Improvements to controllable blade fluidic rotors

Abstract

A rotor with controllable blades is proposed, comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the variations in the tilt of said rotating structure as a function of its angular position. This mechanism comprises, in association with each blade, a driven element synchronized with a corresponding driving element located on the rotor axis via a closed link such as a toothed belt or chain. The mechanism is characterized in that one of the elements is circular and the other is non-circular, with the same number of teeth as the circular element, so as to directly control the angular position variations of the blades during the rotation of the rotating structure. Other improvements are proposed.

Description

Title of the invention: Improvements to fluidic rotors with steerable blades

[0001] This memorandum describes a number of improvements made to fluidic rotors (hereinafter referred to as trochoidal type rotors encompassing sinusoidal kinematics) as described in patent applications WO2014006603 (hereinafter patent 1), WO2016067251 (hereinafter patent 2) and WO2017168359 (hereinafter patent 3) in the name of the Applicant.

[0002] According to a first aspect, a rotor with steerable blades is thus proposed, comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the variations in blade inclination as a function of the angular position of said structure, according to a pitch law, said mechanism comprising for each blade a transmission in a generally radial direction between a driving element rotating with the rotor and a driven element eccentrically at the level of the blade, characterized in that it comprises a means for varying the pitch law by means of a central control comprising a control element adapted to move along the main axis and a set of return elements adapted to generate a displacement of the driven elements respectively associated with each blade,namely either radial movement using sequential control, or circumferential movement using continuous control (PART 1).

[0003] According to a second aspect, a nautical craft is proposed, comprising a pair of main propellers including counter-rotating rotors, each steerable-bladed rotor including a structure rotating about a main axis and including a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the variations in inclination of said rotating structure as a function of its angular position so as to exert a thrust on the water in a determined direction, characterized in that means are provided for directing the thrusts of the two rotors in two generally opposite lateral directions in order to ensure braking of the craft, the craft being able to also include at least one bow thruster and / or at least one secondary thruster (PART 2).

[0004] According to a third aspect, a nautical craft is proposed, comprising a pair of propulsion units including counter-rotating rotors, each rotor comprising a structure rotating about a main axis and comprising a set of blades rotating around a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the inclination variations of said rotating structure as a function of its angular position so as to exert a thrust on the water in a determined direction, characterized in that it provides thrust correction means capable of adjusting the thrust direction of each rotor on either side of a direction located along the main axis of the machine (PART 3).

[0005] A fourth aspect is proposed: a rotor with steerable blades, comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the variations in inclination of said rotating structure as a function of its angular position, characterized in that each blade is at least partially elastically deformable, and in particular comprises a non-deformable leading edge and an elastically deformable trailing edge. (PART 4).

[0006] A fifth aspect is proposed, a rotor with steerable blades, comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the inclination variations of said rotating structure as a function of its angular position, said mechanism comprising in association with each blade a driven element synchronized with a corresponding driving element located on the axis of the rotor via a closed link such as a toothed belt or a chain, characterized in that one of the elements is circular, and the other element is non-circular, typically elliptical, with a number of notches or teeth identical to that of the circular element, so as to directly ensure the angular position variations of the blades during the rotation of the rotating structure (PART 5).

[0007] A sixth aspect is proposed, a rotor with steerable blades, comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the inclination variations of said rotating structure as a function of its angular position, this mechanism comprising a first element carrying a finger and a second element eccentric with respect to the first and having a slot in which the finger is engaged, characterized in that it comprises a play compensation device between the finger and the slot.

[0008] A seventh aspect is proposed: a rotor with adjustable blades, comprising a structure rotating about a main axis and comprising a set of blades rotating around a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism associated with each blade to control the variations in inclination of said blade as a function of the angular position of said rotating structure, said mechanism comprising a set of generally radial transmissions between driving elements arranged adjacently at the level of the rotor axis and each of said mechanisms, and further comprising a disengagement and reset mechanism comprising a key capable of moving along the rotor axis relative to said driving elements,characterized in that said disengagement and reset mechanism belongs to a group comprising (i) a key capable of selectively engaging directly with each of the driving elements and actuated by an elastic means acting along the axis of rotation of the rotor, sequentially engaging each of said driving elements when they are rotated, and (ii) a primary key capable of selectively actuating a set of secondary keys themselves elastically actuated in a direction transverse to the axis of the rotor and respectively engaging with the respective drive elements (PART 7).

