Advanced boat motorization device

Abstract

A motorization device (10) for a boat (3) is capable of being mounted on a boat (3) around a connecting member (12) allowing at least two rotations in independent directions including a yaw direction (Z) of the boat. The motorization device comprises - a power module (14), capable of housing at least one battery; - a motor unit (16) comprising at least one electric motor electrically connected to said power module; and - a bar-forming member (20), of elongated shape, having a proximal portion, close to the connecting member (12), fixed to the power module (14), and a distal portion, at a distance from the pivot connection (12), carrying the motor unit (16) so that the motor unit is arranged at a distance from the power module (14); the motor unit (16) comprising an output shaft on which at least one propeller (18) is secured. Figure for abstract: Figure 2

Description

Title of the invention: Improved motorization device for a boat 1. Field of the invention

[0001] The invention relates to the field of boat motorization, and more particularly aims at an improved boat motorization device. This device is designed in particular to equip small and medium-sized boats: pirogue, rowboat, inflatable canoe, etc. 2. Prior art

[0002] For this type of boat, two main families of removable motorization are known: outboard type motorizations (hereinafter called outboard), and “long tail” type motorizations (hereinafter called “long-tail”, their generic name in English).

[0003] The outboard motor consists of an assembly formed by a motor driving a propeller, the assembly being fixed to the rear of a boat, partly outside the hull. Although the outboard motor has a small footprint, its proper operation requires a significant draft, at least 50 cm. This makes the outboard inefficient in shallow waterways, or in the presence of shoals. In addition, outboard motors are mostly thermal, and consequently polluting and noisy (80 to 100dB). This is all the more true since the standards for thermal engines in the automobile industry do not apply to outboard motors. Finally, outboards can only be fixed to the rear of a boat, and are therefore not compatible with all boats, in particular boats typical of Southeast Asia.

[0004] We certainly know of outboard motors with electric motors, but these do not solve the problem of the need for draft, nor that of necessarily fixing them to the rear of the boat.

[0005] [Fig.l] illustrates the operating principle of long-tail motors. This type of motor consists of a turret 1 mounted via a double pivot 2 on a boat 3 and carrying a thermal engine 4 arranged at the top of the turret 1. The double pivot 2 allows the rotation of the long-tail motor 1 along at least two independent axes of rotation, including at least the yaw direction of the boat. The turret further comprises a boom 5 - hence the name long tail - at the end of which is mounted a propeller 6. The propeller is driven directly by the thermal engine 4 via a shaft housed in the boom 5 or forming said boom 5, without any additional transmission member or gear. When the thermal engine 4 is in operation, the propeller 6 propels the boat, the direction adjustment being carried out by a user 7 by pivoting the turret 1. Due to its simple design, the thermal engine of the long-tails has no gearbox, and the modulation of the propulsion force and therefore the speed of the boat is done using a carburetion lever.

[0006] Long-tail motorization is a very popular solution, especially in Southeast Asia. This popularity is explained by its simple design, its adaptability to a wide variety of boats, especially those on which it is not possible to attach an outboard motor, and by the low draft required to use the motorization, very useful in shallow waterways.

[0007] However, despite its undeniable advantages, the long-tail motor is not without drawbacks. The thermal engine 4 of the long-tail must be out of the water and on the boat 3, to act as a counterweight and minimize the moment of inertia, thus allowing easy maneuvering of the pole 5 and the propeller 6. This thermal engine 4 is thus mounted on the turret 1 close to the user, with all the pollution and acoustic disadvantages that this implies, especially close to the navigator steering the boat.

[0008] This assembly, associated with a very long pole - at least two meters - is also essential to obtain satisfactory horizontal thrust, especially since the propeller turns around the same direction as the engine axis due to the direct transmission. This pole length makes long-tail motors extremely cumbersome, in particular when a boat has to be parked, and complicates the maneuvering of the boat during tight turns. In the absence of a gearbox at the output of the thermal engine, it is not possible to reverse with a long-tail motor.

[0009] Furthermore, since the propeller axis is not horizontal once the propeller is submerged and therefore forms an angle α with the surface of the water (see [Fig.l]), this results in a loss of thrust - since it is not entirely horizontal - and therefore poor efficiency. This efficiency is also impaired by friction between the water and the submerged pole, the length of the submerged pole being all the greater as the pole is extended when the propeller is submerged. The non-horizontality of the propeller axis and the immersion length of the pole are opposed, so that improving one of the two parameters necessarily harms the other, limiting the theoretical efficiency of long-tail engines. A toothed wheel or universal joint type transmission could be considered so that the propeller is not in the extension of the pole.However, this approach has not been satisfactory, due to the loss of efficiency associated with an additional transmission, the additional noise pollution and the sealing constraints for a submerged transmission.

[0010] Finally, long-tail engines do not allow reversing, since their thermal engine does not have a gearbox, and their engine has the same drawbacks as the thermal engines of the outboards presented above.

[0011] The invention improves the situation by proposing a device which does not have all or part of the aforementioned drawbacks. 3. Statement of the invention

[0012] To this end, the technique of the invention proposes a device of a new type, overcoming the drawbacks of conventional motorizations. This motorization device for a boat is capable of being mounted on a boat around a connecting member allowing at least two rotations in independent directions including a yaw direction of the boat. This motorization device comprises: a power module, capable of housing at least one battery; a motor unit comprising at least one electric motor electrically connected to said power module; and a bar-forming member, of elongated shape, having a proximal portion, close to the connecting member, fixed to the power module, and a distal portion, at a distance from the pivot connection, carrying the motor unit so that the motor unit is arranged at a distance from the power module; the motor unit comprising an output shaft on which at least one propeller is secured.

