FR3033369A1 - WIND TURBINE - Google Patents

Abstract

The wind turbine (10) comprises: - a first shaft (105), called a "hollow shaft", driving a generatrix (110), free in rotation and traversed by an opening (115), - a second shaft (120), said "Solid shaft", positioned at least partially in the opening, fixed in rotation to the hollow shaft, and free in translation in this opening, - at least one third shaft (125), called "support shaft", fixed to the solid shaft along a radial axis and at least partially free in rotation about a longitudinal axis of said support shaft, the longitudinal axis being perpendicular to the axis of rotation of the first and second shafts and - at least one blade ( 130), each blade being secured to a support shaft, said blade having a main axis parallel to the plane defined by the axes of rotation of the first, second and third shafts and outside said plane, so that the main axis of the The blade approaches the plane when the wind force increases.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a wind turbine. It applies, in particular, to wind turbine generators, ie generating an electric current from a kinetic energy of the wind.

STATE OF THE ART Wind turbines with a horizontal axis of rotation usually have a set of blades, similar to aircraft blades, rotating around the axis of rotation. The purpose of these wind turbines is to transform the force of the wind into a rotating force of a shaft, this rotation can cause the generation of electric current. The energy thus transformed has the disadvantage of having the same differences in intensity as those of the wind, the wind can vary greatly in amplitude during bursts, for example. These momentary differences in intensity pose various problems in the exploitation of the energy produced by the wind turbine, especially when it is used to produce an electric current. Indeed, if it is easy to size an electric generator according to the power produced by the shaft of a wind turbine at a constant rotation speed and torque, the difficulty lies in the regulation of this regime and this torque, 25 with very variable wind speeds, according to amplitudes on the one hand and with a large speed on the other hand. The theoretically available energy varies according to the cube of the wind speed; this with the same speed of change as the gusts. Current systems thus have: - low yields due to voluntary limitations of the maximum speed of rotation of the blades or - the risk of damaging the wind turbine during squalls.

By way of example, the majority of low-power wind turbines, ie between 2kW and 20 kW, offer yields of 20 to 35%. According to the Betz Limit, 16/27, or about 59.3%, the maximum energy contained in the wind is captureable and transformable into mechanical energy. Thus, it is understood that the efficiency offered by current wind turbines is well below this limit. Thus, current systems do not allow an optimized and safe performance in transforming the wind force into electrical energy. OBJECT OF THE INVENTION The present invention aims to remedy all or part of these disadvantages. For this purpose, the present invention is directed to a wind turbine, which comprises: a first shaft, called a "hollow shaft", driving a generatrix, free in rotation and traversed by an opening, a second shaft, called a "solid shaft", positioned at least partially in the opening, fixed in rotation to the hollow shaft, and free in translation in this opening, at least one third shaft, called "support shaft", fixed to the solid shaft along a radial axis and at least partially free in rotation about a longitudinal axis of said support shaft, the longitudinal axis being perpendicular to the axis of rotation of the first and second shafts and at least one blade, each blade being integral with a support shaft , said blade having a main axis parallel to the plane defined by the axes of rotation of the first, second and third shafts and outside said plane, so that the main axis of the blade approaches said plane when the wind force increases e. With these provisions, the wind turbine object of the present invention has a variable pitch. When the kinetic energy of the wind in contact with the blades is high, the support shafts rotate so as to reduce the surface of the blade directly perpendicular to the direction of the wind. In this way, the risk of damage caused by a too fast rotation of the hollow shaft or by a too high kinetic pressure of the wind on the blades is limited.

3033369 3 These particular characteristics allow a great reactivity of the wind turbine so as to smooth the important variations of the force of the wind applied to the wind turbine by using the force of the wind and the centrifugal force generated by the rotation of the propeller, l axis of the blade wanting to be in the plane of the blade support axes. These characteristics allow, moreover, to allow the wind turbine to have a nominal power reached at a low wind speed and that this power varies little with the increase in wind speed. In embodiments, the wind turbine that is the subject of the present invention comprises at least one means for mechanically driving at least one support shaft from a first position, in which the main axis of at least one blade is close of the plane, at a second position, in which the main axis of each said blade is remote from said plane, by rotation of the support shaft. These embodiments make it possible to reposition the blade when the wind stops exerting a pressure on the blade so that this blade has a surface perpendicular to the direction of the widest wind possible during the next wind lift. In embodiments, the hollow shaft has, at one end near each support shaft, a plate at least partially surrounding the opening and at least one support shaft is fixed to the plate by at least one bearing. The advantage of these embodiments is that they allow the support shafts to have a degree of freedom in rotation while retaining these shafts in translation.

