An annular propeller comprising blades at least partially made of fiber-reinforced polymer.

Abstract

This invention relates to an annular propeller comprising multiple blades, each blade being at least partially made of a fiber-reinforced polymer and having an end and a root. A tenon is disposed at the root and received in a mortise within a hub. A flexible joint is provided between the tenon and the mortise.

Description

Technical Field

[0001] This invention relates to an annular propeller comprising multiple blades, each blade being at least partially made of a fiber-reinforced polymer and having an end and a root. A tenon is provided at the root and is received in a mortise in a hub. A flexible joint is provided between the tenon and the mortise. Background Technology

[0002] Propellers used to propel ships come in various sizes and types, such as open propellers, in which the propeller is arranged and rotated by a shaft connected to the machine, and electromagnetic propulsion, in which blades are arranged in a rotor configuration including magnets, and a stator with electric coils rotates the rotor. The propeller blades are connected to a hub at their root. In some cases, the tips of the blades are also connected to external tubular elements, such as those located in the propeller (e.g., azimuth thrusters).

[0003] Propeller blades generate thrust that propels a ship due to their hydrodynamic shaping. However, during thrust generation, the blades are subjected to even greater hydrodynamic forces, resulting in high stress throughout the blade. Furthermore, high stress is also generated at the root and tip sections (if connected to tubular elements) due to bending moments generated, for example, by hydrodynamic forces at the root and tip.

[0004] Traditionally, propeller blades are made of metal or metal alloys because the material properties of metals or metal alloys (such as toughness and ductility) are attractive in an attempt to avoid, for example, the formation of cracks at the root and / or tip of the blade joint.

[0005] While propeller blades made of metal or metal alloys perform well over long periods of use, there are some drawbacks to their production. One significant drawback is the extremely high weight of blades made of metal or metal alloys. Due to the rotation of the blades, the moment of inertia (which is related to the weight) is quite large. While this is less significant for propellers operating at a constant rotational speed, the considerable moment of inertia negatively impacts propellers operating at different speeds because of the increased response time and the substantial power required to change the operating speed.

[0006] Therefore, it is advantageous to reduce the "rotational mass" of the propeller and, in particular, reduce the weight of the blades.

[0007] Producing blades from fiber-reinforced polymers may be feasible because such blades are relatively lighter than metal or metal alloy blades. Furthermore, the blades need to be attached to the hub to provide rotation, and the resulting thrust will be transmitted from the hub to the vessel. During this process, the blades attached to the hub will be exposed to tensile and compressive stresses of typical amplitude varying over time, especially at the point or area where the blades are attached to the hub or end-to-end tubular elements. Therefore, attempting to use blades made of fiber-reinforced polymers inevitably leads to technical challenges related to how the blades are attached to the hub.

[0008] Therefore, it may be advantageous to use blades made of fiber-reinforced polymers in propeller configurations.

[0009] Purpose of the invention

[0010] The object of the present invention is to provide a propeller in which the blades are made of fiber-reinforced polymer.

[0011] Another object of the present invention is to provide an alternative to the prior art.

[0012] In particular, the object of the present invention can be considered as providing a propeller having blades made of fiber-reinforced polymer, which solves or at least alleviates the problems mentioned above. Summary of the Invention

[0013] Therefore, in a first aspect of the invention, the above-mentioned object and several other objects are intended to be achieved by providing an annular propeller comprising:

[0014] • Wheel hub,

[0015] • Tubular elements, arranged coaxially with the hub, and

[0016] • Multiple blades, each having at least a portion (e.g., all) made of fiber-reinforced polymer and having an end and a root, are arranged between a hub and a tubular element, wherein the ends are connected to the tubular element.

[0017] For each of the leaves:

[0018] • A tenon is provided at the base, which is received in a mortise provided in the hub, and

[0019] • A flexible joint is provided between the tenon and the mortise, the tenon having a constant thickness and / or gradually tapering in the radial inward direction of the propeller, the mortise and tenon being shaped together to provide an initial gap between the lateral surfaces of the mortise and tenon.