[0013] Thanks to this particular arrangement of the electric motor near the propeller, intended to be submerged, not only is the noise and atmospheric pollution of this motorization device drastically reduced compared to a long-tail motorization, but in addition its efficiency is improved, as is its maneuverability.

[0014] This motorization device can thus be used even with a very low draft and can be installed on any type of boat, the propulsion force being modulated by modulating the electric supply current. This radically differentiates this motorization device from outboards.

[0015] Since it is an electric motor, it is possible to reverse the polarity of the current supplying it so as to make the electric motor rotate in the opposite direction and reverse the boat, hence improving maneuverability.

[0016] This specific arrangement of the engine group near the propeller has many advantages:

[0017] - The engine / propeller transmission is direct, the transmission efficiency being in fact optimal. The device is thus lightened by a large transmission shaft, which is prone to twisting, heavy and involves high inertia. The motorization device gains in maneuverability and responsiveness.

[0018] - The engine group and the propeller are at the end of the bar and in transmission direct. This allows the engine unit and the propeller to be secured so that the propeller axis is oriented horizontally when the propeller is fully submerged. This eliminates losses due to non-horizontal propeller without the need for additional transmission.

[0019] - Since the motor unit is at least partially submerged in operation, Its cooling is ensured by the water in which it is immersed. This cooling allows a considerable lightening of the electric motor, which no longer needs to be equipped with heavy radiators (typically more than fifteen kilograms). The manufacturing cost is reduced, the handling improved and the pollution induced by the manufacture of a heavy metal radiator is avoided.

[0020] The arrangement of the power module, receiving the battery, allows it to act as a counterweight to the motor unit, further improving the maneuverability of the device. This also facilitates access to the battery for recharging or to prevent theft when the boat is at the dock.

[0021] The motorization device thus offers improved efficiency, a reduction in induced pollution, increased maneuverability and ease of use compared to all known solutions.

[0022] According to a particular aspect, the bar-forming member comprises a so-called oblique section, arranged between the two distal and proximal portions, extending in a longitudinal direction forming an angle of at least 30° with the axis of the propeller.

[0023] Thus, thanks to the oblique section, the size of the motorization device is drastically reduced. This geometry allows the motor unit and the propeller to be submerged much closer to the boat than in the case of a long-tail motorization with a straight pole. It is thus possible to take tight turns in narrow waterways with low draft.

[0024] Furthermore, this simplifies the storage of the motorization device when the boat is stopped, since it is shorter, by pivoting it to house the electric motor, the propeller and the tiller member entirely in a small boat. Once stored, the motorization device no longer protrudes, or only marginally, unlike a conventional long-tail motorization.

[0025] In addition to reducing the size, this obliqueness allows the tiller member to enter the water at a much greater angle when the propeller is fully submerged than for a conventional long-tail motor. This angle of entry into the water limits the length of the submerged tiller member and therefore the friction when the boat is propelled.

[0026] Thanks to an oblicity of at least 30° between the propeller axis and the longitudinal direction of the oblique section, the gain in compactness is more than 50% in length reduction, and reaches 65% length reduction for an angle of approximately 60° (approximately 1.15 m in length compared to 3.40 m for a conventional long-tail motorization).

[0027] According to a particular aspect, the bar-forming member comprises a so-called oblique section, arranged between the two distal and proximal portions, extending in a longitudinal direction forming an angle of at most 60° with the axis of the helix.

[0028] Limiting the angle of obliquity to 60° or less makes it possible to limit the effect of an impact of the submerged part of the motorization device with an obstacle. Indeed, in the event of contact with an obstacle (for example a shoal or a floating object), a vertical (90°) or insufficiently oblique (for example 70°) section would be equivalent to a quasi-frontal impact of the obstacle on the distal portion of the bar-forming member and the propeller. On the other hand, an obliquity of less than 60° makes it possible to deflect the impact. Furthermore, an angle of less than 60° makes it possible to obtain sufficient leverage to pivot the motorization device in the pitching direction with reduced movement on the part of the operator, in particular to bring the propeller out of the water without part of the motorization device coming into contact with the boat.This reduction in stroke for good maneuvering of the device thus allows the compatibility of the motorization device with a large number of boats.

[0029] The bar-forming member may have at least over part of its length a cross-section whose thickness transversely to the helix axis is at least three times smaller than the width.

[0030] Thanks to this refined section of the bar-forming member, it generates considerably less friction once immersed, improving the efficiency and discretion of the motorization device.

[0031] Furthermore, thanks to this particular geometry, the bar-forming member can act as a rudder for the boat. The motorization device thus plays a dual role for the boat. With this rudder function, the motorization device allows the boat to be maneuvered even with a stationary electric motor, so that it can turn or brake completely silently.

[0032] The bar-forming member may have a hydrodynamic profile.

[0033] Thanks to this hydrodynamic profile, also called hydrofoil profile, the friction of the submerged part of the device is considerably reduced, improving the efficiency. It should be noted that the hydrodynamic profile can be combined with the thickness / width ratio described above to further improve the efficiency and maneuverability.

[0034] The motorization device may further comprise at least one attitude stabilizer secured to the distal portion, close to the propeller.

