Propeller and vehicle provided with such a propeller

Abstract

The present invention relates to a propeller (5), preferably for hydrodynamic propulsion, comprising a hub (7) rotating about an axis of rotation (X), from which hub (7) at least three blades (9) extend, wherein the blades (9) are angularly evenly distributed from the hub (7) about the axis of rotation (X), and wherein the propeller (5) is characterised in that the blades (9) are axially offset along the axis of rotation (X) relative to one another. The invention also relates to a vehicle, preferably a marine vehicle, more preferably a ship, comprising such a propeller (5), and to a motor configured to drive the propeller (5), wherein the motor is preferably an electric motor.

Description

[0001] Propeller and vehicle equipped with such a propeller

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a propeller, preferably for hydrodynamic propulsion, as well as to a vehicle, preferably a marine vehicle, more preferably a ship, provided with such a propeller.

[0004] STATE OF THE ART

[0005] Most propellers currently available on the market are multi-blade propellers, comprising a hub pivoting around an axis of rotation, from which the blades extend radially. The blades are located on the hub and are angularly regularly distributed on the hub around this axis of rotation.

[0006] 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.

[0007] 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 generally a convex face, and an overpressure on the intrados face, which is generally a concave face. The water is then ejected, thus creating thrust.

[0008] Document US 3,266,578 discloses in particular a propeller driven by a motor, comprising a plurality of blades, at least a portion of which are inclined relative to the hub.

[0009] Document FR 2 567 844 A1 discloses in particular a propulsion device comprising several single-blade propellers offset longitudinally on the same axis, and whose dimensions are decreasing.

[0010] Document US 4,514,146 discloses in particular a propulsion propeller comprising four or more blades, at least two adjacent blades being inclined at angles of attack oriented respectively forward and backward, and the pitch angle of the backward inclined blade being greater than that of the forward inclined blade. However, most of the available propellers do not offer optimal efficiency, so they require the use of powerful motors, which cause high energy consumption.

[0011] Thus, particularly in liquid environments, most available propellers have turbulence problems, which are due in particular to hydrodynamic disturbances generated by the hub, as well as to the "recoil" caused in particular by the mutual influence of the blades on each other.

[0012] Thus, for most existing propellers, the rotation of the propeller causes turbulence that can disrupt the flow of water, which reduces the efficiency of the propeller, causes vibrations and noise.

[0013] STATEMENT OF THE INVENTION

[0014] The present invention aims to overcome all or part of the drawbacks cited above.

[0015] The invention aims in particular to provide a propeller with improved performance, while generating less vibration and noise.

[0016] According to a first aspect, the invention provides a propeller, preferably for hydrodynamic propulsion, comprising a hub pivoting about an axis of rotation, from which hub at least three blades extend, the blades being angularly regularly distributed from the hub about the axis of rotation, the propeller being remarkable in that the blades are axially offset along the axis of rotation relative to each other.

[0017] Thus, such a propeller has improved efficiency while generating less vibration and noise. More specifically, the use of at least three axially offset blades allows for better circulation of the fluid through the propeller as the propeller rotates around the axis of rotation. Indeed, the axial distance of each blade from the other blades reduces the disturbances generated by the hub, in particular hydrodynamic disturbances, as well as the propeller's recoil coefficient. For example, when the propeller is a pusher propeller, each blade pushes the fluid back without causing negative pressure or overpressure that would be detrimental to the thrust.

[0018] 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: - Each blade is capable of rotating along a rotation plane orthogonal to the rotation axis. Thus, each point of the blade is capable of rotating along a rotation plane orthogonal to the rotation axis.

[0019] - Each blade is axially offset at any point relative to an angularly adjacent blade.

[0020] - The longitudinal axis of each blade is orthogonal to the axis of rotation.

[0021] - The blades extend radially outward from the hub, relative to the axis of rotation.

[0022] - The propeller has exactly three, four, five, or six blades. Using this number of blades is optimal for hydrodynamic propulsion, especially for marine vehicles such as ships.