[0009] An eighth aspect is proposed, a rotor with steerable blades, comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and means for controlling the tilt variations of each blade as a function of the angular position of the rotor, characterized in that said means comprise a set of individual actuators controlled non-mechanically from the rotor to individually vary in a potentially adjustable and potentially programmed manner the tilt variations of the associated blade (PART 8).

[0010] A ninth aspect is proposed, a rotor with steerable blades, comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the variations in inclination of said rotating structure as a function of its angular position, said mechanism comprising in association with each blade a driven element synchronized with a corresponding driving element located on the axis of the rotor via a closed link such as a toothed belt or a chain, characterized in that it comprises a mechanism for maintaining tension on each link, comprising in particular a movable element in contact with said link and subjected to the centrifugal force generated by the rotation of the rotor (PART 9).

[0011] According to a tenth aspect, a rotor with adjustable blades is proposed, comprising a structure rotating about a main axis and comprising a set of blades rotating around a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the inclination variations of said rotating structure as a function of its angular position, said mechanism comprising in association with each blade a driven element synchronized with a corresponding driving element located on the rotor axis via a closed link such as a toothed belt or a chain, characterized in that it comprises a tensioning mechanism for each link, comprising in particular a movable element in contact with said link and subjected to a movable member intended to vary the maximum amplitude of the inclination variations of the associated blade (PART 10).

[0012] According to an eleventh aspect, a nautical machine, in particular a sailboat, is proposed, comprising an engine coupled to a submerged steerable-bladed rotor, said rotor comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the variations in inclination of said rotating structure as a function of its angular position, characterized in that the rotor has a first mode of operation as a propulsion unit by being driven by the engine, and a second mode of operation as a drift or rudder (PART 11).

[0013] A twelfth aspect is proposed, a rotor with steerable blades, comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the inclination variations of each blade as a function of the angular position of said rotating structure, each blade being mounted in cantilever on said rotating structure, characterized in that it provides devices for quick mounting of the blades on rotating supports subjected to said mechanism (PART 12).

[0014] A thirteenth aspect of a steerable bladed ore is proposed, comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the variations in inclination of said rotating structure as a function of its angular position, said mechanism comprising in association with each blade a driven element synchronized with a driving element located on the axis of the rotor via a closed link such as a toothed belt or a chain, characterized in that a single link is provided between a single driving element located on the axis of the rotor and said driven elements (PART 13).

[0015] Other aspects, purposes and advantages of the inventions will become clearer upon reading The following detailed description of preferred embodiments is given by way of example and with reference to the accompanying drawings. On the drawings:

[0016] [Fig.1A] is a perspective view of a mechanism according to a first improvement,

[0017] [Fig.1B] and [Fig.1C] are perspective views from two different angles of a mechanism according to another embodiment of this first improvement,

[0018] [Fig.2] is a schematic top view of a nautical craft comprising a second improvement,

[0019] [Fig.3A-B] are schematic top views of thrusters illustrating a third improvement,

[0020] [Fig.4A] and [Fig.4B] are perspective views of a blade with a fourth improvement,

[0021] [Fig.5] is a schematic plan view of a motion transmission according to a fifth improvement,

[0022] [Fig.6A-C] are respectively a front view, a side view and a perspective view of a mechanism according to a sixth improvement,

[0023] [Fig.7A] and [Fig.7B] are perspective views of a mechanism according to a seventh improvement,

[0024] [Fig.7C][Fig.7D] are axial cross-sectional views of a mechanism according to another embodiment of this seventh improvement,

[0025] [Fig.8] is a schematic elevation view illustrating an eighth improvement,

[0026] [Fig.9] is a perspective view of a mechanism according to a ninth perfect operation,

[0027] [Fig.1OA], [Fig.1OB] and [Fig.1OC] are respectively an elevation view in a first state, an elevation view in a second state and a perspective view of a mechanism according to a tenth improvement,