[0035] The trim stabilizer improves the handling and stability of the motorization device, and in particular makes it possible to keep the propeller horizontal when it propels the boat. This trim stabilizer may, for example, comprise one or more lateral fins.

[0036] The motorization device may further comprise a protection member arranged under the propeller.

[0037] The protective member makes it possible to protect the propeller from an impact with a shoal or debris. This protective member may for example comprise a lower fin secured or in one piece with the bar-forming member, and extending at least partly under the propeller.

[0038] The motorization device may further comprise a drawbar, fixed to the power module or to the proximal portion of the bar-forming member, the drawbar being bent and / or retractable.

[0039] This tiller allows the motorization device to be easily maneuvered. Its retractable nature facilitates the storage of the motorization device. Its elbow provides a better angular travel of the motorization device.

[0040] The bar member may be made of stainless steel or aluminum.

[0041] The bar-forming member thus plays the role of a heat sink, thanks to the properties of aluminum. It is thus possible to connect this bar-forming member to parts likely to release heat, for example a power module controller, with a thermally conductive material (for example thermal paste). The member, thanks to its large size, thus maintains a relatively low touch temperature, limiting the risk of burns.

[0042] The at least one battery that can be housed in the power supply module can be removable. This simplifies the transport of the device, as well as its recharging, the battery being able to represent between a quarter and three quarters of the mass of the entire motorization device. 4. List of Figures

[0043] The proposed technique, as well as the various advantages that it presents, will be more easily understood, in the light of the description which follows of illustrative and non-limiting embodiments thereof, and of the appended drawings among which: - [Fig.l] represents a classic long-tail motorization; - [Fig.2] represents a schematic diagram of an example of a motorcycle device rization according to the invention; - [Fig.3] represents a detailed view of the device of [Fig.2], seen from the side; - [Fig.4] represents a top view of the device of [Fig.3]; - [Fig.5] represents a perspective view of a prototype of the device of the [Fig.3] ; - [Fig.6] represents a perspective view from above of the device of [Fig.5] - [Fig.7] represents a perspective view of the profile of the device of [Fig.5]; - [Fig.8] represents a perspective view of the propulsion group of the device of [Fig.5], seen from the rear; - [Fig.9] represents a perspective view of the propulsion group of the [Fig.8], three-quarter view; - [Fig. 10] represents a perspective view of the device of [Fig.5] mounted on a boat; - [Fig.l 1] represents a view of the front face of the power supply module of the device of [Fig.5]; - [Fig. 12] represents a first variant of the device of [Fig.3]; - [Fig. 13] represents a second variant of the device of [Fig.3]; - [Fig. 14] represents a third variant of the device of [Fig.3]. 5. Detailed description of the invention

[0044] Various embodiments of the proposed technique are illustrated below, treated as simple illustrative, and non-limiting, examples, with reference to Figures 2 to 14. 5.1. General principle

[0045] The starting point of the invention is a long-tail motorization as described above. From this basis, the general principle of the invention is to radically modify the arrangement of its constituent elements. Thus, on the one hand the motor group comprises an electric motor and not a thermal engine. On the other hand, the motor group is offset at the end of the pole, the propeller being at the direct output of the motor group.

[0046] The direct proximity between the engine group and the propeller, at the end of the pole, has many advantages. The engine is submerged when the propeller propels the boat. The water, especially when moving relative to the engine group, therefore cools the engine group entirely passively. The design of the engine group is simplified and lightened, because there is no longer any need to install heavy radiators to evacuate the heat that the engine produces during operation.

[0047] Furthermore, since the propeller is a direct output from the engine group, the transmission is radically lightened, since there is no longer any need for an elongated shaft, housed in a pole or forming it. The efficiency is improved. But, in addition to the gain in efficiency, this removes all the constraints of pole geometry of conventional long-tail engines, as will be seen below. Indeed, the propeller being a direct output from the engine group, it forms with said engine group an integral propulsion group whose arrangement, in particular the orientation, are much more modular than for a conventional long-tail engine, while being of simpler design.

[0048] Other advantages of this new type of arrangement of the constituent elements of the motorization device according to the invention will be developed below.

[0049] Reference is made to Figures 2 to 11.

[0050] The boat 3 defines an orthogonal reference frame formed by a roll direction X, a pitch direction Y and yaw direction Z.

[0051] The motorization device according to the invention, hereinafter referred to as device 10, is capable of being mounted on a boat 3. The mounting is done by a connecting member 12 allowing at least two rotations in two independent directions, at least one of which is the direction z coinciding with the yaw direction of the boat Z. The connecting member 12 can be synthesized in the form of a ball joint with finger when the connecting member only allows two rotations, as shown diagrammatically [Fig.2].

[0052] The device 10 comprises a power supply module 14, a motor group 16, a propeller 18 and a bar 20. The power supply module 14 is capable of receiving a battery to power the device 10.

[0053] In the illustrated example, the power supply module 14 receives the battery 140 in an open housing. The power supply module 14 may further comprise a controller 142, arranged to electrically control the motor group 16.

[0054] The controller 142 may further comprise an on / off switch 1420, a display screen 1422, a power-on indicator light 1424, a circuit breaker and / or associated connectors 1426, as can be seen in the illustrated example [Fig. 11]. The connectors 1426 make it possible to electrically connect the battery 140 to the controller 142. Here, the connectors 1426 are visible, i.e. visible from the outside. Alternatively, it could be housed in the device, for example to protect it from external moisture.

