A built-in vibration damping device for propeller model test

Abstract

The invention relates to a propeller hub built-in damping device for propeller model test, belonging to the technical field of propeller model test. It comprises an annular propeller hub and a semi-closed propeller hub which are axially butted to form a propeller hub shell; the semi-closed propeller hub is provided with a rubber damping pad, and the two are embedded and combined through circumferential concave-convex grooves to transfer torque; a conical cavity damper is arranged in the cavity between the rubber damping pad and the annular propeller hub, and relies on static friction force to transfer torque and axial thrust, and rubber rings are arranged at both ends of the cavity to limit; positioning rings are arranged at both ends of the rubber damping pad to constrain radial deformation, and an end face pressing ring is arranged at the small end of the propeller hub to lock. The device is integrated and compact in structure, and can block the vibration transmission between the blade and the shaft.

Description

Technical Field

[0001] This invention relates to the field of propeller model testing technology, and in particular to a propeller hub built-in vibration damping device for propeller model testing. Background Technology

[0002] With the rapid development of technology in the field of shipbuilding and marine engineering, propeller model testing, as a core research method for predicting the propulsion performance of actual ships and obtaining basic data on flow-induced vibration, requires increasingly higher testing accuracy and data reliability. During propeller model testing, the alternating excitation force generated by the non-uniform flow on the propeller is transmitted to the drive shaft and test end through the hub structure, causing multi-dimensional vibration interference, which directly affects the measurement accuracy of core hydrodynamic parameters such as thrust and torque. Therefore, the industry usually sets up corresponding vibration reduction structures to weaken the vibration transmission path.

[0003] In related technologies, vibration control for propellers and drive shafts is mainly divided into two categories: active control and passive vibration reduction. Under the active control approach, for example, patent document No. 201911307938.7 proposes an active vibration control design method for propellers and drive shafts, achieving active vibration suppression through a matching vibration control algorithm. Under the passive vibration reduction approach, for example, patent document No. 201710573964.9 proposes a propeller excitation force friction reduction device, which uses a structure where a rubber pad and a cover plate are installed on the end face of the propeller hub to reduce axial excitation force. Furthermore, patent document No. 202323375133.0 discloses a propeller hub assembly that connects individual blades to the hub through multiple flanges, relying on limiting and anti-loosening designs to ensure reliable installation, thereby reducing vibration.

[0004] However, the aforementioned vibration control methods and related devices still have many limitations and cannot meet the vibration damping requirements of the propeller hub in the propeller model test: First, the active vibration control design method requires additional hardware such as sensors and controllers, resulting in a complex overall structure and control logic. Furthermore, it does not involve specific physical vibration reduction and isolation structural solutions, making it difficult to adapt to usage scenarios where the propeller model is small and the internal installation space of the propeller hub is limited. Secondly, the end-face excitation force friction reduction device only takes vibration reduction measures on the two end faces of the propeller hub, which can only cover the reduction of axial excitation force. It has no vibration reduction effect on the radial excitation force generated during propeller rotation. At the same time, there is still a hard connection between the drive shaft and the blade, which inevitably produces bidirectional coupled vibration. Third, flange-connected hub assemblies are mainly suitable for air propellers assembled from single blades, and the hub and blades are still rigidly connected. They do not have the vibration reduction effect of reducing the transmission of blade vibration to the drive shaft, and cannot reduce the interference of vibration on the accuracy of test from the root. Summary of the Invention

[0005] To address the shortcomings of the existing production technologies, the applicant provides a built-in vibration damping device for propeller model testing. Through integrated design, a vibration damping structure is arranged inside the propeller hub, enabling a relatively flexible connection between the propeller blades and the shaft. While ensuring the transmission of thrust and torque, this significantly reduces the bidirectional transmission and coupling vibration between the shaft and the blades, thereby reducing the vibration excitation of the propulsion system.