[0028] [Fig. 11] is a schematic side view of a boat with a propulsion system according to an eleventh improvement,

[0029] [Fig. 12] is a perspective view of a base according to a twelfth improvement, and

[0030] [Fig. 13] is a front view of a transmission according to a thirteenth improvement. DETAILED DESCRIPTION

[0031] PART 1 - Propulsion mode - variation of the timing law

[0032] Patent 3 describes the possibility of varying the pitch law of a rotor used in propulsion mode as a function of speed. The pitch angle is defined by the direction of the front / rear axis of the blade relative to the tangent to the circular motion of the blade.

[0033] First, it is necessary to introduce the concept of forward speed X: this is defined as the speed of the vessel relative to the speed of the blade in its rotation. The higher the pitch angle, the higher the thrust, and the lower the forward speed. The lower the pitch angle, the lower the thrust, but the higher the forward speed, and therefore the greater the efficiency. For example, with a pitch angle of 10°, efficiencies of approximately 80% can be achieved at forward speeds X of 2.5: this means that the vessel is moving twice as fast as the blade. In other words, under these conditions, the propeller rotates very slowly to propel the vessel forward, resulting in reduced cavitation and a very low acoustic signature. As an example, a 3.20 m diameter propeller would rotate at only 31 rpm to propel a vessel at 25 knots (Note: forward speed of 2.5).It is easy to understand that being able to control the propeller pitch in real time is particularly relevant because it optimizes operation and fuel consumption: a high pitch during the ship's start-up phases (or takeoff on an aircraft or VTOL) maximizes thrust, while a lower pitch is used to achieve speed. This can be done manually or, more advantageously, with a programmable logic controller (PLC) that takes the following inputs: ship speed, propeller RPM(s), and power or torque consumption. Finally, being able to set the pitch to zero minimizes blade drag, which, for example, in a sailboat propulsion application, reduces drag while maintaining directional control because each blade then acts as a rudder (the pitch can be set to zero, but directional control is still retained – see also PART 11).

[0034] It is worth recalling that real-time pitch adjustment is highly relevant in energy recovery applications, for example, to regulate power in wind turbine applications and even manage storm conditions. It is known that the larger the pitch angle (for example, 50°), the higher the efficiency (Cp: coefficient of performance) with a TSR (Tip Speed ​​Ratio: defines the rotor speed versus the wind speed) close to 1. The smaller the pitch angle, the lower the Cp, along with the TSR. As with conventional variable-pitch wind turbines, it is therefore highly relevant, once the generator's maximum power is reached, to decrease the pitch angle to regulate the power down to the cutoff speed, typically around 25 m / s.

[0035] To achieve real-time pitch control, it is necessary to be able to vary the position of the slotted disc (see patent 3) relative to the blade's axis of rotation. When these axes are aligned, the pitch is at 0°. The further apart they are, the greater the pitch angle. It is preferable to vary the position of the slotted disc's axis of rotation.

[0036] This can be done as described in patent 3 either along a radius of the rotor, or via a variation by means of an eccentric at the end of the arm (these first two solutions being the most suitable for large diameter rotors), or along an arc of a circle, the preferred solution on smaller diameter rotors, for example for ship propellers.

[0037] In the first case, the difficulty arises from the method used to transmit the motion to the slotted disc from the central drive shaft of the rotor. If belts or chains are used, it is necessary to maintain optimal tension, which requires a control system for the tensioning mechanism. In the case of gears, it is necessary to vary the position of the intermediate gear. In the case of a right-angle drive, it is possible to use a splined pinion that can slide along the transmission shaft (see also later at the end of PART 10).

[0038] The second solution is simpler because by varying it along an arc of a circle, the distance between the axis of rotation of the slotted disk and the center of the thruster is not changed. Therefore, this latter solution will be preferred.

[0039] We will now describe two approaches.

