Propeller blade, propeller and vehicle equipped with such a propeller

Abstract

The present invention relates to a blade (9) for a propeller (5), formed by at least three sections (23a, 23b, 23c) extending successively directly one after the other from a first end (E1) of the blade (9) forming a blade root to a second end (E2) of the blade (9) forming a blade tip, the pitch angle of each section (23b, 23c) directly following a preceding section (23a, 23b) being at least 5 degrees lower than the pitch angle of the preceding section (23a, 23b). The invention also relates to a propeller (5) comprising at least two such blades (9), as well as to a vehicle, preferably a marine vehicle, more preferably a ship, comprising such a propeller (5) and a motor configured to drive the propeller (5), the motor preferably being an electric motor. Figure for abstract: Fig. 2

Description

Title of the invention: Propeller blade, propeller and vehicle equipped with such a propeller FIELD OF THE INVENTION

[0001] The present invention relates to a blade for a propeller, preferably for a propeller for hydrodynamic propulsion. The present invention also relates to a propeller, preferably for hydrodynamic propulsion, provided with at least two such blades. The invention finally relates to a vehicle, preferably a marine vehicle, more preferably a ship, provided with such a propeller. STATE OF THE ART

[0002] Most propellers currently available on the market are multi-bladed propellers, comprising a hub pivoting about an axis of rotation, from which hub the blades extend radially. The blades are located on the hub and are angularly regularly distributed on the hub about this axis of rotation.

[0003] A propeller can thus be a driving propeller, for example mounted on a vehicle such as a boat or an aircraft, or a receiving propeller, for example mounted on a turbine, a wind turbine or a wind generator.

[0004] The shape of the blades of existing propellers, which are generally arranged relative to each other according to the screw principle when they are intended for use in water, creates a depression on the extrados face, which is a generally convex face, and an overpressure on the intrados face, which is a generally concave face. The water is then ejected, thus creating thrust.

[0005] However, most of the available propellers do not offer optimal performance, so they require the use of powerful motors, which cause high energy consumption.

[0006] Thus, particularly in a liquid medium, most of the available propellers have turbulence problems, which are notably due to the hydrodynamic disturbances generated by the blades, as well as to the “recoil” notably caused by the mutual influence of the blades on each other.

[0007] Thus, for most existing propellers, the rotation of the propeller causes turbulence which can disturb the flow of water, which reduces the efficiency of the propeller, causes vibrations and noise. Statement of the invention

[0008] The present invention aims to overcome all or part of the drawbacks cited above.

[0009] The invention aims in particular to provide a propeller blade whose efficiency is improved, while generating less vibration and noise.

[0010] According to a first aspect, the invention proposes a blade for a propeller, preferably for a propeller for hydrodynamic propulsion, remarkable in that it is formed by at least three sections extending successively directly one after the other from a first end of the blade forming a blade root to a second end of the blade forming a blade tip, the pitch angle of each section directly following a preceding section being at least 5 degrees lower than the pitch angle of the preceding section.

[0011] Thus, such a propeller blade makes it possible to reduce the disturbances generated by the latter, which allows the propeller equipped with such blades to have improved efficiency while generating less vibration and noise. More precisely, the use of at least three sections equipped with such pitch angles offset relatively to each other makes it possible to reduce the disturbances generated, in particular hydrodynamic disturbances.

[0012] By "section directly following a preceding section", it is meant a section directly following a preceding section in the direction going from the first end of the blade forming the blade root towards the second end of the blade forming the blade tip. Thus, advantageously, these two sections are adjacent. Furthermore, advantageously, no transition element is in particular arranged between the section in question and the preceding section.

[0013] The blade according to the invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0014] - The blade is formed by exactly three sections. Thus, the design and the blade manufacturing are simplified.

[0015] - The sections extend successively directly one after the other following a leading edge of the blade.

[0016] - Each section has a predetermined setting angle. Thus, the design and blade manufacturing are simplified.

[0017] - All the setting angles are located in a single angular sector less than or equal to 45 degrees, preferably less than or equal to 35 degrees. This ensures optimal efficiency improvement.

[0018] - The setting angle of each section is defined relative to a rotation plane of the blade, in other words the plane of rotation of the propeller carrying the blade, the plane of rotation being orthogonal to the axis of rotation of the propeller.

