An electric drive system for a ship, such as a surfboard or a paddleboard, equipped with a cooling means

Abstract

The present invention relates to a motorization system for a watercraft with electric assistance intended to carry a user on water, the invention being used in particular in the field of surfboards, paddleboards or windsurfing boards, as well as in the field of kayaks or canoes. The motorization system is adapted to be connected to a source of electric energy and comprises, on the one hand, a watertight enclosure (1) intended to be integrated in or on the hull of a watercraft, in which a rotor (2) and a stator (3, 7) are arranged, and, on the other hand, a shaft (4) connected at a first end to the rotor (2) and projecting in a watertight manner outside the enclosure (1) by a second end opposite the first end. At its second end, the shaft (4) can be connected to a propulsion means of the watercraft, such as a propeller, and when the system is supplied with electric energy, the rotor (2) rotates and drives the shaft (4) with this rotation. The system also comprises cooling means (5), which itself comprises at least one first elongated assembly (5) at least partially made of metal, a first end of which is arranged inside the enclosure (1) and which protrudes in a watertight manner outside the enclosure (1) at a second end opposite the first end, allowing the conduction of heat from the inside to the outside of the enclosure (1) along the first elongated assembly (5).

Description

Technical Field

[0001] The present invention relates to a power system for a motor-assisted ship intended to carry a user on water. It finds particular application in the fields of surfboards, paddleboards, or windsurfing boards, as well as in the fields of kayaks or canoes.

Background Art

[0002] As an example, a surfboard is intended to slide a user on water under the propulsion action provided by waves. Generally, when there are no waves in a given area where the user is located, the user lying on the board uses their arms to provide the propulsion force necessary for the board to reach an area where waves are being formed or are already formed.

[0003] Another example is a paddleboard, which is intended to slide a user on water under the propulsion action of a user equipped with a paddle. Similar to the case of a surfboard, a paddleboard can also slide a user on water under the propulsion action provided by waves.

[0004] There are other examples of ships that enable a user to navigate on water by means of mechanical propulsion directly provided by the user themselves or by means such as one or more paddles or oars, and / or by propulsion provided by the environment such as wind or waves.

[0005] To facilitate the use of these ships, and in particular to facilitate propulsion in places or times where the mechanical propulsion provided by the user or the environment is insufficient, it is possible to attach to these ships an electric assist device, i.e., an electrified system that drives mechanical propulsion means such as a propeller.

[0006] Generally, marine propulsion by a propeller requires the propeller to rotate at a relatively low speed in order to avoid the cavitation phenomenon of the propeller.

[0007] Conventionally, in order to rotate a propeller, it has been possible to use two types of electric motors: an "inrunner" type motor in which the inner core rotates within a fixed outer cage, and an "outrunner" type or rotating cage type motor in which the outer cage rotates around the inner core.

[0008] "Inrunner" type motors can be cooled relatively easily because their outer part is fixed and can be brought into contact with a cooling system provided for this purpose. However, these motors generally rotate very rapidly and thus require the use of a speed reducer to avoid the cavitation phenomenon described above. This results in a loss of efficiency and an increase in mechanical complexity, and correspondingly an increase in maintenance and cost.

[0009] "Outrunner" type motors rotate more slowly than "inrunner" type motors for a given outer diameter and thus limit the cavitation phenomenon without the complexity associated with the use of a speed reducer as described in the previous paragraph. In fact, with "outrunner" type motors, it is possible to maximize the interaction diameter between the coils of the central fixed stator and the magnets of the outer rotating rotor. Thus, the use of an "outrunner" type motor within a watertight enclosure makes it possible to obtain a propeller that rotates more slowly without using a speed reducer. However, unlike "inrunner" type motors, these "outrunner" type motors are difficult to cool because their outer part rotates and thus cannot be brought into contact with a conventional cooling system such as a cold wall.

[0010] Conventional solutions for cooling "outrunner" type motors, such as the use of water circulation within the fixed part of the motor, are not satisfactory. In fact, they require the presence of pipes inside the motor, water inlets and outlets, which makes implementation complex. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] Accordingly, one of the objectives of the present invention is to particularly solve the above-mentioned problems. Accordingly, the objective of the present invention is to propose, in particular, an electrification system for a ship, such as a surfboard or a paddleboard, configured to be connected to an electrical energy source.