In embodiments, the wind turbine according to the present invention comprises: a lever, comprising a roller, fixed to at least one support shaft, set in motion by the rotation of said support shaft from a position, called rest ", to a position, called" fallback ", this movement causing a displacement in translation of the solid shaft towards the opening of the hollow shaft and two plates, fixed to the solid shaft, surrounding each roller of in order to allow the rolling of each roller.

These embodiments enable the blade to be repositioned when the wind stops exerting pressure on the blade so that this blade has a surface perpendicular to the widest possible wind direction during the next wind lift.

In embodiments, the mechanical drive means is a spring, attached to the hollow shaft and the solid shaft, being: - at rest when each support shaft is at rest and - deformed when each shaft of support is in a fallback position. The advantage of these embodiments is that they make it possible to perform the mechanical drive function at low cost. In embodiments, the wind turbine according to the present invention comprises a means of mechanically locking the positioning of at least one support shaft as a function of the rotational movement produced by said support shaft.

These embodiments make it possible to lock the wind turbine in a safety position when the gusts of wind are too great and that these bursts may damage the structure of the wind turbine. In embodiments, the hollow shaft and the solid shaft are rotatably connected to each other by protuberances. These embodiments allow the solid shaft to be rotated in rotation when the hollow shaft is set. in motion by the rotation of the blades. In embodiments, the wind turbine of the present invention comprises means for generating electricity from the rotary movement of the hollow shaft.

The advantage of these embodiments is that they make it possible to generate an electric current from the kinetic energy of the wind causing the blades to rotate about the axis of the hollow shaft. BRIEF DESCRIPTION OF THE FIGURES Other advantages, aims and particular characteristics of the invention will become apparent from the following nonlimiting description of at least one particular embodiment of the wind turbine which is the subject of the present invention, with reference to the attached drawings. 1 is a diagrammatic perspective view of a particular embodiment of the wind turbine of the present invention; FIG. 2 schematically and in perspective shows a particular embodiment of the wind turbine; 3 schematically and top view, a particular embodiment of the wind turbine object of the present invention, Figure 4 shows, schematically and in perspective, a particular embodiment of the invention. 5 of the present invention, schematically and in perspective, a particular embodiment of FIG. the wind turbine which is the subject of the present invention, FIG. 6 schematically and top view shows a particular embodiment of the wind turbine which is the subject of the present invention and FIG. 7 is a diagrammatic sectional view of a particular embodiment. of the wind turbine of the present invention.

DESCRIPTION OF EXAMPLES OF THE INVENTION The present description is given in a nonlimiting manner, the characteristics of each embodiment being able to be combined in advantageous ways. It is noted that the figures are not to scale.