[0019] - For each section directly following a preceding section, the setting angle of the section directly following the previous section is less than the setting angle of the previous section by a value between 5 degrees and 30 degrees, preferably by a value between 5 degrees and 20 degrees, more preferably by a value between 5 degrees and 15 degrees. Thus, the improvement in efficiency is optimal.

[0020] - For each section directly following a preceding section, the length minimum chord length of the section directly following the previous section differs by at least 10% from the maximum chord length of the previous section, preferably differs by at least 30% from the maximum chord length of the previous section. Thus, the disturbances generated by the blade are reduced, while maintaining improved efficiency.

[0021] - The trailing edge is included in a plane, preferably in a plane comprising the axis of rotation and orthogonal to the plane of rotation, the plane of rotation itself being orthogonal to the axis of rotation. Thus, the design and manufacture of the blade are simplified.

[0022] - For each section directly following a preceding section, the length minimum chord length of the section directly following the previous section is at least 10% greater than the maximum chord length of the previous section, preferably at least 30% greater than the maximum length of the previous section. Thus, the disturbances generated by the blade are reduced, while maintaining improved efficiency.

[0023] - For each section directly following a preceding section, the thickness maximum thickness of the section directly following the previous section is at least 10% less than the maximum thickness of the previous section, preferably at least 20% less than the maximum thickness of the previous section. Thus, the mass of the blade is reduced.

[0024] - The sections are gradually offset from each other. Thus, the performance is improved.

[0025] - The blade has an intrados face and an extrados face extending between the edge leading edge and a trailing edge.

[0026] - For each section directly following a preceding section, the section directly following the preceding section is flush with the preceding section either only on the intrados side over a major part of the intrados face leading to the leading edge, or only on the extrados side over a major part of the extrados face leading to the leading edge. Thus, the disturbances generated by the blade are reduced, while maintaining improved efficiency.

[0027] - The leading edge is straight on each section, preferably is completely straight. Thus, the disturbances generated by the blade are reduced.

[0028] - Each section directly following a previous section is offset by an angle predetermined around a longitudinal axis of the blade relative to the previous section. Thus, manufacturing is simplified.

[0029] - The blade is monolithic. Thus, the structural integrity of the blade is optimized, and its manufacturing is simplified.

[0030] According to a second aspect, the invention proposes a propeller, preferably for hydrodynamic propulsion, comprising a hub pivoting around an axis of rotation, from which hub at least two blades as previously described extend, the blades being angularly regularly distributed from the hub around the axis of rotation.

[0031] Thus, such a propeller has improved efficiency while generating less vibration and noise. More specifically, the use of at least two blades as previously described allows for better circulation of the fluid through the propeller during rotation of the propeller around the axis of rotation. Indeed, the difference in pitch angle between the sections reduces the disturbances generated by the propeller, in particular hydrodynamic disturbances, as well as the recoil coefficient of the propeller. For example, when the propeller is a propulsive propeller, each blade pushes the fluid back without causing negative pressure or overpressure that is detrimental to the thrust.

[0032] The propeller according to the invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0033] - The blades extend radially outward from the hub, relative to the axis of rotation.

[0034] - The blades are angularly regularly distributed and are arranged every 360° / Z around the axis of rotation, with Z the number of propeller blades.

[0035] - The blades are identical. Thus, vibrations are reduced and the efficiency of the propeller is improved.

[0036] - The blades have a fixed pitch. This simplifies the operation of the propeller.

[0037] - The blades are variable pitch. Thus, it is possible to further optimize the propeller efficiency.

[0038] - The propeller comprises exactly three, four, five, six, seven or eight blades. The use of such a number of blades is optimal for hydrodynamic propulsion, particularly of marine vehicles such as ships.

[0039] - The hub is cylindrical. Thus, the disturbances of the hub on the blades are limited.

[0040] - The propeller is monolithic. Thus, the structural integrity of the propeller is optimized, and its manufacturing is simplified.

[0041] - The propeller is made of plastic, metal or wood, for example bronze or made of a composite material based on a polymer reinforced with fibers, the fibers being, for example, glass or carbon fibers. The use of such materials makes it possible to adapt the propeller material to its use. For example, a bronze propeller is particularly suitable for installation on a large tonnage vessel such as a cargo ship, a container ship, a supertanker or an LNG carrier.