[0023] - Each blade comprises a blade profile comprising a leading edge and a trailing edge delimiting between them an intrados face and an extrados face.

[0024] - The angularly regularly distributed blades are arranged every 360° / Z around the axis of rotation, with Z the number of propeller blades.

[0025] - Each blade is axially offset by a predetermined axial distance from an angularly adjacent blade. Such a predetermined axial distance makes it possible to optimize the reduction of propeller disturbances while limiting propeller vibrations.

[0026] - The predetermined axial distance is identical for all blades. Thus, each blade is axially offset by the same predetermined axial distance from an angularly adjacent blade.

[0027] - The predetermined axial distance is at least equal to the thickness of the blade at its center. Thus, the reduction of disturbances is optimized.

[0028] - The center of the blade is defined as the middle of the blade's center chord.

[0029] - Each blade is connected to the hub by a blade root, the blade root being separated from each of the blade roots of the two blades angularly adjacent to the blade by a predetermined projection distance, the predetermined projection distance being considered on a projection plane orthogonal to the axis of rotation. Such a predetermined projection distance thus makes it possible to generate a passage for the fluid within the propeller allowing axial flow, which further reduces disturbances.

[0030] - The predetermined projection distance is identical for all blades. Thus, the blade root of each blade is separated from each of the blade roots of the two blades angularly adjacent to the blade by the same predetermined projection distance.

[0031] - Each blade is separated from the other blades by at least the predetermined projection distance, the predetermined projection distance being considered on a projection plane orthogonal to the axis of rotation. Thus, a passage for the fluid is allowed axially between each blade, which further reduces disturbances.

[0032] - For each blade, the predetermined projection distance is less than or equal to the projection width of the blade root of the blade, the projection width being considered on a projection plane orthogonal to the axis of rotation, the projection distance preferably being equal to the thickness of the blade. Such a predetermined projection distance thus makes it possible to optimize the reduction of disturbances while maximizing the efficiency of the propeller.

[0033] - The blades are identical. This reduces vibrations and improves propeller efficiency.

[0034] - The blades have the same pitch angle. This reduces disturbances and vibrations, while improving the propeller's efficiency.

[0035] - Each blade has a pitch angle offset by the same angular value, preferably between 5° and 10°, more preferably equal to 5°, relative to an angularly adjacent blade.

[0036] - Each blade has a pitch angle between 15° and 45°, preferably between 30° and 45°.

[0037] - The blades have a fixed pitch. This simplifies the operation of the propeller.

[0038] - The blades have variable pitch. This makes it possible to further optimize the propeller's efficiency.

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

[0040] - The propeller is monolithic. This optimizes the structural integrity of the propeller and simplifies its manufacturing. - The propeller is made of plastic, metal, or wood, for example, bronze, or a fiber-reinforced polymer composite material, the fibers being, for example, glass or carbon fibers. The use of such materials allows the propeller material to be adapted to its intended use. For example, a bronze propeller is particularly suitable for mounting on a large-tonnage vessel such as a cargo ship, a container ship, a supertanker, or an LNG carrier.

[0041] According to a second 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.

[0042] 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.

[0043] 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:

[0045] - figure 1 is a schematic side view of a ship comprising a propeller according to one embodiment;

[0046] - figure 2 is a side view of a propeller according to one embodiment;

[0047] - Figure 3 is another side view of the propeller shown in Figure 2, in which the propeller is in another angular position of rotation about its axis of rotation;

[0048] - figure 4 schematically represents a propeller according to an alternative embodiment, in projection on a projection plane orthogonal to the axis of rotation of the propeller.

[0049] Throughout the figures, similar elements are designated by identical references.

[0050] DETAILED DESCRIPTION OF THE INVENTION

[0051] Figure 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.

[0052] Vehicle 1 has an engine 3 and a propeller 5.