[0055] In the example visible in particular in figures 5 to 7 and 11, the controller is housed under the battery 140. Other arrangements are of course possible, typically depending on the degree of miniaturization of the controller 142. The power supply module thus comprises a housing 144 forming the housing of the battery 140 and, where appropriate, and the housing of the controller 142.

[0056] The controller 142 could, as a variant (not shown in the figures), be arranged in a housing separate from the power supply module 14, and connected to the latter by an electrical cable.

[0057] The motor group 16 is arranged at a distance from the power module 14. The motor group 16 comprises an electric motor 160. This electric motor 160 is electrically connected to the power module 14. The motor group 16 comprises an output shaft 162 on which the propeller 18 is secured. The output shaft 162 defines a propeller axis U.

[0058] In more sophisticated variants, several propellers may, as a variant, be mounted on the output shaft of the motor group 16. Still as a variant, the motor group 16 comprises several output shafts on which one or more propellers are mounted.

[0059] The bar 20 is of elongated shape, and rigid. The bar 20 has a portion proximal 22 and a distal portion 24, respectively close to the connecting member 12 and at a distance from the connecting member 12. The power supply module 14 is secured to the proximal portion 22. The motor group 16 is secured to the end portion 24.

[0060] The motor group 16 is thus arranged at a distance from the power supply module 14. The motor group 16 has the function of driving the propeller 18 in rotation, so as to propel the boat 3.

[0061] From the particular arrangement described above, it is understood that the motor unit 16 is in the immediate vicinity of the propeller 18 and is intended to be at least partly immersed in the water when the propeller 18 is itself immersed in the water to play its propulsion role.

[0062] Thanks to this new type of arrangement, the electric motor 160, and more generally the motor group 16, are immersed, which allows them to be cooled by the surrounding water. This cooling makes it possible to do without the heavy radiators usually used in cooling electric motors.

[0063] The device 10 thus defines a reference frame of its own, formed of three directions x, y and z. The z direction coincides with the yaw direction Z of the boat. The y direction is the other of the two pivot directions of the connecting member 12. The x direction is a third direction making it possible to define a reference frame.

[0064] In the example described here, and for the sake of brevity, the (x, y, z) reference frame is an orthogonal reference frame and coincides with the (X, Y, Z) reference frame of the boat when the device is oriented in alignment with the boat, i.e. the propeller 18 is neither oriented to port nor oriented to starboard. By convention, the z (yaw) direction is oriented upwards when the boat is floating. By convention again, the X direction corresponds to the U direction of the propeller axis.

[0065] In fact, this reference (X, Y, Z) makes it possible to define the top and bottom of the motorization device 10 (in the Z direction), port and starboard of the motorization device 10 (in the Y direction) and a front and a rear of the motorization device 10 (in the X direction), corresponding to these same directions (top, bottom, port, starboard, front, rear) of the boat 3.

[0066] The power supply module 14 is capable of housing a battery 140 for powering the motorization device. This battery 140, removable or not, will be described below.

[0067] The motor group 16 may comprise, in addition to the motor 160, a geared motor making it possible to adjust the torque or the rotation speed at the motor output. The motor group 16 is preferably waterproof, at least for its electrical part, so that it can be submerged. The motor group may be entirely waterproof, including any geared motor or any other part whose exposure to water would be detrimental. The motor group 16 may also be faired, so as to limit the friction when immersed.

[0068] The bar 20 is, by definition, of elongated and rigid shape. Its role is to connect the propulsion group 28 formed by the engine group 16 and the propeller 18 to the connecting member 12, so that a pivoting of the bar 20 around one of them causes a movement of the propeller and the engine to port or starboard (around the z direction), or upwards or downwards (around the y direction).

[0069] The bar 20, as well as the fixed parts secured to the bar 20 including the housing 144 of the power supply module 14, together form the chassis 50 of the motorization device 10.

[0070] The pivoting of the device 10 around the rotations permitted by the connecting member 12 can be done directly, for example by an operator who would “force” the movement of the bar 20 manually. As a variant, shown in Figures 2 to 7, the motorization device 10 comprises a rudder member 26 by means of which the operator pivots the entire motorization device 10. This rudder member 26 can for example be a tiller, also called a tiller.

[0071] The tiller 26 can be retractable, foldable and / or removable, so as to facilitate its storage. Here, the tiller 26 is arranged in the extension of the power supply box 14. The tiller 26 can be bent and / or oriented upwards (in the z direction, therefore). In the example visible in Figures 5 to 7, the tiller 26 is bent in the y direction (to starboard), but not in the z direction (upwards). This bend makes it possible to orient the tiller 26 towards the outside of the edge of the boat. Gripping the tiller 26 is made easier, and above all it provides the motorization device 10 with greater vertical travel to surface the propeller 18 and the motor unit 16. In other words, this allows a greater angular amplitude before the power module 14 or the tiller 26 comes into abutment against one of the parts of the boat (bottom, crosspiece, side, etc.).

[0072] As is apparent in Figures 4 and 6, the example of a motorization device illustrated there is, with a few exceptions such as the drawbar 26, substantially symmetrical with respect to the plane (x, z).

[0073] In continuous operation, the motorization device 10 releases heat in three locations: the electric motor 160, the controller 142, when there is one, and to a lesser extent the battery 140.

[0074] In addition to immersion cooling, the motor unit 16 may be cooled by relative wind when the motor unit is partially or completely out of the water. Since the air around the water is slightly cooler than that at the electrical box, this allows cooler air to be enjoyed.