[0006] The technical solution adopted in this invention is as follows: The present invention provides a built-in vibration damping device for propeller model testing. The device includes an annular propeller hub and a semi-enclosed propeller hub that are axially connected. The annular propeller hub and the semi-enclosed propeller hub together constitute a propeller hub shell. The propeller hub shell has a large end and a small end that are axially opposite each other. The outer periphery of the annular propeller hub is used to fix and install the propeller blades. A rubber damping pad is coaxially sleeved on the outer side of the semi-enclosed propeller hub, and the rubber damping pad is disposed between the outer side wall of the semi-enclosed propeller hub and the inner side wall of the annular propeller hub. The outer sidewall of the semi-enclosed propeller hub is provided with an outward protrusion groove along the circumference, and the inner sidewall of the rubber damping pad is provided with an inner groove along the circumference. The outward protrusion groove and the inner groove are interlocked and used to transmit rotational torque. The outer wall of the rubber damping pad and the inner wall of the annular propeller hub form an annular cavity. A conical cavity damper is installed in the annular cavity. The inner wall of the conical cavity damper is in contact with the outer wall of the rubber damping pad, and the outer wall of the conical cavity damper is in contact with the inner wall of the annular propeller hub. The rotational torque and axial thrust are transmitted by the static friction of the contact surfaces. A large-end rubber ring for the propeller hub is provided on the side near the large end of the annular cavity, and a small-end rubber ring for the propeller hub is provided on the side near the small end. The large-end rubber ring and the small-end rubber ring for the propeller hub respectively abut against the two ends of the axial direction of the conical cavity vibration damper to limit the axial movement of the conical cavity vibration damper. A large-end positioning ring for the propeller hub is provided between the large end side of the rubber damping pad and the semi-enclosed propeller hub. An end face pressure ring is provided at the small end of the propeller hub housing. A small-end positioning ring for the propeller hub is provided between the end face pressure ring and the small end side of the rubber damping pad. The large end positioning ring of the propeller hub and the semi-enclosed propeller hub, as well as the small end positioning ring of the propeller hub and the end face pressure ring, are all connected and fixed by fixing screws. Its beneficial effects are as follows: Through the two-stage composite vibration damping structure composed of rubber damping pads and conical cavity vibration dampers, a complete flexible force transmission path is constructed between the drive shaft and the blades. While ensuring the reliable transmission of rotational torque and axial thrust, it simultaneously achieves multi-dimensional vibration isolation in the axial and radial directions, effectively weakening the transmission of unsteady flow-induced vibration of the blades to the drive shaft, while suppressing the reverse transmission of vibration from the drive shaft to the blade side, eliminating bidirectional coupled vibration, and reducing the interference of vibration on the accuracy of hydrodynamic parameter testing such as thrust and torque. The entire vibration damping structure is built into the blade hub housing, with a high degree of structural integration. No additional external components such as sensors and controllers are required, making it perfectly suited for application scenarios where the propeller model is small and the internal space of the blade hub is limited.

[0007] As a further improvement, the inner ring wall of the semi-enclosed propeller hub is provided with a keyway for key connection with the drive shaft to input torque; the small end face of the semi-enclosed propeller hub is provided with a threaded connection hole for connection and fixation with the end face pressure ring by fasteners. Its beneficial effects are as follows: the torque input form of key connection provides smooth transmission and high alignment accuracy, and it is compatible with the assembly interface of standard drive shafts in model tests, making it highly versatile; the end face threaded connection structure can not only achieve reliable locking of the end face pressure ring, but also apply axial preload to the internal damping components by adjusting the locking force, ensuring the contact fit of each damping component, improving the stability of force transmission and vibration damping, and at the same time facilitating the disassembly and assembly of the device and the replacement and maintenance of internal components.

[0008] As a further improvement, the inner wall of the annular rotor hub includes a cylindrical surface at the large end, a conical surface, and a cylindrical surface at the small end, from the large end to the small end. The outer conical surface of the conical cavity damper is fitted to the inner conical surface of the annular rotor hub. Its beneficial effects are as follows: the conical mating structure can evenly distribute the concentrated axial thrust transmitted by the blades to the entire conical contact area, reduce local contact stress, and improve the uniformity of force transmission and structural durability; at the same time, the conical structure has radial self-centering characteristics, which can automatically calibrate the coaxiality of the annular blade hub and the conical cavity vibration damper during the assembly process, reduce assembly deviation, and ensure the dynamic balance performance of the propeller during rotation.