[0053] Motor 3 is configured to drive propeller 5. Preferably, motor 3 is an electric motor.

[0054] 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.

[0055] Figure 2 and Figure 3 show an embodiment of a propeller 5.

[0056] Advantageously, the propeller 5 is monolithic. The propeller 5 is thus formed from a single block, in a single piece.

[0057] 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.

[0058] Advantageously, the propeller 5 comprises a hub 7 from which at least three 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.

[0059] Advantageously, the axis of the motor shaft 3 coincides with the axis of rotation X.

[0060] Preferably, the hub 7 is cylindrical.

[0061] According to the variant shown in Figure 2 and Figure 3, the propeller 5 comprises exactly three blades 9. Alternatively, according to variants not shown, the propeller 5 comprises exactly four, five or six blades 9.

[0062] Preferably, the blades 9 are identical.

[0063] Advantageously, each blade 9 comprises a blade profile comprising a leading edge and a trailing edge delimiting between them an intrados face and an extrados face.

[0064] Advantageously, the blades 9 have the same pitch angle a. Alternatively and according to a variant not shown, each blade 9 has a pitch angle a offset by the same angular value, preferably between 5° and 10°, more preferably equal to 5°, relative to an angularly adjacent blade 9. For example, in the case of a propeller 5 comprising exactly four blades 9, the first blade 9, preferably the blade 9 upstream on the hub 7, has a pitch angle of 30°, the second blade 9 adjacent to the first blade 9, axially closest to the first blade 9, has a pitch angle of 35°, the third blade 9 adjacent to the second blade 9 has a pitch angle of 40°, and the fourth blade 9 adjacent to the third blade 9 has a pitch angle of 45°.

[0065] Preferably, each blade 9 has a pitch angle of between 15° and 45°, preferably between 30° and 45°.

[0066] Preferably, the blades 9 have a fixed pitch. Alternatively, according to a variant not shown, the blades have a variable pitch. Advantageously, according to this variant not shown, the blades are pivotally attached to the hub, each blade being configured to pivot selectively about a longitudinal axis of the blade in order to adjust the pitch of the blade.

[0067] Preferably, the longitudinal axis of the blade 9 is orthogonal to the axis of rotation X. In other words, for each blade 9, the longitudinal axis of the blade 9 is orthogonal to the axis of rotation X. Thus, the longitudinal axis of each blade 9 is orthogonal to the axis of rotation X.

[0068] Advantageously, each blade 9 is capable of rotating along a rotation plane orthogonal to the rotation axis X.

[0069] Preferably, each blade 9 is axially offset at any point relative to an angularly adjacent blade 9.

[0070] 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.

[0071] Thus, according to the embodiment shown in Figure 2 and Figure 3, the propeller 5 comprises three blades 9, Z is therefore 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, one blade 9 is arranged at 120°, one blade 9 is arranged at 240°, and one blade 9 is arranged at 360°. 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.

[0072] Preferably, the blades 9 extend radially outward from the hub 7, relative to the axis of rotation X.

[0073] Advantageously, the blades 9 are axially offset along the axis of rotation X relative to each other.

[0074] Preferably, each blade 9 is axially offset by a predetermined axial distance Dx relative to an angularly adjacent blade 9.

[0075] Advantageously, the predetermined axial distance Dx is identical for all the blades 9. In other words, each blade 9 is axially offset by the same predetermined axial distance Dx relative to an angularly adjacent blade 9.

[0076] Advantageously, the predetermined axial distance Dx is at least equal to the thickness E of the blade 9 at its center C.

[0077] Preferably, as shown in Figure 2 and Figure 3, the predetermined axial distance Dx is equal to the thickness E of the blade 9 at its center C.

[0078] Advantageously, the center C of the blade 9 is defined as the middle of the middle chord of the blade 9.

[0079] Preferably, each blade 9 is connected to the hub 7 by a blade root 11. Advantageously, the blade root 11 is separated from each of the blade roots 11 of the two blades 9 angularly adjacent to the blade 9 by a predetermined projection distance Dp.