[0075] The controller 142 is cooled primarily by the relative wind when the boat 3 is propelled. To improve this cooling, the chassis 50 of the motorization device 10, in particular the housing 144 of the power supply module 14 and the bar 20, can be made of a thermally conductive material, in particular a metal. In such a case, the controller is linked to this chassis 50 by thermal paste.

[0076] The chassis 50 may for example be made of aluminum, or alternatively of stainless steel. 6061 aluminum is a suitable material for making this chassis, due to its mechanical strength and its thermal conductivity of 170 W / mK. 6061 aluminum has good resistance to corrosion, including in a marine environment. This conductive metal chassis may also have a surface treatment of the anodizing or electrophoresis type. The chassis 50 may comprise several materials depending on the part, for example stainless steel for the housing 144 and aluminum for the bar 20.

[0077] Due to its large dimensions (compared to the rest of the elements of the motorization device 10), the chassis 50 made of thermally conductive material can act as a heat sink for the controller 142, both for its submerged part cooled by the surrounding water and for its emerged part cooled by the air or the relative wind. In addition, since the chassis is large, it has a large heat capacity, and therefore remains warm when the motorization device is in operation, where the controller 142 can be significantly hotter. This makes it possible to limit the risks of burning upon contact with the motorization device. This also improves the heat dissipation of the motor 160.

[0078] In the tests carried out by the inventors, the motorization device operates normally up to a motor temperature of approximately 65°C. The controller 142 can integrate a thermal probe (not visible in the figures) making it possible to implement a reduction in the supply current of the electric motor if the temperature exceeds a certain threshold, whether due to an external reason or an internal anomaly. The thermal management of the battery can also follow a similar logic, thanks to a battery management system, also called BMS (battery management system). It is thus possible to protect the electric motor and / or the battery from overheating. 5.2. Connecting body

[0079] In the example shown in Figures 5 to 7 and in particular [Fig.7], the connecting member 12 comprises a first pivot 120 around the direction z and a second pivot 122 around the other direction of rotation permitted by the connecting member 12. As expressed above, this other direction of rotation preferably corresponds to the direction Y, which simplifies navigation since the motorization device 10 can pivot in the yaw direction Z and in the pitch direction y (relative to the motorization device). Nothing prevents this other direction from being non-orthogonal to the yaw direction Z.

[0080] In the example described here, see [Fig.7], the connecting member 12 operates in tandem with a plate 124, visible [Fig. 10], to form the first pivot 120. The connecting member 12 comprises a sleeve 126, of generally cylindrical shape. The plate 124 is designed to be fixed on all possible boats and provide a cylindrical housing, of a shape complementary to that of the sleeve 126. When the plate 124 is fixed on a boat 3, the axis of symmetry of the cylindrical housing is substantially parallel to the yaw direction Z. The cooperation of shape of the sleeve 126 and the cylindrical housing makes it possible to obtain the first pivot 120.

[0081] In the example visible in [Fig.10], this plate 124 is fixed — removably or not — to a crossbar 30 of a boat 3. Here, the crossbar 30 extends in the Y direction, i.e. the pitch axis. This assembly would naturally work with a crossbar 30 in the roll axis X of the boat 3, and more generally any direction of the crossbar as long as the cylindrical housing is vertical (in the Z direction) once the plate 124 is fixed.

[0082] When fixed on the boat, the plate 124 rests against the crosspiece 30 by means of an upper surface 1240. One or more nuts 1242 secure the plate 124 on the crosspiece 30, for example by tightening. This plate 124 thus makes it possible to fix the motorization device 10 to a huge variety of boats, in particular traditional boats from Southeast Asia.

[0083] Other plate attachment systems 124 may be envisaged, making it possible to vary the shape of the plate according to the nature of the boat. Other variants of the first pivot 120 may be envisaged, for example with a plate directly integrated into the motorization device 10 and a different first pivot 120, for example with ball bearings or bushings.

[0084] The second pivot 122 may comprise, as can be seen for example [Fig.7], a stop 1220. This stop 1220 comprises a surface 1222 against which a wall 1224 of the chassis 100 of the motorization device 10 (here, a lower wall 1224 of the housing 144 of the power supply module 14) comes into contact when the motorization device 10 is in the so-called horizontal rest position. In this horizontal rest position, the engine group 16 is stopped, and the propeller 18 is submerged, and its propeller axis leans very slightly below the horizontal, that is to say that the propeller axis U is almost but not totally oriented in the Y direction. In such a situation, the weight of the bar 20 and of the propulsion assembly 28 hold the wall 1224 against the surface 1222 of the stop 1220.

[0085] This stop 1220 allows the entire motorization device 10 to remain in this horizontal rest position without rubbing on the rear of the boat 3 when the motorization device 10 is stopped and the lateral fins 40 forming the trim stabilizer are therefore inoperative (since there is little or no propulsion). When the propeller 18 is driven and propels the boat 3, the latter lifts slightly management of its horizontal rest position and stabilizes horizontally (i.e. propeller axis thanks to the lateral fins forming the attitude stabilizer.

[0086] In the example of [Fig.7], this stop 1220 here comprises an arm, finger or oblique cleat in the plane (X, Z) playing a role similar to that of a strut in carpentry. Other alternatives for forming the stop 1220 are of course conceivable.

[0087] Thus, the stop 1220 and the trim stabilizer cooperate to keep the propeller axis substantially horizontal over the entire range of propulsion speeds, avoiding any friction or impact with the hull of the boat 3.