[0042] According to a third aspect, the invention also provides a vehicle, preferably a marine vehicle, preferably a boat, more preferably a ship, comprising a propeller as previously described and a motor configured to drive the propeller, the motor preferably being an electric motor.

[0043] Indeed, the propeller according to the invention is particularly suitable for being mounted on a vehicle, preferably a marine vehicle such as a boat, in particular a ship. Preferably, the use of an electric motor makes it possible to reduce the noise as well as the vibrations transmitted to the propeller, and consequently makes it possible to reduce the vibrations of the propeller itself during its drive. DESCRIPTION OF FIGURES

[0044] Other characteristics, aims and advantages of the invention will emerge from the detailed description below, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings, given as non-limiting examples and in which: - [Fig.l] is a schematic side view of a vehicle comprising a propeller according to one embodiment; - [Fig.2] is a schematic front view of a propeller according to one embodiment; - [Fig.3] is a schematic top view of a blade of the propeller shown in [Fig.2]; - [Fig.4] is a schematic front view of a propeller according to a first variant embodiment; - [Fig.5] is a schematic top view of a blade of a propeller according to a second variant embodiment.

[0045] Throughout the figures, similar elements are designated by identical references. DETAILED DESCRIPTION OF THE INVENTION

[0046] [Fig. 1] schematically represents an embodiment of a vehicle 1, which is preferably a marine vehicle, preferably a boat, more preferably a ship. Alternatively, according to a variant not shown, the vehicle 1 may be an aerial vehicle such as an aircraft or a drone.

[0047] The vehicle 1 comprises an engine 3 and a propeller 5.

[0048] The motor 3 is configured to drive the propeller 5. Preferably, the motor 3 is an electric motor.

[0049] Preferably, the propeller 5 is a propeller for hydrodynamic propulsion. The propeller 5 is thus configured to be driven in rotation in the water by the motor 3.

[0050] Advantageously, the propeller 5 is monolithic. The propeller 5 is thus formed from a block, in a single piece.

[0051] Preferably, the propeller 5 is made of plastic, metal or wood. The propeller 5 is preferably made of bronze or a composite material based on a polymer reinforced with fibers. Advantageously, the fibers are glass or carbon fibers.

[0052] Advantageously, the propeller 5 comprises a hub 7 from which at least two blades 9 extend. Thus, the hub 7 supports the blades 9. The hub 7 pivots about an axis of rotation X. Thus, the propeller 5 also pivots about the axis of rotation X.

[0053] Advantageously, the axis of the shaft of the motor 3 coincides with the axis of rotation X.

[0054] Preferably, the hub 7 is cylindrical.

[0055] [Fig.2] schematically represents an embodiment of a propeller 5, in projection onto a plane of rotation P of the propeller 5, the plane of rotation P being orthogonal to the axis of rotation X of the propeller 5.

[0056] According to the embodiment shown in [Fig.2], the propeller 5 comprises exactly three blades 9. Alternatively, according to variants not shown, the propeller 5 comprises exactly four, five, six, seven or eight blades 9.

[0057] Advantageously, each blade 9 is monolithic.

[0058] Preferably, the blades 9 are identical.

[0059] Preferably, the blades 9 have a fixed pitch. Alternatively, according to a non-variant shown, the blades have variable pitch. Advantageously, according to this variant not shown, the blades are pivotally attached to the hub, each blade being configured to pivot selectively around a longitudinal axis of the blade in order to adjust the pitch of the blade.

[0060] Advantageously, the blades 9 are angularly regularly distributed from the hub 7 around the axis of rotation X. In other words, the angularly regularly distributed blades 9 are arranged every 360° / Z around the axis of rotation X, with Z the number of blades 9 of the propeller 5. In the embodiment shown in [Fig.2], the propeller 5 comprising three blades 9, Z is consequently equal to 3. The three blades 9 are arranged every 360° / 3 = 120° around the axis of rotation X. For example, in a rotation position of the propeller 5 around the axis of rotation X, a blade 9 is arranged at 120°, blade 9 is arranged at 240°, and blade 9 is arranged at 360°.