Means for Solving the Problems

[0012] This system comprises a watertight enclosure intended to be incorporated within or on the hull of the ship, and within the enclosure are arranged a rotor and a stator, and a shaft connected to the rotor by a first end and protruding watertightly outside the enclosure by a second end opposite the first end.

[0013] The shaft is adapted to be connected by its second end to a means of propulsion of the ship, such as a propeller, and when electrical energy is supplied to the system, the rotor begins to rotate and drives the shaft by this rotation.

[0014] The system further comprises cooling means. These cooling means comprise at least one first elongated assembly, at least partially made of metal, and a first end of the first elongated assembly is arranged inside the enclosure. This elongated assembly protrudes watertightly outside the enclosure by a second end opposite the first end and allows the conduction of heat from the inside to the outside of the enclosure along the first elongated assembly.

[0015] According to a particular embodiment, the system also comprises one or more of the following features, either alone or in all technically possible combinations: - The first end of the first elongated assembly is fixed to the stator; - The stator comprises at least one fixing element, such as a fixing plate, and the first end of the first elongated assembly is connected to said fixing element; - The first elongated assembly comprises at least one first part, such as a rod, formed integrally with at least a part of the stator; - The first elongated assembly comprises at least one first part, such as a rod, press-fitted into a housing provided in the stator, the housing comprising a pasty heat-conductive material such as heat-conductive silicone; - At least the first part of the first elongated assembly is a rod having a substantially circular cross-section; - The first elongated assembly is a rod having a circular cross-section that protrudes from the enclosure in a watertight manner by means of an O-ring; - The system comprises an electronic control unit fixed to the stator and configured to control the operation and power supply of the system, and forms a heat path between the control unit and the first elongated assembly to enable heat released by the control unit to be conducted outside the enclosure along the heat path and the first elongated assembly; - The system comprises an electronic control unit arranged inside the enclosure and configured to control the operation and power supply of the system, and the cooling means comprises at least one second elongated assembly that is at least partially metallic and is fixed to the control unit by a first end and protrudes in a watertight manner outside the enclosure by a second end opposite the first end, enabling heat from the control unit to be conducted outside the enclosure along the second elongated assembly; - At least a part of the second elongated assembly is a rod having a substantially circular cross-section; - The second elongated assembly is a rod having a circular cross-section that protrudes from the enclosure in a watertight manner by means of an O-ring; - The second ends of the first and / or second elongated assemblies have slats formed at intervals and parallel to the axes of the first and second elongated assemblies respectively; - The rotor comprises a rotating cage and the stator comprises a fixed core arranged inside the cage.

[0016] According to a second aspect, the present invention also relates to a watercraft, such as a surfboard or a paddleboard, with electric assistance, comprising propulsion means enabling the watercraft to move on water or underwater, and an electric energy source.

[0017] The watercraft further comprises the above-described electrification system, the watertight enclosure of the electrification system being integrated on or within the watercraft, the shaft of which is connected to the propulsion means by a second end, enabling the driving of the propulsion means when electrical energy is supplied to the electrification system by a power source and the cooling of the electrification system by heat exchange between the second end of the first elongated assembly and the surrounding water.

[0018] Thus, the powering system of the present invention makes it possible to obtain a watercraft with electric assistance that does not require propulsion forces for complex and expensive mechanical parts that require special maintenance, such as a reduction gear, or complex cooling means that are also expensive and require special maintenance.

[0019] In fact, in the system of the present invention, heat is discharged along a heat path guided by the elongated assembly. This heat path leads from the inside to the outside of the motor's watertight enclosure, where the heat is released into the surrounding water.

[0020] The features and advantages of the present invention will become apparent by reading the following description, given by way of example only and not by way of limitation, with reference to the accompanying drawings.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0022] Referring to all the figures, especially FIGS. 3, 4, and 6, the electrification system for the ship 30 is configured to be connected to an electrical energy source (not shown), such as a battery, which is also arranged above or inside the ship 30.

[0023] As can be seen from the embodiment of FIG. 4, this system includes a watertight enclosure 1 intended to be incorporated above or inside the ship 30 with electric assistance. In this embodiment, the ship 30 is of the surfboard or paddleboard type.

[0024] The ship 30 is provided with propulsion means 20 intended to enable movement in water, such as a propeller 20, which is connected to one end of the shaft 4 of the powering system described later. The other end of the pin 4 is arranged inside the enclosure 1 and thus not visible in FIG. 4. The ship 30 also includes the above-described electrical energy source (not shown).