[0088] The second pivot may optionally comprise rotation-enhancing parts, for example a ball bearing or a bushing. The second pivot 122 may optionally still comprise a rotation lock in the y direction by clamping or by an elastic element such as a spring. 5.3. Battery

[0089] The battery 140 is, in the example visible in the figures, removable and visible, that is to say accessible from the outside of the motorization device 10. The battery 140 is here preferably waterproof, or at least splash-proof, as is its electrical connection with the rest of the power supply module 14. Alternatively, the power supply module 14 may comprise a housing having a closed housing, and the battery 140 is then received in this closed housing, this closed housing of the housing protecting the battery from water. The two options (waterproof battery and closed waterproof housing) are obviously cumulative.

[0090] The battery 140 can be formed in two parts, so as to distribute the weight between port and starboard. Alternatively, it is possible to envisage several separate batteries which can be housed simultaneously in the power module 14.

[0091] A battery management system (BMS) has been mentioned above. The battery management system, in addition to the overheating protection described above, also makes it possible to implement an energy-saving mode, in which the motor supply current is reduced according to the remaining battery capacity. The activation of this energy-saving mode may, for example, depend on the battery output voltage, which decreases as the battery capacity decreases. The propulsion speed of the boat is reduced, for example to 4 km / h, compared to 10 to 20 km / h at cruising speed. This makes it possible to multiply the range in kilometers of the motorization device by at least three times, or even up to ten times.

[0092] The inventors have produced three prototypes of motorization devices, suitable for motorizing a 500 kg boat. In these prototypes, the battery has a capacity of 800, 2000 and 3300 Wh, respectively. The weight of the battery is then of approximately 4, 13 and 19 kg, respectively, and the autonomy of these prototypes is respectively approximately 1h at 10 km / h (or 30 km at 4 km / h), 1h at 15 km / h (or 80 km at 4 km / h) and 1h at 18 km / h (or more than 120 km at 4 km / h). These values ​​concern prototypes, and are in no way limiting, the battery can have a wide range of capacities and weights. In large and high-power models, the motorization device can propel a boat weighing several tons.

[0093] The weight of the battery makes it possible to act as a counterweight with the motor unit located at the end of the bar 20. To improve this counterweight role, the battery 140 is arranged so that its center of gravity is located slightly to the front relative to the pivot in the Y direction. This weight counterbalances that of the electric motor, without the overall size of the motorization device 10 being any greater.

[0094] The electric motor may have a continuous power of 1 to 6 kW, with a peak power (over short periods) of 15 kW. For a very powerful version of the motorization device 10, for example with a motor of more than 10 kW, the power module may optionally comprise aluminum fins, for example arranged under the housing of the power module 14, to increase the heat dissipation thereof. It is also possible, to achieve high propulsion powers, to couple two motorization devices side by side. 5.4. Ailerons

[0095] Near the propulsion group 28, the motorization device 10 may comprise one or more fins, integral with the chassis 28.

[0096] The motorization device may in particular comprise a pair of lateral fins 40. These lateral fins 40 are arranged on either side of the propulsion unit 28. Here, the lateral fins extend in the plane (X, Y). The lateral fins 40 are secured to the bar 20. In the example visible in particular figures 8 and 9, the fins are fixed by screwing to the engine unit 16. Alternatively, the lateral fins 40 may be secured directly to the bar 20, for example by welding.

[0097] The lateral fins 40 act as a pitch stabilizer. In addition, the lateral fins 40 protect the propeller 18 laterally from debris or obstacles. The pair of lateral fins 40 could be replaced by a single fin covering both sides of the propeller.

[0098] Near the propulsion group, i.e. the engine group 16 and the propeller 18, it may further comprise a lower fin 42. The lower fin 42 is arranged under the propulsion group 28, in particular under the propeller 18.

[0099] In the example visible in [Fig.7], the lower fin 42 is formed by the end of the bar 20, in the extension thereof. This single-piece design simplifies the manufacture of the bar / lower fin assembly. Alternatively, the lower fin 42 could be a separate part, secured to the bar 20 for example by welding, screwing, gluing, etc.

[0100] The lower fin 42 forms a protective member for the propulsion group 28, in particular in the event of an encounter with debris or a shoal.

[0101] The fins are here plate-shaped, and made of a rigid material, for example the same as that of the bar. The lateral fins 40 and the lower fin 42 here have constant thicknesses. They may alternatively have an optimized profile to reduce friction, for example a hydrofoil profile. 5.5. Bar geometry

[0102] In one embodiment, the bar 20 comprises an oblique section 200, arranged between the two proximal 22 and distal 24 portions. This oblique section 200 extends in a longitudinal direction V forming an angle between 30 and 60° with the direction U, that is to say the axis of the helix 18, as can be seen in particular in [Fig.3].

[0103] The geometry of the bar 20 with this oblique section 200 makes it possible to drastically reduce the size of the motorization device 10. This makes it possible in particular to immerse the propulsion group 28 much closer to the boat than in the case of a long-tail motorization.

[0104] The length of the motorization device is thus very reduced — 1.30 m for an oblicity of 45°, and 1.15 m for an oblicity of 60°, whereas long-tail motorizations have a length of more than 3.40 m. This geometry of the bar 20 makes it possible to take tight turns in narrow waterways with low draft. The motorization device thus described has a size comparable to that of an electric outboard motor of the same power, but is significantly lighter. For example, with an 800 Wh battery, the device weighs approximately 12 kg, including 4 kg of battery. With a 1000 Wh version, the device weighs approximately 13 kg.

