 31 of a greater size than those generally used in known propellers. Particularly, the hub 31 has a radius R substantially equal to the distance H between the axis A, which is common to the propeller 30 and the output shaft from drive member 10, and the hull bottom.

[0022] In Fig. 1B is schematically represented a possible embodiment of a drive member 110 of the type having gears. One or two power takeoffs can be provided on the side facing the reversing gearbox, the one upper 111 and the other lower 112, which are connected to each other by a pair of respective gears 113 and 114.

[0023] The lower power takeoff 112 is co-axial with the output axis A, and together with the upper power takeoff, advantageously allows connecting the member 110 with any existing reversing gearbox, without requiring dedicated reversing gearboxes or however means for adapting the connection. This does not exclude, however, the possibility that (homokinetic or cardan) joints are used to connect the reversing gearbox to the member 110 when this is required in order to take advantage of the zero or reduced inclination of axis A.

[0024] Accordingly, one of the peculiar features of the drive member 10 is that it has a very low axis A exiting from the stern, and consequently, the angle formed between this axis and the waterline WL is about 0°, or however not greater than 4°.

[0025] As represented by way of example in the view from Fig. 2, the hub 31 of each propeller 30 thus comes to be always out of the dynamic waterline WL, preferably working as a surface propeller, where only the lower blades 32, with planing hull, come in contact with water.

[0026] A propeller 30 having a hub with a greater diameter than a traditional one allows using the propeller axis having an inclination which is either zero or not greater than about 4° in an optimum manner. This further allows reducing the projection of the propulsion unit relative to the transom 20, and simultaneously reducing the number of metallic parts being in direct contact with water and reducing the drag.

[0027] In other words, the diameter of the hub 31 of a propeller being mounted very close to the transom 20 is such to lap by its lower part, in height, the hull bottom 21, such as to have, practically, a propeller 30 in which only the lower blades 32 project to the water relative to the hull bottom 21.

[0028] The propulsion unit described above can be as well applied to single-engine or double-engine equipment. In the latter case, or however with an even number of motors, the equipment is particularly advantageous, as the contrarotating propellers altogether cancel the torque generated by each engine or propeller. The single-propeller solution, also in the version of Fig. 1B with two power takeoffs 111 and 112 stands out for its compactness.

[0029] In Figs. 3 and 3A, an embodiment of the invention is represented as being applied to a type of transmission with two co-axial and contrarotating propellers 30 and 35. This solution is more advantageous than the single-propeller version discussed above, because the torques generated by the propellers - equal and opposite - are "automatically" cancelled and this is ideal for single-engine applications and optimum for equipment with any number of motors (two, three, four, etc.), also offering a greater acceleration and retrieving the energy dissipated in the rotary motion imparted to the water by the first propeller.

[0030] The gear drive member 210 of the double-propeller version is different from those already described above, since it has a hollow shaft 215 that houses a co-axial shaft 213 therein. The two co-axial shafts 213 and 215 transmit a contrarotating movement to respective propellers 30 and 35.

[0031] Counter-rotation is ensured by a set of gears 211a, 211b and 211c as schematically represented in Fig. 3A. It can be noted that the operation of the contrarotating propulsion unit is ensured independently of the power takeoff selected for use, i.e. the upper power takeoff 218 connected to the gear 221 a, or the lower power takeoff 216 connected to the gear 211c.

[0032] The provision of a gear drive member with a drive shaft for each propeller also allows, when desired, selecting a different gear ratio for each propeller, by changing the size and number of teeth of the gears. Unlike other double-propeller systems, such as "duo-prop" stern outdrives, the contrarotating propellers of a propulsion unit according to the present invention can make a different number of revolutions.

[0033] In the view from Fig. 3, a duct 51 can be seen which is provided for the engine exhaust gas. The engine exhaust gas can be caused to pass through the hub of the propellers 30 and 35. To the purpose, the bottom of the hub is preferably provided with holes.

[0034] A duct 52 to vent the propellers 30 and 35, i.e. to suck the air from above the water surface in the vicinity of the propellers may be also provided.