[0025] The first elongated assembly 5 of the cooling means of the powering system, and optionally the second elongated assembly 6 in the embodiment of FIG. 6 (which will also be described in detail later), protrude from the enclosure 1 by one of their ends, and the other end is arranged inside the enclosure 1 and thus not visible in FIGS. 3, 4, and 6.

[0026] The entire powering system is incorporated into the ship 30, and as a result, this end of the first elongated assembly 5 (and optionally the second elongated assembly 6) protruding from the enclosure 1 is located in the surrounding water when the ship is in the water or on the water surface.

[0027] Therefore, when electrical energy is supplied to the powering system by an electrical energy source, the propulsion means 20 is driven by the shaft 4, and the powering system can be cooled by heat exchange between the end of the first elongated assembly 5 (and optionally the second elongated assembly 6) protruding from the enclosure 1 and the surrounding water.

[0028] In the embodiments of FIGS. 4, 5, and 6, the enclosure 1 is particularly closed by the wall 15, and through this wall 15, the shaft 4 and the first elongated assembly 5 (and optionally the second elongated assembly 6) protrude in a watertight state, extend beyond this wall 15 to form a turbine, and the propulsion means 20 is protected and operates inside the turbine.

[0029] This wall 15 is inclined with respect to the shaft 4 and the longitudinal axis of the ship 30, and does not cause surface rupture with respect to the main surface of the ship 30, which may be harmful to the hydrodynamics and performance of the propulsion means 20.

[0030] In the embodiments of FIGS. 3, 4, and 6, the end of the first elongated assembly 5 (and optionally the second elongated assembly 6) protruding from the enclosure 1 is on the same plane as the surface of the wall 15. In order to obtain the desired cooling effect, a larger protrusion is not necessarily required, and here too, it may damage the hydrodynamics and performance of the propulsion means 20. Also, when this wall 15 is inclined as described above, the end of the first elongated assembly 5 (and optionally the second elongated assembly 6) protruding from the enclosure 1 may be chamfered so that this end follows the inclined surface of the wall 15.

[0031] In a variant embodiment, the turbine part of the enclosure 1 is not present at all in a simple manner, the part of the shaft 4 projects from the enclosure 1, and the propulsion means 20 is housed in a housing provided on the ship 30 which is an extension of the enclosure 1, or extends beyond the outside of any housing from the ship 30.

[0032] Alternatively, the turbine part may be present, but is separate from the enclosure 1.

[0033] Referring to all the figures, especially Figures 1, 2 and 5, the power system comprises a rotor 2 and stators 3, 7 arranged inside the watertight enclosure 1. The shaft 4 is connected to the rotor 2 by a first end and projects watertightly outside the enclosure 1 by a second end opposite the first end and, as described above, can be connected to the propulsion means 20 of the ship 30. Gasket-type sealing means 14 are provided to ensure the watertight seal of the enclosure 1 at the level of the passage of the shaft 4.

[0034] Therefore, when electrical energy is supplied to the system, the rotor 2 begins to rotate, drives the shaft 4 by this rotation, and finally rotates the propulsion means 20, thus propelling the ship 30.

[0035] Cooling means 5 (in the embodiments of Figures 1 to 4) or cooling means 5, 6 (in the embodiments of Figures 5 and 6) are provided. These means 5, 6 are at least partially made of metal and include one or more elongated assemblies 5, 6, each having a first end arranged inside the enclosure 1. These elongated assemblies 5, 6 also project watertightly outside the enclosure 1 through their respective second ends opposite the first ends. Gasket-type sealing means 13, 16 are provided to ensure the watertight seal of the enclosure 1 at the level of the passage of each of the elongated assemblies 5, 6.

[0036] Accordingly, the heat generated inside the enclosure due to the operation of the powering system, particularly the rotation of the rotor 2, is conducted from the inside to the outside of the enclosure 1 along the elongated assemblies 5, 6.

[0037] In the illustrated embodiment, the first end of the first elongated assembly 5 is fixed to the stators 3, 7.

[0038] Strictly speaking, the stators 3, 7 can comprise a stator portion 3 and a fixing element 7, such as a fixing plate 7. In this case, the first end of the first elongated assembly 5 is preferably fixed to this fixing element 7.

[0039] The first elongated assembly 5 comprises at least one first part, such as a rod 5, which is integrally formed with at least a part of the stators 3, 7.