FIG. 1, which is not to scale, shows a perspective view of one embodiment of the wind turbine 10 which is the subject of the present invention. This wind turbine 10 comprises: a first shaft 105, called "hollow shaft", driving a generatrix 110, free in rotation and traversed by an opening 115, 25 a second shaft 120, called "solid shaft", positioned at least partially in the opening 115, fixed in rotation to the hollow shaft 105, and free in translation in this opening 115, at least one third shaft 125, called "support shaft", fixed to the solid shaft 120 along a radial axis and at least partially free in rotation about a longitudinal axis of said support shaft 125, the longitudinal axis being perpendicular to the axis of rotation of the first and second shafts, 105 and 120, 3033369 6 at least one blade 130, each blade 130 being secured to a support shaft 125, said blade 130 having a main axis parallel to the plane defined by the axes of rotation of the first, second and third shafts, 105, 120 and 125, and outside said plane, so that the main axis of the blade 130 s e approaches 5 of said plane when the wind force increases, at least one means 135 for mechanical drive of at least one support shaft 125 from a first position, in which the main axis of at least one blade 130 is close of the plane, at a second position, in which the main axis of each said blade 130 is remote from said plane, by rotation of the support shaft 125, a lever 145, comprising a roller 150, fixed to at least one shaft 125 of support, set in motion by the rotation of said support shaft 125 from a position, called "rest", to a position, called "folding", this movement causing a displacement in translation of the shaft 120 full to the opening 115 of the hollow shaft 105, two plates 140, fixed to the solid shaft, surrounding each roller 150 so as to allow the rolling of each roller 150, in particular to achieve the synchronization of the blades 130 together, a means 155 mechanical locking of positioning at least one support shaft 130 depending on the rotational movement of said support shaft 125, means 110 for generating electricity from the rotary motion of the hollow shaft 105. The wind turbine 10 is for example, a wind turbine with a horizontal axis of rotation 25 corresponding to the hollow shaft 105. The hollow shaft 105 is, for example, a hollow metal tube of circular cross section. In variants, the hollow shaft 105 is made of a synthetic material, such as a type of plastic for example. This hollow shaft 105 has an opening, not shown, passing through the shaft in the direction of the length of the tube, that is to say along a longitudinal axis. The hollow shaft 105 is fixed to a support, not shown, by two bearings 107 guiding the hollow shaft 105 in rotation. These bearings 107 are fixed to the plate by screwing, nailing or welding, for example. The plate may be fixed or free to rotate about an axis perpendicular to the axis of rotation of the hollow shaft 105. This plate is fixed to the ground or to a roof, for example, by means of a free mat in rotation or not. In variants, the wind turbine 10 comprises a single bearing 107 or no bearing 107, the assembly then being supported by the shaft of a generator 110, which is the case for the majority of small power wind turbines existing. The hollow shaft 105 drives a generator 110 of electric current as a function of the speed of rotation of this hollow shaft 105. This generator 110 is, for example, a dynamo whose function is to convert the mechanical energy of the rotation of the rotor. hollow shaft 105 in electrical energy. This generator is not limited to generating an electric current and can be implemented for any type of function requiring a rotary movement to be implemented. The hollow shaft 105 has at one end near the plate 140 a flared opening. In variants, this opening is surrounded by the circular plane surface 109. The hollow shaft 105 and the solid shaft 120 are fixed to each other by rods, not shown, passing through the two shafts, 105 and 120, so that the rotation of a shaft causes rotation from the other tree. The solid shaft 120 is, for example, a solid tube of circular cross section whose diameter corresponds to the diameter of the opening (not shown) of the hollow shaft 105. The solid shaft 120 is shorter than the opening of the hollow shaft 105 and is supported on a spring, corresponding for example to the mechanical drive means, bearing on a stop 122. The stop 122 is positioned and fixed on the rear side of the hollow shaft 105, c This is close to the generator 110 and / or remote from the blades 130. The spring corresponds to the mechanical drive means 135, for example. The whole spring-shaft assembly having a diameter similar to that of the opening of the hollow shaft 105, any translational movement of the solid shaft 120 is first slowed by the action of the spring and then stopped when the spring no longer has compression capability.

The spring is at rest when each support shaft 125 is at rest and deformed when each support shaft 125 is in a retracted position.