[0035] The two contrarotating co-axial shafts 213 and 215 can be differently supported. A possible solution, which is particularly interesting, is that wherein both shafts are supported by means of rubber bushes 212 and 214 that are dynamically lubricated with sea water. To obtain this result, the propulsion unit provides a dynamic intake 250 that forces the water to enter the open lubrication "circuit". A face seal is provided upstream, i.e. towards the transom 20, for each shaft. This solution is more advantageous relative to the traditional use of cages and oil bath bearings because it eliminates these components.

[0036] It is possible, however, to adopt a hybrid solution, i.e. the one of the two shafts being supported by water-lubricated bush and the other shaft being supported by oil bath bearings and cages.

[0037] The solution providing the shaft as being supported by means of a rubber bush, and forced lubrication with a dynamic water intake can be however adopted also for the single-propeller embodiments already described with reference to Figs. 1A and 1B. Alternatively, the single-propeller drive shaft can be however supported with oil-bath bearings.

[0038] A gear drive member according to the present invention, from which the shaft (or the two co-axial shafts) to which the propeller is fixed can be directly mounted close to the transom 20 due to a round hole made on the transom.

[0039] Fig. 4 illustrates an enlarged detail from Fig. 3 in which elastic sealing elements 220 are seen, such as rubber O-rings having a big section, and through holes 230 for fixing the propulsion unit to the hull by means of nuts and screws. The provision of rubber sealing rings 220 allows using their capacity to deformation in order to obtain the possibility of slightly changing the inclination of the propulsion unit by means of rotation about an axis 280.

[0040] Fig. 5 illustrates another embodiment of a propulsion unit according to the present invention. The gear drive member 310 as represented therein particularly comprises an envelope having a substantially spherical fitting portion 330 for the drive shaft(s) to pass therethrough. The spherical portion 330 is housed in a correspondingly sized and shaped seat, which is provided for example by a pair of concave flanges 340 that are fixed to the transom 20. A bellow-like elastic element 320 ensures the seal at the outlet hole of the propulsion unit from the transom. Similar to the embodiment discussed above, the inclination of the propulsion unit can be changed by some degrees relative to the waterline WL of the boat by causing it to rotate about an axis 380. This embodiment can be particularly advantageous because the whole system can be disassembled after installation, either when needed or in order to carry out the periodical maintenance and/or overhaul operations.

[0041] A further advantageous feature of the embodiment shown in Fig. 5 is that it allows the inclination of the propulsion unit to be significantly changed. Practically, suitable actuators can be provided, which can be operated in a controlled manner, and are capable of imparting a rotation about an axis 380.

[0042] An actuator that can be used for this application can be, for example, of a hydraulic, electrical or electro-hydraulic type, being arranged within the hull and thus not exposed to corrosion or inadvertent damage.

[0043] The actuator (not shown) can be fixed at one end thereof to a fixed part of the boat, such as integral with the transom, whereas the opposite end can be fixed to the gearbox.

[0044] In the embodiments described above, the gear drive member is a separate element relative to the reversing gearbox that is normally associated with each engine. In fig. 6 there is represented a further embodiment in which the gear drive member 410 and the reversing gearbox 490 are integrated in a single element 400.

[0045] The propulsion unit described herein is particularly suitable to be applied to fast hulls, both planing and displacement ones, either mono-hull or catamaran, with any number of engines.

[0046] Several exemplary applications of the propulsion unit according to the present invention to boats provided with different transmissions are illustrated in Fig. 7A-7C.

[0047] In Fig. 7A there is illustrated a V-Drive propulsion system with engine 50 and reversing gearbox 40 placed above the propeller(s) axis. The engine 50 and the reversing gearbox 40 are connected to the lower power takeoff of a gear drive member 210 through a shaft 60 being provided with suitable cardan or homokinetic joints 61 at the ends thereof.

[0048] In Fig. 7B, a Ring-Drive transmission (similar to the V-Drive but with closed loop) is illustrated in which the engine 50 and the reversing gearbox 40 are supported by the same drive member 210, with the reversing gearbox 40 being connected to the upper power takeoff of the drive member 210. In Fig. 7C, a Ring-Drive transmission is again illustrated, in which, however, the engine 50 is connected to an element 400 which integrates both the reversing gearbox and the gear drive member.