[0040] Alternatively, the first elongated assembly 5 comprises at least one first part, such as a rod 5, which is press-fitted into a housing provided in the stators 3, 7. In this case, the housing contains a heat-conductive paste-like material, such as heat-conductive silicone.

[0041] In the embodiment shown in the figures, regardless of whether the first elongated assembly 5 is integrally formed with any part of the stators 3, 7 or press-fitted into a housing provided in the stators 3, 7, the first elongated assembly 5 is integrally formed by a heat-conductive metal rod 5.

[0042] An electronic control unit 10 is provided and configured to control the operation and power supply of the powering system.

[0043] Such a control unit conventionally comprises a microcontroller arranged in an electronic circuit formed on an electronic substrate 11.

[0044] This control unit 10 is fixed to the stator 3, 7, for example, via a fixed support 12 which is itself directly attached to the stator part 3 or the fixed element 7. In this case, the electronic board 11 is supported by the fixed support 12 while being electronically connected to the stator 3, 7, in particular by connection means.

[0045] Accordingly, a heat path is created between the control unit 10 and the first elongated assembly 5, and the first elongated assembly 5 also ensures the cooling of the control unit 10. In fact, this configuration enables the heat released by the control unit 10 to be conducted along this heat path and the first elongated assembly 5 towards the outside of the enclosure 1.

[0046] Alternatively, or additionally, as shown in the embodiments shown in FIGS. 5 and 6, the cooling means 5, 6 of the powering system have at least one second elongated assembly, in this case the elongated assembly 6 already described above.

[0047] Similar to the first elongated assembly 5, this second elongated assembly 6 is at least partially made of metal. It is also fixed to the control unit 10 by a first end and projects in a watertight manner outside the enclosure 1 by a second end opposite the first end.

[0048] This configuration enables the conduction of heat from the control unit 10 to the outside of the enclosure 1 along the second elongated assembly 6.

[0049] This second elongated assembly 6 may be a rod 6, similar to the first elongated assembly 5, or may include a rod-shaped portion.

[0050] The rods 5, 6, or the rod-shaped portions of the first and second elongated assemblies 5, 6 respectively preferably have a substantially circular cross-section.

[0051] The sealing means 13, 16 described above may be O-rings.

[0052] As shown in the figure, each second end of the first and / or second elongated assemblies 5, 6 has slats 8, 9 formed at intervals and parallel to the axes of the first and second elongated assemblies 5, 6, respectively.

[0053] This configuration increases the heat exchange area between each end of the first and second elongated assemblies 5, 6 and the surrounding water when the powering system is incorporated into the ship 30 and the ship 30 is placed in water or on water. Therefore, the slats 8 arranged at the second end of the first elongated assembly 5 and the slats 9 arranged at the second end of the second elongated assembly 6 form radiators that enable the heat to be more rapidly dispersed into the surrounding water due to the increased heat exchange area.

[0054] Also, as shown in the figure, in the illustrated embodiment, the powering system includes a motor portion of the "outrunner" type. Therefore, the rotor 2 is provided with a rotating cage 2, and the stators 3, 7 are provided with a fixed core 3 arranged inside the cage 2.

[0055] As described above, this configuration is particularly interesting because it enables the rotor to rotate more slowly than a configuration having a motor of the "inrunner" type (fixed cage and rotating core) by maximizing the diameter of the interaction between the centrally arranged coil and the peripherally arranged magnet. Therefore, this configuration does not require the use of a speed reducer, and the cost and maintenance are reduced.

[0056] To ensure the heat generated by the operation of the motor and conduct it to the outside, by relying on the fixed elements inside the enclosure 1 such as the stators 3, 7, the conventional solutions for cooling an "outrunner" type motor such as the water circulation system inside the fixed part of the motor, and their complexities (pipes, inlets, and water outlets inside the motor) are also overcome.

[0057] Alternatively, the powering system can include an "inrunner" type motor portion having a rotating core and a stationary outer cage that can form the enclosure 1.

[0058] In this case, the first elongated assembly 5 (and optionally the second elongated assembly 6) can be installed on the enclosure 1 that forms the stationary part of the motor in order to secure the heat generated by the operation of the motor and conduct it to the outside.

[0059] It should be remembered that this description is given by way of example and is not intended to limit the invention.

[0060] In particular, while finding particularly interesting applications in the field of surfboards, the invention is not limited to surfboard - type vessels and extends to vessels such as paddleboards or windsurfing boards.

[0061] More generally, the invention is not limited to board - type vessels and extends to any electrically assisted vessel such as a canoe or a kayak.