The solid shaft 120 is fixed, on the front side, that is to say on the side opposite to the abutment 122 and / or near the blades 130, to a first plate 140. This plate 140 is, for example, a planar surface in the form of star-shaped polygon with central symmetry, this star shape having as many points as the wind turbine 10 comprises blades 130, each point being formed by two segments of the polygon of different sizes. The length of the large segment is generally greater than or equal to the length of the lever 145 whose roller 150 is in contact with the part of the plate 140 closest to the segment. In variants, these segments are perpendicular to each other. In variants, the plate 140 has a shape having an odd plurality of blades 130 arranged in a central symmetry with respect to the center of the plate 140. In embodiments, the wind turbine 10 has a hydraulic damper positioned in the opposite direction. of the mechanical drive means 135, coaxially with the shaft 120, a fixed part and the body of the damper being fixed to a third plate which closes the assembly and ensures its sealing, the moving part of the damper being fixed to the shaft 120. This third plate, fixed to the plate 109 also prevents the assembly, formed by the shaft 120 and the plate 140, out of the opening of the hollow shaft 105 and limits therefore the race of this set by abutting against this third plateau. In the other direction of movement of the shaft 120, it is the other plate 140 which acts as a stop preventing at the end of the solid shaft 120 fixed to said plate 140 from entering the hollow shaft 105. This plate 140 is fixed to a second plate, not shown, by a set of protuberances 142 spacing the two plates by a distance equal to the diameter of the rollers 150 so that these rollers 150 roll between the plates during a rotation of the levers 145. Preferably, the wind turbine 10 comprises as many protuberances 142 as blades 130. These protuberances 142 have a hollow truncated revolution cylinder shape 30 for screwing the plate, not shown, to the protrusion 142. Preferably, a portion of the protuberances 142 is hollow and another part has secondary protuberances 144, longer than the protuberances 142 and having a smaller diameter. These secondary protuberances 144 are configured to be inserted into openings of dimensions similar to the cross section of said secondary protuberances 144. These secondary protuberances 144 are hollow so as to allow the attachment of a third plate, not shown, completely masking The levers 5 145. This masking makes it possible to limit the risk of injury and wear of the masked elements due to particles transported by the wind. These protuberances 144 are also fixed to the plate 109, these protuberances 144 causing the joint rotation of the hollow shaft 105 and the solid shaft 120 and the plate 109. Supporting protuberances 111 of the support shafts 125 are positioned on the periphery of the surface 109 surrounding the opening, not shown, of the hollow shaft 105 on the side of the blades 130. These support protuberances 111 are made of rigid material, in the same way as the flat surface 109. The wind turbine 10 comprises as many support protrusions 111 as support shafts 125. These support protuberances 111 are positioned so that the centers of gravity of these support protrusions 111 form a regular polygon, having as a center a point on the axis of rotation of the solid shaft 120 and the hollow shaft 105, perpendicular to this axis, the spacing between each support protrusion 111 being identical. At least one support protrusion 111 comprises two bearings, not shown, guiding the rotationally associated support shaft 125 by preventing a translation of said support shaft 125. In variants, these bearings are replaced by ball bearings. In variants, at least one support protrusion 111 has an aperture, not shown, circular shaped to receive an end of the associated support shaft 125. The openings, not shown, of these support protuberances 111 have a length sufficient to limit the risk of cracking of at least one support protrusion 111 under the action of a gust of wind. This length is determined by the person skilled in the art as a function of the material used to make the support protrusion 111 and by the exercise of a force, comparable to the force of a gust of wind, on the blade 130 associated with the support shaft 125 entering the opening. Each support shaft 125 is, for example, a tube or a cylindrical axis of circular cross section of rigid material. Each support shaft 125 is attached to one end of a lever 145 so that rotation of the support shaft 125 causes the trays to move toward the hollow shaft 105 or move the trays away from the housing. hollow shaft 105 according to the direction of rotation. In a rest position, the rest shafts 125 are positioned so that the plate 140 5 is spaced from the flat surface 109 of the hollow shaft 105. A blade 130 is fixed to each support shaft 125, this blade 130 having an opening, not shown, for the insertion of the support shaft 125. The main axis of each blade 130 is parallel and offset with respect to the axis of rotation of the support shaft 125 associated with this 130. In a resting position, the main axis of each blade 130 is parallel and outside the plane formed by the axes of rotation of the hollow shaft 105 and the support 125. Each blade 130 is made of sheet metal. OR aluminum, of plastic or other synthetic material, for example. Whatever the shape of these blades 130, these blades 130 are mounted on their axis of rotation in a manner sufficiently offset to rotate: under the wind pressure and / or under the centrifugal force associated with the rotation of the propeller . In preferred embodiments, the wind turbine 10 has six blades 130 to bring the wind turbine yield 10 closer to the Betz limit. The number of blades 130 may also depend on the diameter of the helix, the larger the helix, the greater the number of blades 130. The blades 130 are synchronized angularly by the play of the rollers 150, trays 140 and levers 145, each blade 130 contributing to a setback position or in a rest position of each other blade 130.

The wind turbine 10 further comprises a mechanical locking means (not shown) for the positioning of a support shaft 125, this locking blocking in position the solid shaft 120 with respect to the hollow shaft 105 when the rotation of a support shaft 125 has traveled a determined angle of rotation. This determined angle of rotation corresponds, for example, to 90% or more of the maximum possible rotation.

This locking means (not shown) is, for example, a stop or a non-return device removable by a user. Preferably, this locking means (not shown) is a hook catching a protuberance (not shown) of the solid shaft 120 when the full shaft 120 passes a certain position in the hollow shaft 105 during a displacement caused by the rotation of the blades 130 and from an extreme folding position of the blades 130 generated by a wind force that can damage the wind turbine 10.

This mechanical locking means (not shown) is illustrated in FIG. 7. Thus, as is understood from reading the present description, the action of the spring on the stop 122 causes the plate 140 to push to move this plate away. 140 of the flat surface 109 which, by the action of the levers 145, causes a rotation of the support shafts 125 and therefore of the blades 130 so that the blades 130 have the largest possible area in a direction perpendicular to the direction wind to generate, by the rotation of the hollow shaft 105, a maximum of mechanical and / or electrical energy. Conversely, when the wind force exceeds a certain value, the blades 130 cause rotation of the support shafts 125 due to the misalignment between the main axis of the blades 130 and the axes of rotation of the support shafts 125. This rotation causes the levers 145 which mechanically pull the trays 140 towards the surface of the support 109, the solid shaft 120 is then moved until the spring 135 prevents further movement. In case of excessive wind speed, the support shafts 125 are locked in position. Between the extreme cases where the blades 130 have either a maximum surface area or a minimum wind-holding area, the wind turbine 10 object of the present invention varies this surface as a function of the force exerted by the wind so as to perform a function variable pitch depending on the wind force.