Claims

1. A boat with a propulsion unit, comprising at least one engine (50) and at least one reversing gearbox (40, 490) that are housed within the hull of a boat, and at least one propeller (30, 35) which is driven by said engine (50) and placed outside the hull of said boat, characterized by comprising at least one drive member (10, 110, 210, 310, 410) that is assembled within the bottom (21) of said hull in proximity of the transom (20) and having at least one output shaft (213, 215) with at least one propeller (30, 35) adjusted thereon, and said at least one propeller (30, 35) being assembled in proximity of the transom (20) of said hull, the hub (31) of said at least one propeller (30, 35) having a radius (R) substantially equal to the distance (H) between the axis (A) of said at least one output shaft (213, 215) and the outer wall of the bottom (21) of said hull, the axis (A) of said at least one output shaft (213, 215) being substantially parallel to the waterline (WL) of the boat.

2. The boat according to claim 1, wherein the inclination of the axis (A) of said at least one output shaft (213, 215) relative to the waterline (WL) of the boat ranges between 0° and 4°.

3. The boat according to claim 1, wherein said drive member (10, 110, 210, 310, 410) is assembled close to the transom (20) of said hull.

4. The boat according to claim 1, wherein said drive member (10, 110, 210, 310, 410) comprises at least one power takeoff (111, 112, 216, 218) that is substantially parallel to the axis (A) of said output shaft (213, 215).

5. The boat according to claim 1, wherein said drive member (10, 110, 210, 310, 410) comprises at least one power takeoff (112, 216) that is substantially co-axial with the axis (A) of said output shaft (213, 215).

6. The boat according to claim 1, wherein said drive member (10, 110, 210, 310, 410) is a gear drive member and comprises at least two co-axial output shafts (213, 215) of which at least one (215) is hollow and houses the other (213) therein, and wherein one or more gears (211a, 211b, 211c) are provided in order to rotate said co-axial output shafts (213, 215) in mutually opposite direction.

7. The boat according to claim 6, wherein at least one propeller (30, 35) is provided which is mounted at the end of each of said co-axial output shafts (213, 215), and wherein the hub (31) of said propellers (30, 35) has a radius (R) substantially equal to the distance (H) between the axis (A) of said co-axial output shafts(213, 215) and the outer wall of the bottom (21) of said hull.

8. The boat according to claim 6 or 7, wherein a first one (35) of said propellers is mounted in proximity of the transom (20) and is adjusted to the end of the outer co-axial output shaft (215) and a second one (30) of said propellers is assembled in proximity of said first propeller (35) and adjusted to the end of the inner co-axial output shaft (213).

9. The boat according to claim 6, wherein said gear drive member (210) comprises different gear ratios between said two output shafts (213, 215).

10. The boat according to claim 6, wherein said co-axial output shafts (213, 215) are supported with friction-reducing means (212, 214).

11. The boat according to claim 10, wherein said friction-reducing means include one or more bearings.

12. The boat according to claim 10, wherein said friction-reducing means include one or more bushes (212, 214) with dynamic water-lubrication.

13. The boat according to claim 1, wherein said drive member (10, 110, 210, 310, 410) comprises an outer envelope that is provided with a mounting section suitable to be fitted in a through hole of the transom (20).

14. The boat according to claim 13, wherein the substantially cylindrical mounting section of the envelope of said drive member (10, 110, 210, 410) comprises one or more seats to hold one or more sealing elastic members (220) in position between said mounting section and said hole of the transom (20).

15. The boat according to claim 1, wherein said drive member (310) comprises an outer envelope that is provided with a substantially spherical mounting section (330) suitable to be housed in a correspondingly shaped and sized seat.

16. The boat according to claim 15, wherein said spherical seat housing said spherical mounting section (330) includes one or more flanges (340) being fixed to the transom (20) of the boat.