Claims

1. 1. An electrification system for a marine vessel (30) configured to be connected to a source of electrical energy, comprising: The system comprises a watertight enclosure (1) intended to be integrated in or on a vessel (30), in which a rotor (2) and a stator (3, 7) are arranged, as well as a shaft (4) connected by a first end to said rotor (2) and projecting in a watertight manner outside said enclosure (1) by a second end opposite said first end, said shaft (4) being adapted by its second end to be connected to a propulsion means (20) of the vessel (30), such that, when electrical energy is supplied to the system, said rotor (2) starts to rotate and drives said shaft (4) in said rotation, said system further comprising cooling means (5, 6), said cooling means (5, 6) comprising at least one first elongated assembly (5) at least partially made of metal, a first end of said first elongated assembly being arranged inside said enclosure (1) and said elongated assembly (5) projecting in a watertight manner outside said enclosure (1) with a second end opposite said first end, allowing the conduction of heat from the inside to the outside of said enclosure (1) along said first elongated assembly (5); and an electronic control unit (10) configured to control the operation and power supply of the system and fixed to the stator (3, 7), forming a thermal path between the control unit (10) and the first elongated assembly (5) to allow heat emitted by the control unit (10) to be conducted along the thermal path and the first elongated assembly (5) to the outside of the enclosure (1); The rotor (2) comprises a rotating cage (2). A system characterized in that

2. 2. The system according to claim 1, characterized in that a first end of the first elongated assembly (5) is fixed to the stator (3, 7).

3. 3. The system according to claim 2, characterized in that the stator (3, 7) comprises at least one fixed element (7), and a first end of the first elongated assembly (5) is connected to the fixed element (7).

4. 4. A system according to claim 2 or 3, characterized in that the first elongated assembly (5) comprises at least one first portion integrally formed with at least a part of the stator (3, 7).

5. 4. The system according to claim 2 or 3, characterized in that the first elongated assembly (5) comprises at least one first part pressed into a housing provided on the stator (3, 7), the housing comprising a thermally conductive material in the form of a paste.

6. 6. The system according to claim 4 or 5, characterized in that at least one first part of the first elongated assembly (5) is a rod.

7. The system of claim 6 , wherein the rod has a substantially circular cross section.

8. 8. A system according to claim 7, characterized in that the first elongated assembly (5) is a rod (5) of circular cross section projecting in a watertight manner from the enclosure (1) by means of an O-ring (13).

9. 9. The system according to claim 1, further comprising an electronic control unit (10) arranged inside the enclosure (1) and configured to control the operation and power supply of the system, characterized in that the cooling means (5, 6) comprise at least one second elongated assembly (6) at least partly made of metal, fixed by a first end to the control unit (10) and projecting in a watertight manner outside the enclosure (1) by a second end opposite to the first end, allowing the transfer of heat from the control unit (10) along the second elongated assembly (6) to the outside of the enclosure (1).

10. 10. The system according to claim 9, characterized in that at least a part of the second elongated assembly (6) is a rod having a substantially circular cross section.

11. 11. The system according to claim 10, characterized in that the second elongated assembly (6) is a rod (6) of circular cross section projecting in a watertight manner from the enclosure (1) by means of an O-ring (16).

12. A system according to any one of claims 9 to 11, characterized in that the second end of the first elongated assembly (5) or the second end of the second elongated assembly (6) or both have slats (8, 9) which are spaced apart and whose longitudinal direction extends parallel to the axes of the first and second elongated assemblies (5, 6), respectively.

13. A system according to any one of the preceding claims, characterized in that the rotor (2) comprises a rotating cage (2) and the stator (3, 7) comprises a stationary core (3) arranged inside the cage (2).

14. An electrically assisted vessel (30) comprising propulsion means (20) capable of propelling said vessel (30) on or through water, and a source of electrical energy, The motorisation system according to any one of claims 1 to 13, further comprising the watertight enclosure (1) integrated on or in the vessel (30), the shaft (4) being connected by its second end to the propulsion means (20), the supply of electrical energy from an electrical source to the motorisation system allowing the driving of the propulsion means (20) and the cooling of the motorisation system by heat exchange between the second end of the first elongated assembly (5) and ambient water. Ship (30).

15. 15. A watercraft (30) according to claim 14, characterized in that said watercraft is a surfboard, or a paddleboard, or a windsurfing board, or a canoe or kayak type.

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