These particular features allow a high reactivity of the wind turbine 10 so as to smooth the large variations in the wind force applied to the wind turbine 10 without using any force other than the mechanical force of the wind. These features further enable the wind turbine 10 to have rated power achieved at a low wind speed and that this power varies little with increasing wind speed. FIG. 2 shows a zoomed view of the wind turbine 10 in a retracted position, ie when the spring is compressed. In this position, the blades 130 are almost in the direction of the wind and the hollow shaft rotates at a similar speed to the speed of rotation observed when the wind turbine 10 is in the rest position and from a speed of wind at which the system begins to regulate the rotation regime. FIG. 3 shows a profile view of the wind turbine 10 in a folded position. It is observed, in particular, that the blades 130 have a minimum surface in the direction of the wind. FIG. 4 shows a perspective view of the wind turbine 10 in the rest position, that is to say when the spring is at rest. In this position, the blades 130 are the most sensitive to the force of the wind.

FIG. 5 shows a zoomed view of the wind turbine 10 in the rest position in which the plate 140 is remote from the flat surface 109. FIG. 6 shows a profile view of the wind turbine 10. wind turbine 10 in the rest position. FIG. 7 shows a sectional view of the wind turbine 10. In particular, it can be observed that the solid shaft 120 bears on a spring 135, this spring acting as a mechanical drive means. This spring 135 bears against a stop 122 so that the solid shaft assembly 120, spring 135 and stop 122 are positioned in the hollow shaft successively along the axis of rotation of this hollow shaft.

FIG. 8 shows a perspective view of a wind turbine 20 similar to the wind turbine 10 described with reference to FIGS. 1 to 7, which furthermore comprises at least one flyweight 170. Preferably, the wind turbine 20 comprises a counterweight per blade 130. Each counterweight 170 is, for example, a cylinder of full revolution in heavy material, such as metal for example. Each flyweight 170 is associated with a support shaft 125 and / or a blade 130 so that, when the blade 130 rotates, the support shaft 125 is more easily rotated due to the action of the force. centrifugal. In this version with flyweights, the angle in the rest position between each flyweight and the plane of the shafts 125 is 45 °, this angle may be greater.

Claims (7)

REVENDICATIONS1. Wind turbine (10), characterized in that it comprises: a first shaft (105), said "hollow shaft", driving a generatrix (110), free in rotation and traversed by an opening (115), a second shaft (120) ), said "solid shaft", positioned at least partially in the opening, fixed in rotation to the hollow shaft, and free in translation in this opening, at least a third shaft (125), called "support shaft", fixed to the solid shaft along a radial axis and at least partially free in rotation about a longitudinal axis of said support shaft, the longitudinal axis being perpendicular to the axis of rotation of the first and second shafts and at least one blade (130), each blade being integral with a support shaft, said blade having a main axis parallel to the plane defined by the axes of rotation of the first, second and third shafts and outside said plane, so that the main axis of the blade is approaching the plane when the force e wind increases. 2. Wind turbine (10) according to claim 1, which comprises at least one means (135) 20 mechanical drive of at least one support shaft (125) from a first position, wherein the main axis of at at least one blade (130) is close to the plane, at a second position, in which the main axis of each said blade is remote from said plane, by rotation of the support shaft. 25 3. Wind turbine (10) according to one of claims 1 or 2, wherein: the hollow shaft (105) comprises, at one end close to each support shaft (125), a plate (109) surrounding at least partially the opening (115) and at least one support shaft is fixed to the plate by at least one bearing. 30 4. Wind turbine (10) according to one of claims 1 to 3, which comprises: - a lever (145), comprising a roller (150), fixed to at least one support shaft (125), set in motion by the rotation of said support shaft from a position, said "rest", to a position, called "folding", this movement causing a displacement in translation of the shaft (120) to the full opening (115) of the hollow shaft (105) and two trays (140), attached to the solid shaft, surrounding each roller so as to allow the rolling of each roller to synchronize the rotation of the blades (130). 5. Wind turbine (10) according to claims 2 and 4, wherein the means (135) of mechanical drive is a spring, attached to the shaft (105) and the hollow shaft (120), being: - at rest when each support shaft (125) is at rest and - deformed when each support shaft is in a retracted position. Wind turbine (10) according to one of Claims 1 to 5, in which the hollow shaft (105) and the solid shaft (120) are connected in rotation to one another by means of protuberances (144). crossing the two trees. 7. Wind turbine (10) according to one of claims 1 to 6, which comprises means (110) for generating electricity from the rotary movement of the hollow shaft (105).