[0009] As a further improvement, the conical cavity vibration damper is a closed cavity component made of fiber-reinforced rubber, and its cavity is filled with inert gas to reduce unsteady fluid-excited vibration through elastic deformation generated by pressure. Its beneficial effects are as follows: the fiber-reinforced rubber matrix has both high strength and high damping characteristics, which can withstand the static friction required for large torque transmission, while dissipating vibration energy through its own damping; the inert gas filled inside forms a compressible gas spring buffer structure, which can effectively absorb the high-frequency pulsating impact load generated by unsteady flow field, filter the alternating excitation component, and form a wide-frequency vibration reduction effect in combination with rubber damping pads, covering low-frequency to mid-high frequency vibration excitation.

[0010] As a further improvement, annular positioning ring mounting grooves are respectively opened on the large end face and the small end face of the rubber vibration damping pad. The positioning ring of the large end of the propeller hub is embedded in the positioning ring mounting groove on the large end side, and the positioning ring of the small end of the propeller hub is embedded in the positioning ring mounting groove on the small end side. Its beneficial effects are as follows: the grooved installation structure can achieve dual axial and radial limiting of the positioning ring, preventing the positioning ring from shifting during high-speed rotation and improving the reliability of the structure; at the same time, embedding the positioning ring into the end face of the rubber damping pad can make full use of the axial space inside the hub, further improve the structural integration, ensure the tight fit between the positioning ring and the rubber damping pad, and strengthen the radial constraint effect.

[0011] As a further improvement, a supplementary rubber pad is provided between the small end face of the rubber damping pad and the end face pressure ring. The supplementary rubber pad fills the assembly gap between the end face of the rubber damping pad and the end face pressure ring, and is used to transmit axial load and realize flexible connection at the end face. Its beneficial effects are as follows: supplementing the rubber pad can effectively fill the end face gap caused by the part's machining error and assembly tolerance, eliminate the axial movement of the internal damping component, and ensure the continuous and stable transmission of axial thrust; at the same time, an additional flexible buffer layer is formed between the rigid end face pressure ring and the rubber damping pad, further blocking the transmission path of axial vibration, and avoiding the impact wear caused by direct contact between the rigid end face pressure ring and the rubber damping pad, thus extending the service life of the component.

[0012] As a further improvement, both the large end positioning ring and the small end positioning ring of the propeller hub are annular rigid components. Multiple screw holes are distributed circumferentially on the ring body to constrain the radial eccentric deformation of the rubber damping pad and maintain the coaxiality of the propeller hub and the drive shaft. Its beneficial effects are as follows: symmetrically arranging rigid positioning rings at both ends of the rubber vibration damping pad can form a two-way radial support constraint on the rubber vibration damping pad, effectively suppressing the torsional deformation and radial eccentric offset generated by the rubber vibration damping pad during torque transmission, ensuring the rotational coaxiality of the entire damping device, avoiding additional vibration caused by eccentricity, and improving the dynamic balance performance of the propeller while ensuring the vibration damping effect.

[0013] As a further improvement, the end face pressure ring is provided with a radial centering step on the side facing the semi-enclosed propeller hub. The radial centering step is fitted with the inner ring hole of the semi-enclosed propeller hub to achieve coaxial positioning of the end face pressure ring and the semi-enclosed propeller hub. Its beneficial effects are as follows: through the clearance fit between the step and the inner ring hole, the end face pressure ring can be quickly aligned and assembled, reducing the assembly difficulty and improving the coaxial accuracy of the assembly; at the same time, the alignment step structure can withstand radial loads, enhance the end face pressure ring's resistance to eccentric loads, ensure that the end face pressure ring's clamping force on the internal components is evenly distributed along the circumference, and avoid uneven wear of the vibration damping components caused by uneven local clamping force.