[0061] Similarly, according to the variants not shown in which the propeller 5 comprises four, five or six blades 9, when the propeller 5 comprises four blades 9, the four blades 9 are arranged every 90° around the axis of rotation X, when the propeller 5 comprises five blades 9, the five blades 9 are arranged every 72° around the axis of rotation X, and when the propeller comprises six blades 9, the six blades 9 are arranged every 60° around the axis of rotation X.

[0062] Preferably, the blades 9 extend radially outwards from the hub 7, relative to the axis of rotation X.

[0063] Advantageously, the hub 7 comprises a notch 13 extending radially on either side of the axis of rotation X. Such a notch 13 makes it possible to transmit torque simply and safely from the motor 5 to the hub 7, via a motor shaft. The motor shaft then comprises a rib complementary to the notch 13.

[0064] Advantageously, as shown in [Fig.2] and / or in [Fig.3], each blade 9 comprises a leading edge 15 and a trailing edge 17 delimiting between them an intrados face 19 and an extrados face 21.

[0065] Advantageously, each blade 9 is formed by a plurality of sections 23a, 23b, 23c extending successively directly one after the other from a first end E1 of the blade 9 forming a blade root to a second end E2 of the blade 9 forming a blade tip.

[0066] Preferably, each blade 9 is formed by at least three sections 23a, 23b, 23c extending successively directly one after the other from a first end E1 of the blade 9 forming a blade root to a second end E2 of the blade 9 forming a blade tip.

[0067] Preferably, the sections 23a, 23b, 23c extend along the leading edge 15 of the blade 9.

[0068] Advantageously, the intrados face 19 and / or the extrados face 21 may comprise one facet per section 23a, 23b, 23c. Preferably, the adjacent facets of the intrados face 19 and / or the adjacent facets of the extrados face are concurrent only at the leading edge 15.

[0069] Preferably, each blade 9 is formed by exactly three sections 23a, 23b, 23c.

[0070] Advantageously, the setting angle a2, a3 of each section 23b, 23c directly following a preceding section 23a, 23b is at least 5 degrees lower than the setting angle a1, a2 of the preceding section 23a, 23b.

[0071] Preferably, each section 23a, 23b, 23c has a predetermined setting angle a1, a2, a3.

[0072] Advantageously, all of the setting angles a1, a2, a3 are located in a single angular sector less than or equal to 45 degrees, preferably less than or equal to 35 degrees.

[0073] The pitch angle a1, a2, a3 of each section 23a, 23b, 23c is defined relative to a plane of rotation P of the blade 9, in other words the plane of rotation P of the propeller 5 carrying the blade 9, the plane of rotation P being orthogonal to the axis of rotation X of the propeller 5.

[0074] Advantageously, for each section 23b, 23c directly following a preceding section 23a, 23b, the setting angle a2, a3 of each section 23b, 23c directly following the preceding section 23a, 23b is less than the setting angle a1, a2 of the preceding section 23a, 23b by a value between 5 degrees and 30 degrees, preferably by a value between 5 degrees and 20 degrees, more preferably by a value between 5 degrees and 15 degrees.

[0075] For example, as shown in [Fig.3], the wedging angle a2 of the section 23b is 15 degrees less than the wedging angle a1 of the section 23a, and the wedging angle a3 of the section 23c is 5 degrees less than the wedging angle of the section 23b.

[0076] Advantageously, for each section 23b, 23c directly following a preceding section 23a, 23b, the minimum length of the chord of the section 23b, 23c directly following the preceding section 23a, 23b differs by at least 10% from the maximum length of the chord of the preceding section 23a, 23b, preferably differs by at least 30% from the maximum length of the chord of the preceding section 23a, 23b.

[0077] Preferably, for each section 23b, 23c directly following a preceding section 23a, 23b, the minimum length of the chord of the section 23b, 23c directly following the preceding section 23a, 23b is at least 10% greater than the maximum length of the chord of the preceding section 23a, 23b, preferably is at least 30% greater than the maximum length of the preceding section 23a, 23b.