[0040] A - sequential mechanical approach

[0041] With reference to [Fig. 1A], we will describe a mechanism inspired by the sequential controls of motorcycle gearboxes. A control shaft 11 extending along the rotor axis is actuated in translation by an actuator (electrical, mechanical, pneumatic, hydraulic) not shown in this drawing. The control shaft is fixed in rotation and therefore does not rotate with the rotor. It adopts one of three defined positions: a neutral position, a position to raise the control law by one step, and a position to lower the control law by one step. This mechanism is designed such that when the kinematic law is set, no force is exerted by this control shaft. The control shaft 11 is connected to a part 12, for example, via bearings or ball thrust bearings. This part 12 rotates simultaneously with the rotor. For each blade mechanism, it actuates via a pallet 12a a fork 13 through a pair of rollers 13a.This fork 13 drives, via a connecting rod 14, a lever 15. This lever 15 actuates a ratchet wheel 16a, which is rotationally fixed to a stabilizing disc 16b with peripheral grooves. A roller 17a, supported by a plate 17 and held under pressure by a spring 18, rests on this disc. The spring 18 stabilizes the angular position of an axis 19 without affecting the upstream control. The axis 19 terminates in a ball screw 19a, which allows translational movement of a plate 19b. The various end-of-arm components (a slotted disc in the case of patent 3) are mounted on this plate. This is used to raise or lower the control curve. from a maximum angle to a minimum angle the control axis 11 must be moved several times in the appropriate direction.

[0042] Note: [Fig.1A] illustrates the case of a single-arm rotor, but the mechanism could be reused in a cassette rotor.

[0043] B - Direct drive mechanical approach - cassette rotor

[0044] With reference to Figs. IB and IC, this mechanism is inspired by the mechanical pitch control systems of helicopter tail rotors. At the top of the rotor, a fork 151 is actuated by an actuator via a connecting rod 152. The fork 151, by means of rollers 153a, allows a control shaft 153 to be moved in translation, which rotates with the rotor. At the end of this control shaft 153 is fixed a part 154 to which the ends of two connecting rods 155 are attached. The other ends of these connecting rods are fixed to L-shaped linkages 156 pivoting on axes 156a fixed to the rotor. On the other ends of these "L" shaped links are fixed connecting rods 157 which have respective fingers allowing the cassette 158 which holds the gear trains and the slotted discs of the blade tilt controls to be rotated a few degrees relative to the rotor body.

[0045] More specifically, by lifting the shaft 153, the part 156 takes on an oblique orientation, thus shortening the circumferential distance between the attachment on the connecting rod 155 and the finger 157a. The shaft 156a fixed to the rotor passes through an oblong slot in the cassette 158 to allow this movement.

[0046] By varying this cassette in the rotor body by a few degrees, it is easy to understand that the distance between the axes of rotation of the slotted discs and the axes of rotation of the blades, which are fixed in the rotor body, is varied.

[0047] PART 2 - Propulsion mode - braking

[0048] A person skilled in the art would expect that, in order to brake a vessel propelled by a pair of trochoidal rotors, the rotor control would be reversed so that they jointly exert a forward thrust on the vessel. However, with reference to [Fig. 2], it was unexpectedly discovered that effective braking could be achieved not by directing the flow forward, but laterally, with the left rotor RG producing a leftward thrust, preferably at an angle of between 60 and 120° to the left of the vessel's axis, and the right rotor RD producing an identical rightward thrust. This approach also makes it possible to significantly reduce the stresses applied to the blades of each rotor.

[0049] Conventional braking by directing the airflow forward is also possible. It is also advantageous in terms of responsiveness because it is not necessary to reverse the direction of rotation of the propeller as with a conventional propeller without variable pitch.

[0050] PART 3 - Propulsion mode - optimal flow orientation

[0051] A person skilled in the art would expect that in propulsion with a pair of counter-rotating rotors, the thrust will be optimal if the two rotors exert a thrust on the liquid medium in two directions parallel to each other, along the axis of the boat.

[0052] It may be relevant to use two non-parallel thrust directions for the two rotors. These directions may be either divergent, parallel, or convergent.

[0053] Simulations show that for a given operating point, the flow is not perfectly aligned with the direction of travel of the vessel. Fig. 3B thus illustrates an optimum setting for a given operating point which shows a slight pinch (of a few degrees) in the pitch laws in order to optimally direct the flows generated by the thrusters, compared to the case of Fig. 3A where there is no pinch.