[0080] Preferably, the predetermined projection distance Dp is considered on a projection plane P orthogonal to the rotation axis X, as is notably represented in Figure 3.

[0081] Advantageously, the predetermined projection distance Dp is identical for all the blades 9. Thus, the blade root 11 of each blade 9 is separated from each of the blade roots 11 of the two blades 9 angularly adjacent to the blade 9 by the same predetermined projection distance Dp.

[0082] Preferably, each blade 9 is separated from the other blades 9 by at least the predetermined projection distance Dp. Advantageously, for each blade 9, the predetermined projection distance Dp is less than or equal to a projection width Lp of the blade root 11 of the blade 9, the projection width Lp being considered on the projection plane P orthogonal to the axis of rotation X.

[0083] Preferably, as shown in Figure 3, the projection distance Dp is equal to the thickness E of the blade 9.

[0084] Advantageously, the predetermined projection distance Dp is equal to the predetermined axial distance Dx. Thus, a passage for the fluid is allowed axially between each blade 9, while limiting the dimensions of the hub 7.

[0085] 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.

[0086] Figure 4 schematically represents an alternative embodiment of the propeller 5, in projection onto the projection plane P orthogonal to the axis of rotation X of the propeller 5. The propeller 5 according to this alternative embodiment differs from the propeller 5 previously described and represented in particular in Figure 3 in that, for each blade 9, the predetermined projection distance Dp is equal to the projection width Lp of the blade root 11 of the blade 9.

[0087] More generally, the propeller 5 previously described can be configured to be mounted on a hydraulic turbine, a hydro turbine, a wind turbine, a turbomachine.

[0088] 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. Propeller (5), preferably for hydrodynamic propulsion, comprising a hub (7) pivoting about an axis of rotation (X), hub (7) from which at least three blades (9) extend, the blades (9) being angularly regularly distributed from the hub (7) about the axis of rotation (X), characterized in that the blades (9) are identical and in that each blade (9) is axially offset by the same predetermined axial distance (Dx) relative to an angularly adjacent blade (9).

2. Propeller (5) according to claim 1, in which each blade (9) is capable of rotating along a plane of rotation orthogonal to the axis of rotation (X).

3. Propeller (5) according to claim 1 or 2, in which the longitudinal axis of each blade (9) is orthogonal to the axis of rotation (X).

4. Propeller (5) according to one of claims 1 to 3, in which each blade (9) is axially offset at any point relative to an angularly adjacent blade (9).

5. Propeller (5) according to one of claims 1 to 4, in which the predetermined axial distance (Dx) is at least equal to the thickness (E) of the blade (9) at its center.

6. Propeller (5) according to one of claims 1 to 5, in which each blade (9) is connected to the hub (7) by a blade root (11), the blade root (11) being separated from each of the blade roots (11) of the two blades (9) angularly adjacent to the blade (9) by a predetermined projection distance (Dp), the predetermined projection distance (Dp) being considered on a projection plane (P) orthogonal to the axis of rotation (X).

7. Propeller (5) according to claim 6, in which for each blade (9), the predetermined projection distance (Dp) is less than or equal to the projection width (Lp) of the blade root (11) of the blade (9), the projection width (Lp) being considered on a projection plane (P) orthogonal to the axis of rotation (X), the projection distance (Dp) preferably being equal to the thickness (E) of the blade (9) at its center.

8. Propeller (5) according to one of claims 1 to 7, in which the blades (9) have the same pitch angle (a).

9. Propeller (5) according to one of claims 1 to 7, in which each blade (9) has a pitch angle (a) offset by the same angular value, preferably between 5° and 10°, more preferably equal to 5°, relative to an angularly adjacent blade (9).

10. Propeller (5) according to one of claims 1 to 9, in which the hub (7) is cylindrical.

11. Propeller (5) according to one of claims 1 to 10, which is monolithic.

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

Images