[0020] A flexible adhesive material is provided to essentially fill the first gap.

[0021] A ring propeller is a type of propeller in which blades are connected to a hub at their root, and the tips of the blades are connected to a tubular element, commonly referred to as a ring, hence the name "ring propeller". One embodiment of a ring propeller is shown in... Figure 1 and Figures 2A-2D As shown in the image.

[0022] In a preferred embodiment, the annular propeller is an annular propeller for a vessel, such as a watercraft, small boat, ship, hovercraft, planing submarine, submersible vessel, or submarine. In such embodiments, the annular propeller can be configured and used to propel the vessel by rotating the annular propeller. A vessel generally refers to a means of transportation designed for traversing or crossing bodies of water.

[0023] "At least partially made of fiber-reinforced polymer" can mean that the blade can be made of fiber-reinforced polymer, preferably substantially entirely, or that a portion or segment of the blade can be made of fiber-reinforced polymer. The latter can be achieved, for example, through a shell structure, wherein the blade includes a shell that may or may not include a core material, such as foam, for example, polyurethane foam. In a preferred embodiment, the entire external shape of the blade is provided by the fiber-reinforced polymer. Thus, in such embodiments, the trailing edge, the leading edge, and the region connecting the leading and trailing edges are provided by the fiber-reinforced polymer.

[0024] "Flexible adhesive material" preferably refers to a polymer. The choice of which polymer to use for a given application may often depend on the geometry of the part and the expected loads and deformations during use. As part of the design process, the specific polymer to be used can be determined by using computer simulations and / or experiments. In some embodiments, the flexible adhesive material provides adhesive bonding. The polymer is preferably a solidifiable polymer, such as a curable polymer that is flexible after solidification (e.g., in a cured state). Attached Figure Description

[0025] The invention, and particularly its preferred embodiments, will now be disclosed in more detail with reference to the accompanying drawings. The drawings illustrate modes of implementation of the invention and should not be construed as limiting other possible embodiments falling within the scope of the appended claims.

[0026] Figure 1 This is a 3D view of the annular propeller according to the first embodiment;

[0027] Figure 2A yes Figure 1 A 3D view of the annular propeller shown. Figure 2A The diagram shows a plane GG, from which a network is formed. Figure 2B A cross-sectional view. Figure 2C and Figure 2Dyes Figure 2B A close-up view. Detailed Implementation

[0028] refer to Figure 1 The figure illustrates a first embodiment of a ring propeller according to the invention. The ring propeller 1 includes a hub 2. As shown, the hub 2 has an opening 24, and the opening 24 is shaped as a receiving shaft (not shown). This shaft can be a drive shaft for rotating the propeller, or, for example, a rotatable shaft that allows the propeller to rotate when the ring propeller is used in an electromagnetic thruster configuration.

[0029] The annular propeller 2 includes a tubular element 4 arranged coaxially with the hub 2 and a plurality of blades 5. The blades 5 are at least partially made of fiber-reinforced polymer and each has an end 6 and a root 7. The plurality of blades 5 are arranged between the hub 2 and the tubular element (4), wherein the end 6 is connected to the tubular element 4.

[0030] As in Figures 2A-2D As can be seen most clearly, each of the blades 5 has a tenon 9 located at the root 7, which is received in a mortise 8 located in the hub 2.

[0031] Due to hydrodynamic forces, the propeller is subjected to relatively high loads, and the root section of the blades, in particular, may experience bending moments. To accommodate such loads, a flexible joint is provided between the tenon 9 and the mortise 8. In a preferred embodiment, each of the tenons 9 has a constant thickness, while in other embodiments, each of the tenons 9 tapers gradually in the radially inward direction of the propeller 1. Figures 2A-2D In the illustrated embodiment, the tenon 9 has a constant thickness. The tenon 9 and the mortise 8 are mutually shaped and sized to receive the tenon 9, thereby providing a first gap δ1 between the mortise 8 and the side-facing surfaces 12 of the tenon 9, as shown. Figures 2A-2D As shown. The gap δ1 is substantially filled with flexible adhesive material 10 so as to substantially occupy the gap δ1. The flexibility of the adhesive material 10 allows some movement of the tenon 9 within the mortise 8, which has been found to have a positive effect on reducing stress in the root section during propeller use.