[0054] In one approach, diverging directions can be predicted for slow speeds, and converging directions for high speeds. The convergence / divergence angle can also be adjusted according to the acceptable level of disturbance for the aquatic environment, or the maneuverability of the vessel.

[0055] PART 4 ​​- All applications - elastically deformable blades

[0056] According to this improvement, the rotor blades exhibit elastic deformability in bending so that their profile can deform. This makes it possible to better separate the water flow and to significantly increase the aerodynamic or hydrodynamic performance of the blades.

[0057] This deformability can be achieved by using a homogeneous elastically deformable material for the blades, in which case their decreasing thickness towards the trailing edge makes them more easily deformable in this region. This arrangement improves the smoothness of operation, limits the mechanical stresses applied to the blades, and improves efficiency.

[0058] Figs. 4A and 4B illustrate (the view in [Fig. 4B] being semi-transparent) an example of a semi-deformable blade P: only the trailing edge region PF of the blade is made of a deformable material (e.g., rubber, reinforced or unreinforced). According to one embodiment, this flexible part can be threaded via a dovetail 41 into a complementary forge 42 provided at the rear of the rigid leading edge PA of the blade. Bonding can also be considered if the materials allow it.

[0059] The location of the transition zone between these two parts can be chosen according to the application, and will typically be located between 1 / 3 and 2 / 3 of the blade length between the leading edge and the trailing edge.

[0060] Reference 43 designates a blade frame, embedded in the leading part PA.

[0061] PART 5 - All applications - pitch control without eccentric

[0062] With reference to [Fig. 5], a control for tilting the satellite or has been illustrated The nacelle is associated with each blade not by an eccentric movement, but by a slip-free transmission (chain, toothed belt, etc., designated by reference numeral 51) in which one of the sprockets 52 is circular, and the other sprocket 53 is non-circular—for example, ovoid or elliptical—with the same number of teeth or notches as the circular sprocket. One of the sprockets is on the main rotor axis, without the possibility of rotation, while the other sprocket (the satellite) is directly meshed with the blade axis. It is understood that during rotor rotation, the blade tilt is caused by the difference in the angular path of the satellite sprocket relative to the central sprocket, due to the fact that the local radius of one of the sprockets varies continuously while the local radius of the other sprocket remains constant.

[0063] If necessary, a chain or belt tensioner is provided to compensate for variations in the development of the chain / belt in its contact area with the non-circular sprocket when the latter rotates.

[0064] A particularly simple and economical control of the blade angle is achieved.

[0065] The non-circular pinion 53 can either be on the rotor shaft or be the satellite.

[0066] This approach requires that the circumference of the ellipse and the circle be strictly The design is identical to avoid creating a desynchronization of the kinematics. Its main advantage is simplicity in terms of the number of parts, provided a constant sprocket ratio is appropriate. It is understood that the smaller the aspect ratio of the ellipse, the smaller the sprocket angle will be, and vice versa. Additionally, one could consider, for example by drawing inspiration from bicycle derailleurs, the possibility of switching from one elliptical sprocket to another with a different aspect ratio to vary the sprocket ratio.

[0067] PART 6 - All applications - Compensation of backlash in the finger and slot mechanism

[0068] In patent 3, play may occur, particularly due to wear, between each finger and the slot in which it slides, creating jerks in the movement of the blades. To remedy this, each finger is provided with a backlash compensation function, for example by comprising a series of elements held together by a cage and elastically forced outwards by an elastic means such as a spring. Figs. 6A-6C illustrate, by a front view, a side view, and a perspective view, an example of an embodiment of such a mechanism, where, instead of a simple slot, two shafts 61 are provided on which a carriage 62 slides, for example, by means of ball bushings 63. This carriage carries a shaft 64 on which is mounted the crankpin 65 of the blade crankshaft connecting rods as described in Patent 3. This mechanism eliminates mechanical play in the blade alignment and reduces noise. Alternatively, a carriage can be mounted directly on one or more guide rails.