17. The boat according to claim 1, wherein said reversing gearbox (490) is integrated in said gear drive member (410).

18. The boat according to claim 1, wherein means are provided in order to change, in a controlled manner, the inclination of the axis (A) of said at least one output shaft (213, 215) relative to the waterline (WL) of the boat by an amount ranging between 0° and 4°.

19. The boat according to claim 18, wherein said drive member (210, 310) comprises a control piston in order to change the inclination of the propeller axis (A) relative to the waterline (WL).

20. The boat according to any claim 1-19, wherein said propulsion unit is applied to a transmission with reversing gearbox (40, 490) directly fixed to the propulsion unit.

21. The boat according to any claim 1-19, wherein said propulsion unit is applied to a V-Drive transmission with engine (50) and reversing gearbox (40) being arranged above the propeller axis (A).

22. The boat according to any claim 1-19, wherein said propulsion unit is applied to a Ring-Drive transmission with engine (50) being supported by said propulsion unit.

23. The boat according to any claim 1-19, wherein the hull is a mono-hull or catamaran, either planing or displacement hull.

24. The boat according to any claim 1-19, wherein means (52) are provided to suck the air in the vicinity of said propellers (30, 35) above the waterline (WL) to avoid the phenomenon of cavitation.

Ansprüche

1. Wasserfahrzeug mit einer Antriebseinheit, umfassend mindestens einen Motor (50) und mindestens ein Wendegetriebe (40, 490), welche innerhalb des Rumpfes eines Wasserfahrzeuges untergebracht sind, und mindestens einen Propeller (30, 35), welcher durch den Motor (50) angetrieben wird und außerhalb des Rumpfes des Wasserfahrzeuges angeordnet ist, gekennzeichnet durch Umfassen von mindestens einem Antriebsglied (10, 110, 210, 310, 410), welches innerhalb des Bodens (21) des Rumpfes in der Nähe des Heckspiegels (20) montiert ist und aufweisend mindestens eine Abtriebswelle (213, 215) mit mindestens einem darauf gesetzten Propeller (30, 35), und der mindestens eine Propeller (30, 35) in der Nähe des Heckspiegels (20) des Rumpfes montiert ist, die Nabe (31) des mindestens einen Propellers (30, 35) einen Radius (R) aufweisend, im Wesentlichen gleich dem Abstand (H) zwischen der Achse (A) der mindestens einen Abtriebswelle (213, 215) und der äußeren Wand des Bodens (21) des Rumpfes, wobei die Achse (A) der mindestens einen Abtriebswelle (213, 215) im Wesentlichen parallel zur Wasserlinie (WL) des Wasserfahrzeuges ist.

2. Wasserfahrzeug nach Anspruch 1, wobei die Neigung der Achse (A) der mindestens einen Abtriebswelle (213, 215) relativ zur Wasserlinie (WL) des Wasserfahrzeuges im Bereich zwischen 0° und 4° liegt.

3. Wasserfahrzeug nach Anspruch 1, wobei das Antriebsglied (10, 110, 210, 310, 410) nahe des Heckspiegels (20) des Rumpfes montiert ist.

4. Wasserfahrzeug nach Anspruch 1, wobei das Antriebsglied (10, 110, 210, 310, 410) mindestens einen Abtrieb (111, 112, 216, 218) umfasst, welcher im Wesentlichen parallel zu der Achse (A) der Abtriebswelle (213, 215) ist.

5. Wasserfahrzeug nach Anspruch 1, wobei das Antriebsglied (10, 110, 210, 310, 410) mindestens einen Abtrieb (112, 216) umfasst, welcher im Wesentlichen koaxial zu der Achse (A) der Abtriebswelle (213, 215) ist.

6. Wasserfahrzeug nach Anspruch 1, wobei das Antriebsglied (10, 110, 210, 310, 410) ein Getriebeglied ist und mindestens zwei koaxiale Abtriebswellen (213, 215) umfasst, von welchen mindestens eine (215) hohl ist und die andere (213) darin aufnimmt, und wobei ein oder mehrere Zahnräder (211a, 211b, 211c) bereitgestellt sind, um die koaxialen Abtriebswellen (213, 215) in zueinander entgegengesetzte Richtungen zu drehen.