[0105] This reduced size also makes it possible, when the boat is stopped, to store the motorization device 10 in the boat, by pivoting it to house the electric motor, the propeller and the tiller-forming member in its entirety in a small boat. Parking small boats is simplified since the motorization device no longer protrudes from it.

[0106] The advantages of the oblique section geometry do not stop at the gains linked to reduced bulk: since the oblique section is, as its name indicates, oblique relative to the propeller axis, this oblique section enters the water at a much greater angle when the propeller is fully submerged. This angle of penetration into the water, much greater than that of a pole of a long-tail motor, limits the length of the submerged bar-forming member and therefore the friction when the boat is propelled.

[0107] The range between 30 and 60° has several advantages.

[0108] Angles of less than 30° between the propeller axis 162 and the longitudinal direction V of the oblique section 200 do not allow for a gain in compactness and satisfactory efficiency at the bar level, in particular for storing the motorization device when stationary in small boats, for the length of submerged pole or for maneuverability in turns.

[0109] The inventors have further observed that angles greater than 60° should be avoided if possible, because, in the event of contact with an obstacle (for example a shoal or a floating object), a vertical (90°) or insufficiently oblique (for example 70°) section would be equivalent to a quasi-frontal impact of the obstacle on the distal portion 24 of the bar 20 and the propeller 18, possibly on the lower fin 42. On the contrary, with an oblique section angle 200 whose angle with the propeller axis is less than 60°, for example equal to 45°, this angle makes it possible in practice to deflect the impact. This is similar to the armor of a tank or a ship, which is less affected by a shell impact when it has an oblique side.

[0110] Furthermore, angles greater than 60° generally lead to angular travel problems, because the angular travel required to bring the propeller to the surface is all the greater as the angle is close to 90°, while the angular range available to actually pivot the motorization device once installed on the boat is limited by the geometry of the boat. This could cause the device to come into contact with the boat, for example its bottom, its bench, a transom, etc., before the propeller is completely out of the water, preventing good navigation. In other words, the maneuverability of the motorization device 10 comes in particular from the leverage effect that the geometry with an angle (U, V) less than 60° allows (including for small angles, around 30°).

[0111] The inventors have found that this oblique geometry of the bar 20 makes it possible, combined with the attitude stabilizer described above, to obtain a dynamic balance of the propulsion. In other words, the combination of these two aspects makes it possible to obtain propulsion that can be freely oriented or surfaced without having to exert any effort to maintain it by default in its horizontal attitude of optimal thrust.

[0112] The bar 20 preferably has a refined profile in the y direction, so as to reduce friction with the water. More precisely, the bar 20 has a thickness e (visible [Fig.8]) in the y direction at least three times smaller than its width L (visible [Fig.7]). In the example illustrated in Figures 5 to 7, the ratio L / e is approximately 8.

[0113] Thanks to this refined geometry of the bar, the bar generates considerably less friction once immersed, improving the efficiency and discretion of the motorization device.

[0114] Furthermore, thanks to this refined geometry, the bar 20 can act as a rudder for the boat 3. The motorization device thus offers an additional function, in addition to its motorization. With this rudder function, the motorization device 10 also allows maneuvering of the boat even with a stationary electric motor, so as to be able to turn or brake in a completely silent manner.

[0115] The bar 20 may also have a hydrodynamic profile, also called a hydrofoil profile. A NACA 0012 type hydrodynamic profile has given satisfaction to the inventors for the production of prototypes, in particular for its properties of penetration into water, laminar flow and absence of vortex which would generate cavitation in the propeller. Other hydrodynamic profiles having similar properties could be envisaged. The bar 20 may also have a hollow profile, so as to house inside it electrical cables electrically connecting the motor unit 16 to the power module 14. This also lightens the bar 20.

[0116] This geometry with a refined and / or hydrodynamic profile is made possible by moving the electric motor close to the propeller.

[0117] The hydrodynamic profile thus described makes it possible to greatly reduce the cavitation phenomenon that would be found on a cylindrical bar beyond 6-7 knots. It is thus possible to propel the boat at high speeds, beyond 15 knots. The hydrodynamic profile also makes it possible to improve the rudder function described above. 5.6. Bar Variants

[0118] In an example shown [Fig.12], the bar 20 is formed from a pole 300 at the end of which the propulsion group 28 is fixed. The pole is here conventionally cylindrical, but can alternatively adopt a hydrofoil profile.

[0119] The pole 300 may be hollow, making it lighter. In such a case, the cables used to electrically connect the power supply module 14 to the motor group 16 may be housed in the pole 300, so as to protect them from water.

[0120] The propulsion group 28 can be fixed to the pole 300 so that the axis U' of the propeller forms a non-zero angle with the longitudinal direction V'. This angle can be at least 3° for a straight pole as in this example of [Fig. 12]. This arrangement, made possible by the attachment of the propeller 18 to the output axis of the engine group 16, allows the horizontality of the propeller 18 once submerged, eliminating the losses of horizontality of conventional long-tail thermal engines. The efficiency is improved.

[0121] It is of course possible that this angle between the pole 300 and the propeller axis could be 30°, or even 40° or more. In such a case, the pole 300 forms the oblique section described above.

[0122] Reference is made to Figures 13 and 14.

[0123] In these two figures, the bar is a pole 400 having an elbow 410. The pole 400 thus has a proximal pole portion 420, comprising the proximal portion described above (i.e. to which the power supply module 14 is attached) and a distal pole portion 430, comprising the distal portion described above (to which the motor group 16 is attached).