[0069] VII - Securing and rearming

[0070] Patent 3 describes a feathering with a groove and key mechanism that can be acted upon electromechanically or purely mechanically, thus totally freeing the rotating blades and thus neutralizing the operation of the machine.

[0071] A device is proposed here allowing the rotor to be secured and its automatic reset, based on an automatic locking / unlocking key operating between the rotor shaft and each pulley (or pinion in the case of a chain or gear transmission) located on the rotor shaft and allowing the control of the variation of the inclination of the respective blade.

[0072] When the safety mechanism needs to be activated, for example in the event of wind exceeding a threshold for wind turbine applications, a linear actuator such as an electric cylinder acts on a rod which allows the key to be disengaged, as will be seen in detail later.

[0073] When resetting is initiated, the actuator returns to its initial position. It does not pull on the central rod directly, but rather via a spring, which allows the key to exert pressure on the first pulley to be re-engaged. In one embodiment, a cam roller or other sliding element can be arranged to facilitate the key's movement on the pulley surface. The first blade pulley can be reset according to the wind direction, but it may be preferable to activate the rotor's yaw control mechanism (yaw actuator) to cause the central yaw control (pulley support piece) to make several successive rotations, thus ensuring the key passes through the groove of the respective pulley.This reset procedure requires sufficient wind to maintain each blade, and therefore its associated axial pulley, in a given position while the central part supporting the spar rotates via the yaw actuator. The control spring is calibrated so that successive resets of the various axial pulleys are performed until the machine is fully reset.

[0074] Figs. 7A and 7B illustrate a particular embodiment of this safety and reset system. An actuator 71 drives in translation an assembly E consisting of parts 72, 73 and 74. The assembly E is prevented from rotating by a part 75 which slides in a slot attached to the body of the rotor base (not shown here). The assembly E drives in translation a safety rod 76 which forms at its free end a key 77 that engages or disengages from slots made in the axial pulleys of the rotor and which allows them to be prevented from rotating or not. Thus When the key is released, the mechanisms are disengaged, the pulleys are free to rotate and the blades also become free to rotate, which notably allows feathering in case of excessive wind.

[0075] Conversely, for resetting, assembly E acts on the rod 76 via a compression spring 74. Thus, when this spring is compressed, the resetting procedure can be initiated: the yaw actuator rotates a central part 78 of the rotor which holds the pulleys until the key is aligned, sequentially, with the corresponding pulley housings. The key then moves step by step, by a increment equal to the thickness of the pulley, and this continues successively until all the pulleys are reset to rotation.

[0076] Figs. 7C and 7D illustrate another pulley locking system. This mechanism is similar to a clutch system with indexing of the elements to be locked, in this case the pulleys. It comprises a primary key 701 having three slots 701a which allow three indexing fingers 702, forming secondary keys, to be released or retained. These are arranged to fit into grooves formed in the respective pulleys P. Depending on the position of the key: in one case ([Fig. 7C]) it removes the fingers 702 from the pulley slots; in the other case ([Fig. 7D]) it releases the fingers 702, which tend to press inwards towards the pulleys by means of respective springs 704. Advantageously, friction elements such as Ferrodo washers are provided between each pair of pulleys. When the key is in the disengagement position, it fully decompresses an end spring, thus allowing each pulley to be free relative to the others.When the reset procedure is initiated, the key first descends sufficiently to release the fingers. The reset procedure with the yaw actuator is then launched, moving the central part 701, which holds the fingers 702, into position opposite the grooves of the pulleys. Once this step is completed, the key is pulled back into its clutch position, compressing the spring and thus locking the assembly together. The advantage of this solution lies in the fact that the forces during operation are no longer borne by the key and its housings in the pulleys, resulting in increased reliability.

[0077] PART 8 - Offsetting the pitch control to the end of the arm

[0078] Whereas in patents 2 and 3 the pitch control is carried out in a common way from a central action, (typically by angular control around the main axis of the rotor in patent 3), here an individual pitch control 82 is carried out at the end of each arm 81.

[0079] This control can be electromechanical, with an actuator individually controlling, for example, the position of the axis of the slotted element relative to the axis of the finger element according to the mechanism of patent 3.