[0014] As a further improvement, both the rubber damping pad and the conical cavity damper are detachable components, and the components with corresponding stiffness and damping parameters can be replaced according to the damping frequency band and load requirements of different test conditions. Its beneficial effects are as follows: the core vibration damping components adopt a modular and replaceable design, eliminating the need to replace the entire rotor hub. By simply replacing the rubber vibration damping pads and conical cavity vibration dampers with different stiffness and damping parameters, it can adapt to the vibration damping requirements under different rotor types, speeds, and load conditions, greatly improving the adaptability and reusability of the device, while reducing the use and maintenance costs of long-term testing and extending the service life of the overall device.

[0015] As a further improvement, the rubber damping pad, the conical cavity damper, the rubber ring at the large end of the rotor hub, the rubber ring at the small end of the rotor hub, the positioning ring at the large end of the rotor hub, and the positioning ring at the small end of the rotor hub are all integrated and built into the internal cavity of the rotor hub housing to form an integrated rotor hub damping unit. Its beneficial effects are as follows: the built-in integrated design allows the entire damping device to maintain a complete and smooth hub shape, without changing the flow channel morphology around the propeller, avoiding additional interference to the flow field near the blades, and ensuring the accuracy of hydrodynamic test results in model experiments; at the same time, the integrated unit structure facilitates overall disassembly and replacement, effectively improving the efficiency of test preparation and equipment maintenance. Attached Figure Description

[0016] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the present invention.

[0017] Figure 2 This is a cross-sectional view of the internal structure of the present invention.

[0018] Figure 3 This is a schematic diagram of the semi-enclosed propeller hub of the present invention.

[0019] Figure 4 for Figure 3 AA section view in the image.

[0020] Figure 5This is a schematic diagram of the annular propeller hub of the present invention.

[0021] Figure 6 for Figure 5 BB section view in the middle.

[0022] Figure 7 This is a schematic diagram of the structure of the conical cavity vibration damper of the present invention.

[0023] Figure 8 This is a schematic diagram of the structure of the rubber vibration damping pad of the present invention.

[0024] Figure 9 for Figure 8 CC section view in the image.

[0025] Figure 10 This is a schematic diagram showing the arrangement of the large-end positioning ring and the small-end positioning ring of the propeller hub according to the present invention.

[0026] Figure 11 This is a schematic diagram of the structure of the rubber rings at both ends of the propeller hub and the supplementary rubber pads of the present invention.

[0027] Figure 12 This is a schematic diagram of the end face pressure ring of the present invention.

[0028] The components include: 1. Semi-enclosed propeller hub; 2. Rubber damping pad; 3. Large end positioning ring of propeller hub; 4. Large end rubber ring of propeller hub; 5. Conical cavity vibration damper; 6. Annular propeller hub; 7. Small end rubber ring of propeller hub; 8. Supplementary rubber pad; 9. Small end positioning ring of propeller hub; 10. End face pressure ring; 11. Fixing screw. 101. External protrusion groove; 201. Inner groove. Detailed Implementation

[0029] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the description of the present invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0034] like Figure 1 , Figure 2 As shown in the figure, this embodiment discloses a propeller hub built-in vibration damping device for propeller model testing. The whole is a coaxial rotating integrated structure, mainly including a semi-enclosed propeller hub 1, a rubber damping pad 2, a large end positioning ring of the propeller hub 3, a large end rubber ring of the propeller hub 4, a conical cavity vibration damper 5, an annular propeller hub 6, a small end rubber ring of the propeller hub 7, a supplementary rubber pad 8, a small end positioning ring of the propeller hub 9, an end face pressure ring 10, and multiple sets of fixing screws 11. The semi-enclosed hub 1 and the annular hub 6 are coaxially connected to each other along the axial direction, forming a hub shell for accommodating all vibration damping components. The hub shell has a large end and a small end that are opposite each other in the axial direction. The outer peripheral wall of the annular hub 6 is used to fix and install multiple blades of the propeller. All vibration damping, positioning and connecting components are integrated and built into the internal cavity of the hub shell, without changing the streamlined profile of the hub and avoiding additional interference to the flow field around the propeller.