7. Wasserfahrzeug nach Anspruch 6, wobei mindestens ein Propeller (30, 35) bereitgestellt ist, welcher an das Ende jeder der koaxialen Abtriebswellen (213, 215) montiert ist, und wobei die Nabe (31) der Propeller (30, 35) einen Radius (R) aufweist, welcher im Wesentlichen gleich dem Abstand (H) zwischen der Achse (A) der koaxialen Abtriebswellen (213, 215) und der äußeren Wand des Bodens (21) des Rumpfes ist.

8. Wasserfahrzeug nach Anspruch 6 oder 7, wobei ein erster (35) der Propeller in der Nähe des Heckspiegels (20) montiert und an das Ende der äußeren koaxialen Abtriebswelle (215) gesetzt ist, und ein zweiter (30) der Propeller in der Nähe des ersten Propellers (35) montiert ist und an das Ende der inneren koaxialen Abtriebswelle (213) gesetzt ist.

9. Wasserfahrzeug nach Anspruch 6, wobei das Getriebeglied (210) verschiedene Getriebeübersetzungen zwischen den zwei Abtriebswellen (213, 215) umfasst.

10. Wasserfahrzeug nach Anspruch 6, wobei die koaxialen Abtriebswellen (213, 215) mit Hilfsmitteln (212, 214) zur Verringerung der Reibung gelagert werden.

11. Wasserfahrzeug nach Anspruch 10, wobei die Hilfsmittel zur Verringerung der Reibung ein oder mehrere Lager einschließen.

12. Wasserfahrzeug nach Anspruch 10, wobei die Hilfsmittel zur Verringerung der Reibung eine oder mehrere Lagerbuchsen (212, 214) mit dynamischer Wasserschmierung einschließen.

13. Wasserfahrzeug nach Anspruch 1, wobei das Antriebsglied (10, 110, 210, 310, 410) eine äußere Ummantelung umfasst, welche mit einem Montageabschnitt bereitgestellt ist, welcher geeignet ist, in eine Durchgangsbohrung des Heckspiegels (20) eingesetzt zu werden.

14. Wasserfahrzeug nach Anspruch 13, wobei der im wesentlichen zylindrische Montageabschnitt der Ummantelung des Antriebsglieds (10, 110, 210, 410) eine oder mehrere Aufnahmen umfasst, um ein oder mehrere elastische Dichtungselemente (220) in Position zwischen dem Montageabschnitt und der Bohrung des Heckspiegels (20) zu halten.

15. Wasserfahrzeug nach Anspruch 1, wobei das Antriebsglied (310) eine äußere Ummantelung umfasst, welche bereitgestellt ist mit einem im Wesentlichen kugelförmigen Montageabschnitt (330), welcher geeignet ist, in eine entsprechend geformte und bemessene Aufnahme eingesetzt zu werden.

16. Wasserfahrzeug nach Anspruch 15, wobei die kugelförmige Aufnahme, den kugelförmigen Montageabschnitt (330) aufnehmend, einen oder mehrere Flansche (340) einschließt, welche am Heckspiegel (20) des Wasserfahrzeuges befestigt sind.

17. Wasserfahrzeug nach Anspruch 1, wobei das Wendegetriebe (490) in das Getriebeglied (410) integriert ist.

18. Wasserfahrzeug nach Anspruch 1, wobei Hilfsmittel bereitgestellt sind, um auf kontrollierte Weise die Neigung der Achse (A) der mindestens einen Abtriebswelle (213, 215) relativ zur Wasserlinie (WL) des Wasserfahrzeuges um einen Betrag im Bereich zwischen 0° und 4° zu verändern.

19. Wasserfahrzeug nach Anspruch 18, wobei das Antriebsglied (210, 310) einen Steuerkolben umfasst, um die Neigung der Propellerachse (A) relativ zur Wasserlinie (WL) zu verändern.

20. Wasserfahrzeug nach einem der Ansprüche 1-19, wobei die Antriebseinheit angewendet wird auf einen Antrieb mit unmittelbar an die Antriebseinheit angebrachtem Wendegetriebe (40, 490).