[0080] The power supply for such an actuator, as well as the control instructions which can be implemented by power line carriers, can be transmitted (reference 83) via sliding contacts on the main shaft 84 of the rotor. Alternatively, wireless power transmission by magnetic coupling can be provided if the required electrical power of the satellite control allows it.

[0081] With such individual control, it becomes possible to generate a control law for the inclination of any blade 85, in particular programmable, in particular in order to optimize the efficiency of the machine in both generator mode and propulsion mode.

[0082] PART 9 - Belt transmission - maintaining belt tension

[0083] A toothed belt drive between a central pinion and a planetary pinion is advantageous, particularly in terms of simplicity and cost, and for large rotor sizes. However, as the speed increases, it may be necessary to increase the belt tension, which can then begin to exhibit undesirable vibration.

[0084] This increase in tension can be achieved for example by a weighted device subjected to centrifugal force and exerting on a tensioning element a displacement that is greater the higher the rotational speed.

[0085] Figure 9 illustrates an example of this mechanism. A tension pulley 91 is applied to the belt 96 by being mounted on a plate 92 which pivots on an axis 93 fixed to an arm 94 of the rotor. A weight 95 is mounted at the end of the plate 92. It is understood that with the increase in the rotor's rotational speed, the mass formed by this weight 95 generates a force directed outwards from the rotor under the effect of centrifugal force, which increases the pressure of the tension pulley 91 on the belt 96. The various parameters are determined so as to ensure a satisfactory level of tension.

[0086] PART 10 - Belt drive - pitch adjustment

[0087] As seen above and in patent 3, to achieve real-time variation of the blade pitch control law, it is necessary to vary the distance between the blade's axis of rotation and the axis of rotation of the slotted disc or its equivalent. Varying the blade's point of rotation on the rotor appears complicated, so the focus is on varying the position of the slotted disc and its equivalent. In this case, the distance between the central control pulley and the pulley at the end of the arm varies, causing slack in the belt (or chain) when this distance decreases. A system for overcoming this difficulty is described here with reference to Figs. 10A-10C. The slotted disc is fixed to the pulley 101 located at the end of the arm, which is engaged with the belt 101a. This pulley 101 is mounted via bearings. Ball bearings on an eccentric 102. It is understood that by rotating this eccentric, the distance between the axis of rotation of the slotted disc and the axis of the blade, represented by axis 103, is changed. A control rod 104, actuated by a mechanism described in this application or in previous patents, can be moved in translation. This control rod 104 allows, via a connecting rod 105, the angular position of the eccentric to be adjusted. Furthermore, via a second connecting rod 106, which in this embodiment is fixed on the same axis as the connecting rod 105, it allows a plate 107 to be rotated. This plate pivots around an axis 108 and holds a tensioning roller 109. The geometry of the various components is determined so that the roller 109 maintains satisfactory tension on the belt 101a regardless of the angular adjustment of the eccentric.

[0088] According to an alternative embodiment, an automatic spring tensioning device fixed on the plate 107 can be provided, or a tensioning device fixed directly on the arm.

[0089] In the case where a version with bevel gears is used (see Fig. 8B of patent 1) instead of a belt and pulley mechanism, the translational shift of the slotted disc should ideally occur along a radius of the rotor. The connecting shaft between the central bevel gear and the bevel gear on the satellite side is then splined on the satellite side at the point where the slotted disc engages. This allows the plate supporting the slotted disc and the bevel gear to move in translation along a radius of the rotor by sliding on the spline of the connecting shaft.

[0090] PART 11 - Mixed use in nautical applications

[0091] Patent 2 describes the use of a rotor in propulsion mode to propel a drone or marine craft, and in generator mode when the craft is moored, to generate electricity on board by harnessing ocean currents. With reference to [Fig. 1 1], when sailing, the blades 111 can either be free so as to adapt immediately to the direction of the water flow while minimizing drag, or held fixed and preferably in line with the axis of the boat 112, with their leading edge towards the bow, so as to generate a keel or leeway effect.