[0124] The distal portion of pole 430, intended to be submerged so that the propeller 18 can propel the boat, thus forms the oblique section described above.

[0125] The bent pole 400 may also be hollow, and possibly house the cables connecting the power supply module 14 and the motor unit 16. The bent pole 400 may be of cylindrical section, or have a different profile, for example hydrodynamic to reduce friction once submerged and play the role of a rudder, as explained above.

[0126] In the example of [Fig. 13], the proximal pole portion 420 is horizontal (i.e., extends in the x direction) and the distal pole portion 430 is bent at approximately 45° relative to the proximal pole portion 420. In the example of [Fig. 14], the proximal pole portion 420 forms an angle of 5° with the y direction and the distal pole portion 430 is bent at approximately 50° relative to the proximal pole portion 420. Thus, when the propeller 18 is submerged to propel the boat, the distal pole portion 430 forms an angle of approximately 45° with the water, in both cases.

[0127] This bar shape, with a 400 bent pole, makes it possible to simplify its manufacture. It is thus possible to start from a standard, cylindrical pole and bend it using standard metallurgy techniques. This bent geometry is made possible by moving the electric motor close to the propeller.

[0128] An electric motorization device has thus been seen, the size, efficiency, maneuverability and ecological character of which are drastically improved compared to the state of the art.

[0129] The improvements described above, however, make it possible to propose a variant of the motorization device, capable of being mounted on a boat via a connecting member as described above. In such a case, the motorization device comprises a power module, capable of housing at least one energy reservoir (for example a battery or gasoline tank), a motor unit comprising at least one motor connected to the energy reservoir, and a bar-forming member of elongated shape. The bar-forming member has a proximal portion, close to the connecting member, and fixed to the power module, and a distal portion, at a distance from the pivot connection, carrying a propeller secured to an output shaft of the motor unit, so as to be able to be driven in rotation by the motor. The bar-forming member comprises a section oblique, arranged between the two distal and proximal portions, extending in a longitudinal direction forming an angle of at least 30° with the axis of the helix.

[0130] This oblique section makes it possible to obtain the same advantages as those of the oblique section geometry described above, namely reduced friction (since less submerged length), improved maneuverability, a reduction in the length of the device and an absence of losses linked to the non-horizontality of the propeller. Such a configuration of the motorization device also allows the bar-forming member to act as a rudder, depending on its geometry.

[0131] To ensure transmission and non-horizontality, the motor unit may be arranged at the distal portion of the bar-forming member—similar to what is described above for the electric motor. Alternatively, the motor unit may be fixed at another location on the motorization device. For example, the motor unit may be arranged at a location on the motorization device that is not intended to be submerged, such as near the power module. In the latter case, it may be necessary to obtain a non-zero motor axis / propeller axis angle, and the transmission may then comprise a universal joint or a bevel gear for this purpose. The motor unit may alternatively be offset upwards along the z axis, and the transmission with the propeller may be achieved by a set of gears, a belt, a chain, or any other suitable solution for transmitting forces at the output of the motor unit.

Claims

Claims

1. Motorization device (10) for a boat (3), capable of being mounted on a boat (3) around a connecting member (12) allowing at least two rotations in independent directions including a yaw direction (Z) of the boat (3), the motorization device comprising: - a power supply module (14), capable of housing at least one battery (140); - a motor unit (16) comprising at least one electric motor (160) electrically connected to said power supply module (14); and - a bar-forming member (20, 300, 400), of elongated shape, having a proximal portion (22), close to the connecting member (12), fixed to the power module (14), and a distal portion (24), at a distance from the pivot connection (12), carrying the motor group (16) so that the motor group (16) is arranged at a distance from the power module (14); the motor group (16) comprising an output shaft (162) on which at least one propeller (18) is secured.

2. Motorization device according to claim 1, in which the bar-forming member (20, 300, 400) comprises a so-called oblique section (100, 200, 300, 430), arranged between the two distal and proximal portions, extending in a longitudinal direction (V, V') forming an angle of at least 30° with the axis of the propeller (U).

3. 3. Motorization device according to one of the preceding claims, in which the bar-forming member (20, 300, 400) comprises a so-called oblique section (100, 200, 300, 430), arranged between the two distal and proximal portions, extending in a longitudinal direction (V, V') forming an angle of at most 60° with the axis of the propeller (U).

4. Motorization device according to one of the preceding claims, in which the bar-forming member has (20, 300, 400) at least over part of its length a cross-section whose thickness (e) transversely to the propeller axis is at least three times smaller than the width (L).

5. Motorization device according to one of the preceding claims, in which the bar-forming member (20, 300, 400) has a hydrodynamic profile.

6. Motorization device according to one of the preceding claims, further comprising at least one attitude stabilizer (40) secured to the distal portion, near the propeller (18).

7. Motorization device according to one of the preceding claims, further comprising a protection member (42) arranged under the propeller (18).

8. Motorization device according to one of the preceding claims, further comprising a drawbar (26), fixed to the power module (14) or to the proximal portion (22) of the bar-forming member (20, 300, 400), the drawbar (26) being bent and / or retractable.

9. A motorization device according to one of the preceding claims, wherein the bar-forming member (20, 300, 400) is made of stainless steel or aluminum.

10. 0 Motorization device according to one of the preceding claims, in which the at least one battery (140) which can be housed in the power supply module is removable.

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