21. Wasserfahrzeug nach einem der Ansprüche 1-19, wobei die Antriebseinheit auf einen Antrieb mit V-Antrieb angewendet wird und der Motor (50) und das Wendegetriebe (40) oberhalb der Propellersachse (A) angeordnet sind.

22. Wasserfahrzeug nach einem der Ansprüche 1-19, wobei die Antriebseinheit auf einen Ring-Drive-Antrieb angewendet wird und der Motor (50) von der Antriebseinheit getragen wird.

23. Wasserfahrzeug nach einem der Ansprüche 1-19, wobei der Rumpf ein Monorumpf oder ein Katamaran ist und entweder ein Gleit- oder ein Verdrängerrumpf ist.

24. Wasserfahrzeug nach einem der Ansprüche 1-19, wobei Hilfsmittel (52) bereitgestellt sind, im die Luft in der Umgebung der Propeller (30, 35) oberhalb der Wasserlinie (WL) anzusaugen, um das Phänomen der Kavitation zu vermeiden.

Revendications

1. Bateau avec une unité de propulsion, comprenant au moins un moteur (50) et au moins un mécanisme de renversement de marche (40, 490) qui sont logés dans la coque d'un bateau, et au moins une hélice (30, 35) qui est entraînée par ledit moteur (50) et placée à l'extérieur de la coque dudit bateau, caractérisé par le fait qu'il comprend au moins un élément d'entraînement (10, 110, 210, 310, 410) qui est assemblé dans le fond (21) de ladite coque à proximité du tableau arrière (20) et ayant au moins un arbre de sortie (213, 215) sur lequel au moins une hélice (30, 35) est ajustée, et ladite au moins une hélice (30, 35) est assemblée à proximité du tableau arrière (20) de ladite coque, le moyeu (31) de ladite au moins une hélice (30, 35) présentant un rayon (R) sensiblement égal à la distance (H) entre l'axe (A) dudit au moins un arbre de sortie (213, 215) et la paroi extérieure du fond (21) de ladite coque, l'axe (A) dudit au moins un arbre de sortie (213, 215) étant sensiblement parallèle à la ligne de flottaison (WL) du bateau.

2. Bateau selon la revendication 1, dans lequel l'inclinaison de l'axe (A) dudit au moins un arbre de sortie (213, 215) par rapport à la ligne de flottaison (WL) du bateau est comprise entre 0 ° et 4°.

3. Bateau selon la revendication 1, dans lequel ledit élément d'entraînement (10, 110, 210, 310, 410) est assemblé à proximité immédiate du tableau arrière (20) de ladite coque.

4. Bateau selon la revendication 1, dans lequel ledit élément d'entraînement (10, 110, 210, 310, 410) comprend au moins une prise de force (111, 112, 216, 218) qui est sensiblement parallèle à l'axe (A) dudit arbre de sortie (213, 215).

5. Bateau selon la revendication 1, dans lequel ledit élément d'entraînement (10, 110, 210, 310, 410) comprend au moins une prise de force (112, 216) qui est sensiblement coaxiale avec l'axe (A) dudit arbre de sortie (213, 215).

6. Bateau selon la revendication 1, dans lequel ledit élément d'entraînement (10, 110, 210, 310, 410) est un élément d'entraînement par engrenages et comprend au moins deux arbres de sortie coaxiaux (213, 215) dont l'un au moins (215) est creux et loge l'autre (213) à l'intérieur, et dans lequel un ou plusieurs engrenages (211a, 211b, 211c) sont disposés afin de faire tourner lesdits arbres de sortie coaxiaux (213, 215) dans des sens mutuellement opposés.

7. Bateau selon la revendication 6, dans lequel il est fourni au moins une hélice (30, 35) qui est montée au niveau de l'extrémité de chacun desdits arbres de sortie coaxiaux (213, 215), et dans lequel le moyeu (31) desdites hélices (30, 35) présente un rayon (R) sensiblement égal à la distance (H) entre l'axe (A) desdits arbres de sortie coaxiaux (213, 215) et la paroi extérieure du fond (21) de ladite coque.