[0092] Another possibility is to orient the blades by controlling them on the rudder (in the case where the rotor is towards the rear of the boat) so as to assist the boat during tacks to give them an auxiliary rudder function.

[0093] PART 12 - Replacement of the blades

[0094] According to an advantageous aspect, a mechanism can be provided allowing the easy replacement of a broken or damaged blade.

[0095] This applies particularly to the mounting of the blades in cantilever, whether in generation mode or propulsion mode.

[0096] With reference to [Fig. 12], each blade structure thus includes an overhanging armature axis (not shown) which is inserted into a sleeve 123 formed in a plate 122 associated with the respective blade, the plates being rotationally mounted in a support structure 121.

[0097] Translational fastening along the axis can be achieved by any mechanical means such as keying, clipping, screwing, or any combination thereof. Rotational fastening is achieved here by giving the blade's armature axis and its housing a non-circular, in this case oblong, cross-section.

[0098] According to one embodiment, the slotted discs that drive the blades (see patent 3) may be provided with hollow shafts, an access hatch being provided above the rotor so as to allow the insertion of a wrench to tighten a nut that secures a threaded shaft extending from the blade shaft, which has an oblong cross-section. Prior to this, the angular position of the rotor is adjusted to its neutral position (0° pitch angle) so that the blade shafts are aligned with the shafts of the slotted discs.

[0099] PART 13 - Single belt or chain

[0100] With reference to [Fig. 13], an embodiment has been illustrated in which a set of three belts respectively linking three central pulleys fixed in rotation to the axis of the rotor (except when disarmed) to three satellite pulleys, is replaced by a single belt 131 ensuring the engagement of a single axial pulley 132 with three satellite pulleys 133 respectively associated with the mechanisms for varying the inclination of three blades (not shown).

[0101] Such an approach makes it possible to reduce the axial size of the rotor control part.

[0102] Of course, the various inventions described above and shown in the drawings may be subject to numerous modifications and variations. Furthermore, the various inventions may be combined by a person skilled in the art, and such combinations shall be considered as forming part of this description.

[0103] Furthermore, in propulsion applications, a rotor according to one of patents 1 to 3 or according to one of the improvements described in this document can be used for a manned or unmanned craft, submerged or not. For a submerged craft, generally of streamlined shape, several rotors can be provided, having axes of rotation arranged in a star pattern in a plane transverse to the direction of travel. For a hydrofoil craft, a rotor can be integrated into a hydrofoil by giving it an appropriate width.

Claims

Demands

1. Watercraft, comprising a pair of propellers comprising counter-rotating rotors, each rotor comprising a structure rotating about a main axis and comprising a set of blades rotating about a series of blade axes parallel to the main axis and defined by said rotating structure, and a mechanism for controlling the inclination variations of said rotating structure as a function of its angular position so as to exert a thrust on the water in a determined direction, characterized in that it provides thrust correction means capable of adjusting the thrust directions of the two rotors so that they are different and located on either side of a direction located along the main axis of the craft.

2. Watercraft according to claim 1, characterized in that the thrust correction means are configured to direct the thrusts of the two rotors in two generally opposite lateral directions in order to ensure braking of the craft.

3. Watercraft according to claim 2, characterized in that it also comprises at least one of a bow thruster and a secondary thruster.

4. Watercraft according to claim 1, characterized in that the thrust correction means are capable of adjusting the thrust directions of the two rotors between convergent directions and parallel directions.

5. Watercraft according to claim 1, characterized in that the thrust correction means are capable of adjusting the thrust directions of the two rotors between divergent directions and parallel directions.

6. Watercraft according to claim 1, characterized in that the thrust correction means are capable of adjusting the thrust directions of the two rotors according to an acceptable level of disturbance of the aquatic environment.

7. Watercraft according to claim 1, characterized in that the thrust correction means are capable of adjusting the thrust directions of the two rotors according to a desired maneuverability of the craft.

8. Watercraft according to any one of claims 1 to 7, characterized in that each blade is at least partially elastically deformable.

9. Watercraft according to claim 8, characterized in that each blade comprises a non-deformable leading part and an elastically deformable trailing part.

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