[0035] like Figure 3 , Figure 4 As shown, the semi-enclosed hub 1 is an integral metal rotating component located on the inner center of the device, serving as the base for torque input and load bearing; The inner ring wall of the semi-enclosed propeller hub 1 has an axially extending keyway for connecting with an external drive shaft via a flat key to input rotational torque. The large end face of the semi-enclosed propeller hub 1 extends outward to form an annular retaining edge, the outer end face of which is flush with the large end face of the propeller hub, for axially limiting the large end side of the internal rubber damping pad 2 and conical cavity damper 5. Multiple external protrusions 101 are evenly arranged circumferentially on the outer cylindrical wall of the semi-enclosed propeller hub 1, extending axially and protruding from the outer wall surface of the semi-enclosed propeller hub 1. Multiple threaded connection holes are evenly arranged circumferentially on the small end face of the semi-enclosed propeller hub 1 for connecting and fixing with the end face pressure ring 10 via fixing screws 11, achieving axial locking and preload adjustment of the internal components.

[0036] like Figure 8 , Figure 9 As shown, the rubber damping pad 2 is a ring-shaped flexible component made of damping rubber through a mold, and is coaxially sleeved on the outside of the semi-enclosed propeller hub 1 to form the first-stage damping unit. Multiple inner grooves 201 are uniformly arranged along the circumference on the inner cylindrical wall of the rubber damping pad 2. The number, cross-sectional size and axial length of the inner grooves 201 are all matched one-to-one with the outer protrusions 101 on the semi-enclosed propeller hub 1. In the assembled state, the outer protrusion 101 is embedded in the inner groove 201 to form a circumferential fit. The rotational torque between the semi-enclosed propeller hub 1 and the rubber damping pad 2 is transmitted through the meshing of the protrusion and groove. At the same time, the elastic deformation of the rubber itself blocks the transmission path of radial and circumferential vibrations. The large end face of the rubber damping pad 2 has an annular large end positioning ring mounting groove, and the small end face has an annular small end positioning ring mounting groove. The two mounting grooves are used to install the propeller hub large end positioning ring 3 and the propeller hub small end positioning ring 9, respectively. The outer wall of the rubber damping pad 2 has a conical structure, and its taper is consistent with the inner conical surface of the conical cavity vibration damper 5, ensuring that the two fit tightly after assembly to stably transmit the static friction force of the contact surface.

[0037] like Figure 5 , Figure 6As shown, the annular hub 6 is a ring-shaped component made of metal, fitted onto the outside of the conical cavity vibration damper 5, forming the outer main body of the hub shell. The outer peripheral wall of the annular hub 6 is used to fix and connect the blades of the propeller, transmitting torque and thrust to the blades; The inner wall of the annular rotor hub 6 consists of a cylindrical surface at the large end, a conical surface, and a cylindrical surface at the small end, which are connected in a continuous manner from the large end to the small end. All three surfaces are precision machined and the inner surface is sandblasted to improve the surface friction coefficient and ensure reliable friction transmission with the conical cavity damper 5. The cone angle of the inner cone surface of the annular hub 6 is consistent with the angle of the outer cone surface of the cone cavity damper 5. After assembly, the two fit together completely, which can evenly distribute the axial thrust of the blade to the entire cone surface contact area. At the same time, it has radial self-centering characteristics to ensure the coaxiality of the assembly.

[0038] like Figure 7 As shown, the conical cavity damper 5 is a closed cavity component in the shape of an annular cone sleeve, which is set in the annular cavity formed between the rubber damping pad 2 and the annular blade hub 6, forming the second-stage damping unit. The base of the conical cavity vibration damper 5 is made of fiber-reinforced rubber, forming a sealed air-filled cavity filled with inert gas. The inner conical surface of the conical cavity vibration damper 5 is tightly fitted with the outer conical surface of the rubber damping pad 2, and the outer conical surface is tightly fitted with the inner conical surface of the annular hub 6. After assembly, under the action of axial preload, a large static friction force is generated between the conical cavity vibration damper 5 and the inner and outer side components, which can stably transmit rotational torque and axial thrust. When subjected to unsteady alternating excitation, the internal compressible gas and the rubber base together undergo elastic deformation, dissipating vibration energy, filtering pulsating load components, and achieving a buffering and vibration reduction effect.