[0032] Although in some embodiments the lower end of the tenon 9 may abut the bottom surface of the mortise 8, a gap may be provided. This can be achieved by dimensioning the mortise 8 and the tenon 9 to provide a second gap δ2 between the downward-facing surfaces 13 of the mortise 8 and the tenon 9. A flexible adhesive material 10 is provided to substantially fill the second gap δ2, thereby substantially occupying the gap δ2.

[0033] The bonding material combined with the first gap δ1 and / or the second gap δ2 and / or the third gap δ3 (as described below) not only increases the flexibility of the joint, but also prevents direct contact between the surface of the tenon 9 and the surface of the mortise 8, which could otherwise lead to surface deterioration due to wear.

[0034] During propeller rotation, propeller blades may tend to bend in the radial and / or tangential directions, and such bending can create stress concentration in the root region of the blades. This stress concentration may increase if the root segment of blade 5 is adjacent to the edge of a hub formed of a hard material (such as stainless steel). This could potentially occur at the outer edge of the tenon 8. To mitigate this potential stress concentration, the tenon 8 and tenon 9 are dimensioned to provide a third gap δ3 between the lateral surfaces 12 of the tenon 8 and tenon 9. The third gap δ3 is located at the upper end 14 of the tenon and extends radially to the outer surface 15 of the hub 2. Preferably, the third gap δ3 has an increased width in the radial direction. This third gap δ3 can be substantially filled with adhesive material 10, thereby substantially occupying the third gap δ3.

[0035] During use, the forces acting on the propeller blades 5 are typically relatively high at the root, for example due to bending moments. Since the blades are made of fiber-reinforced polymer, it has been found advantageous that each of the blades 5 includes a transition root section 19 at the root 7, which can be considered as a thickening of the blade 5 at the root 7, to allow the blade 5 to better absorb the forces acting at the root 7. The transition root section 19 preferably extends a distance in the radial direction of the propeller from above the tongue 8 to a section of the blade 5 shaped to provide thrust during rotation.

[0036] Sudden changes in the geometry of a stressed object can cause localized stress concentrations. To mitigate such effects in embodiments including a transition root section, a transition region 20 is provided, located where the transition root section 19 extends into the section of the blade 5 shaped to provide thrust. The transition region preferably continues with curvature (preferably continuous curvature) to reduce stress concentrations in the transition region 20.

[0037] Typically, the blades are twisted, meaning the chord length changes direction along the blade's length. This usually means the chord line at the root of the blade is angled relative to the propeller's axial direction. In a preferred embodiment, this is achieved by aligning the tenon 8 and tenon 9 with the orientation of the chord line at the root of the blade 5.

[0038] In many preferred embodiments, the fiber-reinforced polymer is a carbon fiber-reinforced polymer, although other fibers, such as Kevlar, glass fiber, or even combinations thereof, are used in other embodiments. It should be further noted that the blade 5 may not be made largely or entirely of the fiber-reinforced polymer, as the blade may be a core structure, such as a hollow core.

[0039] Preferably, each end 6 is connected to the tubular element 4 by being received in a groove 22 disposed in the tubular element 4. As disclosed in combination with the tenon 8 and the tenon 9, a gap may also be provided in the groove connection (the combination of the groove 22 and the end 6), preferably together with the adhesive material.

[0040] The end portion 6 may include a connecting segment 23 at the outermost position of the blade 5. This connecting segment typically has a thickness t that is greater than the thickness measured internally of the blade 6 immediately adjacent to the connecting segment 23. b Larger width w c At least a portion of the connecting section 23 is preferably received in the groove 22 along with the adhesive material.

[0041] In a preferred embodiment, the adhesive material is a polymer.