[0078] Advantageously, for each section 23b, 23c directly following a preceding section 23a, 23b, the maximum thickness of the section 23b, 23c directly following the preceding section 23a, 23b is at least 10% less than the maximum thickness of the preceding section 23a, 23b, preferably is at least 20% less than the maximum thickness of the preceding section 23a, 23b.

[0079] Preferably, the sections 23a, 23b, 23c are gradually offset from each other.

[0080] Advantageously, the leading edge 15 is rectilinear on each section 23a, 23b, 23c.

[0081] [Fig.4] schematically represents a first variant embodiment of the propeller 5, in projection onto the plane of rotation P orthogonal to the axis of rotation X of the propeller 5.

[0082] The propeller 5 according to this first embodiment variant is distinguished from the propeller 5 previously described and represented in particular in [Fig.2] in the following.

[0083] Advantageously, as shown in [Fig.4], the leading edge 15 is completely rectilinear.

[0084] Preferably, each blade 9 is such that the adjacent sections 23a-23b, 23b-23c are flush with each other either only on the side of the intrados face 19 over a major part of the intrados face 19 leading to the leading edge 15, or only on the side of the extrados face 21 over a major part of the extrados face 21 leading to the leading edge 15.

[0085] In other words, for each section 23b, 23c directly following a preceding section 23a, 23b, the section 23b, 23c directly following the preceding section 23a, 23b is flush with the preceding section 23a, 23b either only on the side of the intrados face 19 over a major part of the intrados face 19 leading to the leading edge 15, or only on the side of the extrados face 21 over a major part of the extrados face 21 leading to the leading edge 15.

[0086] As shown in [Fig.4], the offset of the sections 23a, 23b, 23c relative to each other is thus achieved by an offset on the side of the intrados face 19. Thus, for each section 23b, 23c directly following a preceding section 23a, 23b, the section 23b, 23c directly following the preceding section 23a, 23b is flush with the preceding section 23a, 23b only on the side of the extrados face 21 over a major portion of the extrados face 21 leading to the leading edge 15.

[0087] Preferably, as shown in [Fig.4], the trailing edge 17 is included in a plane F, preferably in a plane F comprising the axis of rotation X and orthogonal to the plane of rotation P, the plane of rotation P itself being orthogonal to the axis of rotation X.

[0088] [Fig.5] schematically represents a top view of a blade 9 of a propeller 5 according to a second variant embodiment.

[0089] The propeller 5 according to this second embodiment variant is distinguished from the propeller 5 previously described and represented in particular in [Fig.2] in the following.

[0090] Advantageously, each blade 9 is formed by a plurality of sections 23a, 23b, 23c extending successively directly one after the other along the longitudinal axis L of the blade 9 from a first end E1 of the blade 9 forming a blade root to a second end E2 of the blade 9 forming a blade tip.

[0091] Preferably, each blade 9 is formed by at least three sections 23a, 23b, 23c extending successively directly one after the other along the longitudinal axis L of the blade 9 from a first end E1 of the blade 9 forming a blade root to a second end E2 of the blade 9 forming a blade tip.

[0092] Advantageously, the longitudinal axis L extends radially relative to the axis of rotation X.

[0093] Preferably, the longitudinal axis L is orthogonal to the axis of rotation X of the propeller 5 and is parallel to the plane of rotation P. More preferably, the longitudinal axis L extends orthogonally and radially relative to the axis of rotation X. In other words, the longitudinal axis L extends perpendicular to the axis of rotation X.

[0094] Advantageously according to this second embodiment variant, for each section 23b, 23c directly following a preceding section 23a, 23b, the setting angle a2, a3 of each section 23b, 23c directly following the preceding section 23a, 23b is less than the setting angle a1, a2 of the preceding section 23a, 23b by a value between 5 degrees and 30 degrees.

[0095] Advantageously, each section 23b, 23c directly following a preceding section 23a, 23b is offset by a predetermined angle around the longitudinal axis L of the blade 9 relative to the preceding section 23a, 23b.

[0096] Preferably, the sections 23a, 23b, 23c are aligned along the longitudinal axis L and have only a predetermined angular offset around the longitudinal axis L relative to each other.

[0097] Thus, according to this second embodiment variant, the section 23b is offset by an angle a2 - a1 around the longitudinal axis L relative to the section 23a, and the section 23c is offset by an angle a3 - a2 around the longitudinal axis L relative to the section 23a.