[0039] like Figure 11 As shown, the rubber ring 4 at the large end of the rotor hub and the rubber ring 7 at the small end of the rotor hub are both ring-shaped components made of rubber. They are respectively set at both ends of the conical cavity vibration damper 5 and fill the gap between the conical cavity vibration damper 5 and the inner end face of the rotor hub housing. Among them, the rubber ring 4 at the large end of the rotor hub is located on the side of the annular cavity near the large end, and abuts against the large end face of the conical cavity damper 5 and the large end flange of the semi-enclosed rotor hub 1; the rubber ring 7 at the small end of the rotor hub is located on the side of the annular cavity near the small end, and abuts against the small end face of the conical cavity damper 5 and the supplementary rubber pad 8. Two rubber rings are used to limit the axial movement of the conical cavity vibration damper 5, and at the same time, to help buffer axial vibration and avoid rigid collisions between metal components. The supplementary rubber pad 8 is a ring-shaped pad made of rubber, which is set between the small end face of the rubber vibration damping pad 2 and the end face pressure ring 10. It is used to fill the end face gap caused by part machining errors and assembly tolerances, to ensure the continuous and stable transmission of axial load, and at the same time, to form a flexible buffer layer at the end face, further blocking the transmission of axial vibration to the end face pressure ring 10, and avoiding impact wear caused by direct contact between the rigid end face pressure ring 10 and the rubber vibration damping pad 2.

[0040] like Figure 10 As shown, the large end positioning ring 3 and the small end positioning ring 9 of the propeller hub are both annular rigid components, which are respectively embedded in the positioning ring mounting grooves at both ends of the rubber damping pad 2. Multiple screw holes are evenly distributed along the circumference of the two positioning rings. The positioning ring 3 at the large end of the propeller hub is connected and fixed to the large end side of the semi-enclosed propeller hub 1 by fixing screw 11. The positioning ring 9 at the small end of the propeller hub is connected and fixed to the end face pressure ring 10 by fixing screw 11. The two positioning rings form a bidirectional radial support constraint on the rubber damping pad 2, which can effectively suppress the torsional deformation and radial eccentricity offset generated by the rubber damping pad 2 during torque transmission, maintain the rotational coaxiality of the entire damping device, avoid additional vibration caused by eccentricity, and improve the dynamic balance performance of the propeller while ensuring the damping effect.

[0041] like Figure 12 As shown, the end face pressure ring 10 is an annular metal cap, installed on the small end side of the propeller hub housing. The end face pressure ring 10 has a radial centering step on the side facing the semi-enclosed propeller hub 1. The centering step is clearance-fitted with the inner annular hole of the semi-enclosed propeller hub 1 to achieve rapid coaxial positioning of the end face pressure ring 10 and the semi-enclosed propeller hub 1. Multiple screw holes are distributed circumferentially on the ring body of the end face pressure ring 10. The fixing screw 11 passes through the hole and is screwed into the threaded hole at the small end of the semi-enclosed propeller hub 1 to lock the end face pressure ring 10, thereby applying axial preload to all internal damping components and achieving axial fixation of the overall structure.