[0042] In a preferred embodiment, the hub 2 may be made of a metallic material (such as stainless steel). The tubular element 4 may be made of a fiber-reinforced polymer composite material or a metallic material (such as stainless steel).

[0043] In a preferred embodiment, the present invention relates to a permanent magnet propeller having a propeller 1 according to a preferred embodiment of the invention. In such an embodiment, the propeller includes a shaft on which a hub 2 is rotatably arranged. A plurality of permanent magnets 4 are disposed on or on the lateral surface of a tubular element 3. The magnets are preferably encapsulated in a cover so that they are not exposed to water during use.

[0044] The permanent magnet propulsion unit also has a stator yoke (not shown) arranged outside the tubular element 3 and the magnet (including an optional cover). The stator yoke has a plurality of stator coils that can be magnetized by electric current. The plurality of permanent magnets 4 and the plurality of stator coils 16 are configured to interact such that when the plurality of stator coils are magnetized, the rotor yoke rotates the propeller 1.

[0045] In a preferred embodiment, the present invention relates to a marine propulsion system including a propeller according to a preferred embodiment. In such embodiments, the propeller is arranged on a shaft rotatable by a motor, such as an electric motor, a hydraulic motor, or an internal combustion engine (e.g., an Otto engine or a diesel engine).

[0046] Assembly of the annular propeller according to a preferred embodiment of the invention can be performed as follows. First, the tenon 9 of the propeller blade is inserted into the mortise 8 provided in the hub 2. The tubular element is preferably pre-cast and ready for application to the annular propeller. In some embodiments, the tubular element 4 has internal dimensions that allow it to slide on the end of the propeller blade to position the end of the blade at the inner surface of the tubular element, after which the end of the blade is bonded to the tubular element by a flexible adhesive material.

[0047] In other embodiments, the tip of the blade is introduced into relation to... Figures 2A-2D In the disclosed grooved tubular element, a portion of the connecting segment 23 is introduced into the groove 22. In such embodiments, the second gap δ2 is sized such that the tenon 9 can be radially displaced inward to a certain extent, thereby positioning the tubular element 4 in a position surrounding the end 6. This typically means that the dimension of the second gap δ2 is greater than or substantially equal to the depth of the groove 22.

[0048] With the blade 6 and tubular element 4 arranged in this manner, the blade 6 is moved radially outward, thereby introducing a portion of the connecting section 23 into the groove 22. This movement can advantageously be provided by one or more jacking screws (not shown) extending from the interior of the hub into the tenon 8. By tightening such jacking screws, the ends of the jacking screws abut against the underside of the tenon 9, thereby forcing the blade to introduce a portion of the connecting section 23 radially outward into the groove 22. Preferably, the groove 22 is pre-filled with adhesive material to preferably flexibly secure a portion of the connecting section 23 within the groove 22.

[0049] When a portion of the connecting section 23 is located within the groove 22, a flexible adhesive material is applied to the tenon 8 to fill gaps δ1 and δ2, and, if available, also to fill gap δ3. The adhesive material can advantageously fill the gaps under increased pressure to avoid voids forming within the adhesive material. The lifting screw can be safely removed once the adhesive material has solidified.

[0050] List of reference numerals used in the accompanying drawings:

[0051] 1. Circular propeller

[0052] 2 wheel hubs

[0053] 4. Tubular elements

[0054] 5 blades

[0055] 6. (The tip of the blade)

[0056] 7. (The base of the leaf)