8. Bateau selon la revendication 6 ou 7, dans lequel une première (35) desdites hélices est montée à proximité du tableau arrière (20) et est ajustée sur l'extrémité de l'arbre de sortie coaxial extérieur (215), et la seconde (30) desdites hélices est assemblée à proximité de ladite première hélice (35) et est ajustée sur l'extrémité de l'arbre de sortie coaxial intérieur (213).

9. Bateau selon la revendication 6, dans lequel ledit élément d'entraînement par engrenages (210) comprend différents rapports d'engrenages entre lesdits deux arbres de sortie (213, 215).

10. Bateau selon la revendication 6, dans lequel lesdits arbres de sortie coaxiaux (213, 215) sont supportés par des moyens de réduction des frottements (212, 214).

11. Bateau selon la revendication 10, dans lequel lesdits moyens de réduction des frottements comprennent un ou plusieurs paliers.

12. Bateau selon la revendication 10, dans lequel lesdits moyens de réduction des frottements comprennent une ou plusieurs bagues (212, 214) avec une lubrification dynamique à l'eau.

13. Bateau selon la revendication 1, dans lequel ledit élément d'entraînement (10, 110, 210, 310, 410) comprend une enveloppe extérieure qui est dotée d'une partie de montage appropriée pour être ajustée dans un trou traversant du tableau arrière (20).

14. Bateau selon la revendication 13, dans lequel la partie de montage sensiblement cylindrique de l'enveloppe dudit élément d'entraînement (10, 110, 210, 410) comprend un ou plusieurs sièges pour supporter un ou plusieurs éléments élastiques d'étanchéité (220) en position entre ladite partie de montage et ledit trou du tableau arrière (20).

15. Bateau selon la revendication 1, dans lequel ledit élément d'entraînement (310) comprend une enveloppe extérieure qui est dotée d'une partie de montage sensiblement sphérique (330) appropriée pour être logée dans un siège qui présente une forme et des dimensions correspondantes.

16. Bateau selon la revendication 15, dans lequel ledit siège sphérique logeant ladite partie de montage sphérique (330) comprend une ou plusieurs brides (340) fixées au tableau arrière (20) du bateau.

17. Bateau selon la revendication 1, dans lequel ledit mécanisme de renversement de marche (490) est intégré dans ledit élément d'entraînement par engrenages (410).

18. Bateau selon la revendication 1, dans lequel des moyens sont prévus de manière à modifier, d'une façon commandée, l'inclinaison de l'axe (A) dudit au moins un arbre de sortie (213, 215) par rapport à la ligne de flottaison (WL) du bateau d'une quantité qui est comprise entre 0 ° et 4 °.

19. Bateau selon la revendication 18, dans lequel ledit élément d'entraînement (210, 310) comprend un piston de commande qui permet de modifier l'inclinaison de l'axe de l'hélice (A) par rapport à la ligne de flottaison (WL).

20. Bateau selon l'une quelconque des revendications 1 à 19, dans lequel ladite unité de propulsion est appliquée à une transmission dotée d'un mécanisme de renversement de marche (40, 490) fixé directement à l'unité de propulsion.

21. Bateau selon l'une quelconque des revendications 1 à 19, dans lequel ladite unité de propulsion est appliquée à une transmission en V (V - Drive), un moteur (50) et un mécanisme de renversement de marche (40) étant agencés au-dessus de l'axe de l'hélice (A).

22. Bateau selon l'une quelconque des revendications 1 à 19, dans lequel ladite unité de propulsion est appliquée à une transmission en anneau (Ring - Drive), un moteur (50) étant supporté par ladite unité de propulsion.

23. Bateau selon l'une quelconque des revendications 1 à 19, dans lequel la coque est une monocoque ou un catamaran, planant ou à déplacement.

24. Bateau selon l'une quelconque des revendications 1 à 19, dans lequel des moyens (52) sont prévus pour aspirer l'air à proximité desdites hélices (30, 35) au-dessus de la ligne de flottaison (WL) de manière à éviter un phénomène de cavitation.

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