[0098] Advantageously, all of the setting angles a1, a2, a3 are located in a single angular sector less than or equal to 45 degrees.

[0099] For example, as shown in [Fig.5], the wedging angle al of the section 23a is equal to 13°, the wedging angle a2 of the section 23b is equal to 29°, and the wedging angle a3 of the section 23c is equal to 55°.

[0100] More generally, the blade 9 and / or the propeller 5 previously described can be configured to be mounted on a hydraulic turbine, a hydro turbine, a wind turbine, a turbomachine.

[0101] The invention is not limited to the embodiments and variants presented and other embodiments will become clear to those skilled in the art. It is in particular possible to combine the embodiments and variants with each other.

Claims

Claims

1. Blade (9) for a propeller (5), preferably for a propeller for hydrodynamic propulsion, characterized in that it is formed by at least three sections (23a, 23b, 23c) extending successively directly one after the other from a first end (El) of the blade (9) forming a blade root to a second end (E2) of the blade (9) forming a blade tip, the pitch angle a2, a3 of each section (23b, 23c) directly following a preceding section (23a, 23b) being at least 5 degrees lower than the pitch angle a1, a2 of the preceding section (23a, 23b).

2. Blade (9) according to claim 1, in which, for each section (23b, 23c) directly following a preceding section (23a, 23b), the pitch angle a2, a3 of the section (23b, 23c) directly following the preceding section (23a, 23b) is less than the pitch angle a1, a2 of the preceding section (23a, 23b) by a value between 5 degrees and 30 degrees.

3. A blade (9) according to claim 1 or 2, wherein, for each section (23b, 23c) directly following a preceding section (23a, 23b), the minimum length of the chord of the section (23b, 23c) directly following the preceding section (23a, 23b) differs by at least 10% from the maximum length of the chord of the preceding section (23a, 23b), preferably differs by at least 30% from the maximum length of the chord of the preceding section (23a, 23b).

4. Blade (9) according to claim 3, in which, for each section (23b, 23c) directly following a preceding section (23a, 23b), the minimum length of the chord of the section (23b, 23c) directly following the preceding section (23a, 23b) is at least 10% greater than the maximum length of the chord of the preceding section (23a, 23b).

5. Blade (9) according to any one of claims 1 to 4, wherein, for each section (23b, 23c) directly following a preceding section (23a, 23b), the maximum thickness of the section (23b, 23c) directly following the preceding section (23a, 23b) is at least 10% less than the maximum thickness of the preceding section (23a, 23b), preferably is at least 20% less than the maximum thickness of the preceding section (23a, 23b).

6. A blade (9) according to any one of claims 1 to 5, wherein the sections (23a, 23b, 23c) are gradually offset from each other.

7. A blade (9) according to any one of claims 1 to 6, which has a lower surface face (19) and an upper surface face (21) extending between the leading edge (15) and a trailing edge (17), and in which, for each section (23b, 23c) directly following a preceding section (23b, 23c), the section (23b, 23c) directly following the preceding section (23a, 23b, 23c) is flush with the preceding section (23b, 23c) either only on the side of the lower surface face (19) over a major portion of the lower surface face (19) leading to the leading edge (15), or only on the side of the upper surface face (21) over a major portion of the upper surface face (21) leading to the leading edge (15).

8. Blade (9) according to any one of claims 1 to 7, in which the leading edge (15) is rectilinear on each section (23a, 23b, 23c), preferably is completely rectilinear.

9. A blade (9) according to any one of claims 1 to 8, wherein each section (23b, 23c) directly following a preceding section (23a, 23b) is offset by a predetermined angle around a longitudinal axis (L) of the blade (9) relative to the preceding section (23a, 23b).

10. Propeller (5), preferably for hydrodynamic propulsion, comprising a hub (7) pivoting about an axis of rotation (X), hub (7) from which at least two blades (9) according to any one of claims 1 to 9 extend, the blades (9) being angularly regularly distributed from the hub (7) about the axis of rotation (X).

11. Vehicle (1), preferably marine vehicle, more preferably ship, comprising a propeller (5) according to claim 10 and a motor (3) configured to drive the propeller (5), the motor (3) preferably being an electric motor.

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