[0057] 8. Mortise and tenon

[0058] 9. Tenon

[0059] 10. Adhesive materials

[0060] 12 Surfaces facing the side

[0061] 13. Lower surface

[0062] 15. Outer surface

[0063] 19 Transitional root section

[0064] 20 Transition Zone

[0065] 22. Trench

[0066] 23 Connecting Section

[0067] 24 Opening

[0068] δ1 First gap

[0069] δ2 Second gap

[0070] δ3 Third gap

Claims

1. A ring-shaped propeller (1), comprising: • Wheel hub (2) • A tubular element (4) arranged coaxially with the hub (2), and • A plurality of blades (5), each made at least partially of a fiber-reinforced polymer and having an end (6) and a root (7), the plurality of blades (5) being arranged between the hub (2) and the tubular element (4), wherein the end (6) is connected to the tubular element (4). For each leaf (5) • A tenon (9) is provided at the root (7), and the tenon (9) is received in a mortise (8) provided in the hub (2), and • A flexible joint is provided between the tenon (9) and the mortise (8), the tenon (9) having a constant thickness and / or tapering gradually in the radially inward direction of the propeller (1), the mortise (8) and the tenon (9) being shaped together to provide a first gap (δ1) between the mortise (8) and the side-facing surfaces (12) of the tenon (9), and a flexible adhesive material (10) is provided to substantially fill the first gap (δ1).

2. The annular propeller according to any one of the preceding claims, wherein, For each blade (2), the mortise (8) and the tenon (9) are sized to provide a second gap (δ2) between the downward-facing surfaces (13) of the mortise (8) and the tenon (9), wherein the flexible adhesive material (10) is configured to substantially fill the second gap (δ2).

3. The annular propeller according to any one of the preceding claims, wherein, For each blade (2), the mortise (8) and the tenon (9) are sized to provide a third gap (δ3) between the mortise (8) and the side-facing surfaces (12) of the tenon (9), the third gap (δ3) being located at the upper end (14) of the mortise and extending in the radial direction of the propeller to the outer surface (15) of the hub (2), wherein the third gap has an increased width in the radial direction.

4. The annular propeller according to any one of the preceding claims, wherein, Each of the blades (5) includes a transition root section (19) located at the root (7), the transition root section (19) extending a distance from above the tenon (8) in the radial direction of the propeller to the section of the blade (5) shaped to provide thrust during rotation.

5. The annular propeller according to claim 4, wherein, The transition region (20) continues with curvature, preferably with continuous curvature, to reduce stress concentration in the transition region (20), which is located in the section of the transition root section (19) extending into the blade (5) that is shaped to provide thrust.

6. The annular propeller according to any one of the preceding claims, wherein, For each of the blades (5), the tenon (8) and tenon (9) are aligned with the orientation of the chord located at the root of the blade (5).

7. The annular propeller according to any one of the preceding claims, wherein, The fiber-reinforced polymer is a carbon fiber-reinforced polymer.

8. The annular propeller according to any one of the preceding claims, wherein, For each blade, the end (6) is connected to the tubular element (4) by being received in a groove (22) provided in the tubular element (4) together with an adhesive material.

9. The annular propeller according to claim 8, wherein, For each blade, the end (6) includes a connecting segment (23) located at the outermost position of the blade, the connecting segment having a thickness (t) greater than that measured internally of the blade (6) immediately adjacent to the connecting segment (23). b Larger width (w) c ), and wherein at least a portion of the connecting segment (23) is received in the groove (22) together with the adhesive material.

10. The annular propeller according to any one of the preceding claims, wherein, The adhesive material is a polymer.

11. The annular propeller according to any one of the preceding claims, wherein, The hub is made of a metal material, such as stainless steel, and / or the tubular element is made of a fiber-reinforced polymer composite material or a metal material, such as stainless steel.

12. A permanent magnet propulsion device, comprising a propeller (1) according to any one of the preceding claims, the permanent magnet propulsion device further comprising: • The hub (2) is rotatably arranged on the shaft; • Multiple permanent magnets (4) are disposed on or at the lateral surface (5) of the tubular element (3); • Stator yoke (15), which is arranged outside the tubular element (3) and includes a plurality of stator coils (16) that can be magnetized by current. in • The plurality of permanent magnets (4) and the plurality of stator coils are configured such that when the plurality of stator coils are magnetized, the rotor yoke causes the propeller (1) to rotate.

13. A ship propulsion system comprising a propeller according to any one of claims 1-11, wherein, The propeller is mounted on a shaft that can be rotated by a motor, such as an electric motor, a hydraulic motor, an internal combustion engine, such as an Otto engine or a diesel engine.

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