[0042] The assembly process of this device is as follows: First, the positioning ring 3 at the large end of the propeller hub is inserted into the positioning ring mounting groove at the large end of the rubber damping pad 2. The positioning ring 3 at the large end of the propeller hub is connected and fixed to the large end side of the semi-enclosed propeller hub 1 by fixing screw 11, thus completing the assembly of the rubber damping pad 2 and the semi-enclosed propeller hub 1. At this time, the outer protrusion 101 and the inner groove 201 are completely fitted. Then, the rubber ring 4 at the large end of the rotor hub is fitted onto the outer side of the large end of the rubber damping pad 2, and the conical cavity damper 5 is then fitted onto the small end side of the rubber damping pad 2, so that its inner conical surface is tightly fitted with the outer conical surface of the rubber damping pad 2. Next, the rubber ring 7 at the small end of the rotor hub is fitted onto the outside of the small end of the rubber damping pad 2, so that it abuts against the small end face of the conical cavity damper 5. Next, insert the annular hub 6 into the outer side of the conical cavity damper 5 from the large end side, so that the inner conical surface of the annular hub 6 is completely in contact with the outer conical surface of the conical cavity damper 5. Then, place the supplementary rubber pad 8 and the small end positioning ring 9 of the propeller hub on the small end face of the rubber damping pad 2 in sequence, fasten the end face pressure ring 10 and make the centering step embedded in the inner ring hole of the semi-closed propeller hub 1. Finally, insert all the fixing screws 11 and tighten them evenly, apply the set axial preload, and the assembly of the whole device is completed.

[0043] This device simultaneously performs torque transmission, thrust transmission, and vibration isolation functions. Its specific working principle is as follows: During the torque transmission process, the rotational torque output by the drive shaft is transmitted to the semi-enclosed propeller hub 1 through a key connection. The semi-enclosed propeller hub 1 drives the rubber damping pad 2 to rotate synchronously through the circumferentially fitted outer protrusion 101 and inner groove 201. Under the action of axial preload, a large static friction force is generated between the rubber damping pad 2 and the inner conical surface of the conical cavity damper 5, which in turn drives the conical cavity damper 5 to rotate synchronously. The conical cavity vibration damper 5 then drives the annular hub 6 to rotate through the static friction between its outer conical surface and the annular hub 6, ultimately driving the blades on the outer periphery of the annular hub 6 to rotate and do work. In the entire torque transmission path, the rubber damping pad 2 and the conical cavity damper 5 constitute a two-stage flexible transmission link, which stably transmits the rated torque while blocking the direct transmission path of rigid vibration.

[0044] During the thrust transmission process, the axial thrust generated by the blade rotation is transmitted from the blade to the annular hub 6, and the force is uniformly applied to the conical cavity damper 5 through the conical surface inside the annular hub 6. When the conical cavity vibration damper 5 is compressed, the internal gas is compressed, filtering out the alternating pulsating excitation component generated by the unsteady flow field, and transmitting the average axial thrust to the inner rubber damping pad 2. After the rubber damping pad 2 further buffers the attenuation, the thrust is transmitted to the semi-enclosed propeller hub 1, and finally transmitted to the drive shaft and test end through the semi-enclosed propeller hub 1. The thrust transmission process is buffered by two stages, which effectively attenuates the amplitude of pulsating loads and ensures the stability and accuracy of hydrodynamic parameter testing such as thrust and torque.

[0045] In terms of vibration reduction, this device achieves multi-dimensional, wide-frequency-range bidirectional vibration isolation through a composite vibration damping structure: Firstly, the rubber damping pad 2 and the conical cavity damper 5 together form a complete flexible connection path between the drive shaft and the blade. This can weaken the positive transmission of the flow-induced vibration on the blade side to the drive shaft and the test end, and also suppress the reverse transmission of the vibration at the drive shaft end to the blade side, thus eliminating bidirectional coupling vibration from the root. Secondly, the rubber damping pad 2 can simultaneously attenuate the radial, circumferential and axial vibration components. The conical cavity damper 5 further enhances the axial damping effect through air spring buffering. Combined with the end rubber ring and the end face buffer of the supplementary rubber pad, it can achieve all-directional vibration suppression and solve the defect that traditional end face damping can only cover the axial direction. Third, the high damping characteristics of the rubber matrix have a good dissipation effect on mid-to-high frequency vibrations, and the aeroelastic characteristics of the internal air-filled cavity have an excellent buffering effect on low-frequency pulsating loads. The combination of the two forms a wide-frequency vibration reduction capability, while improving the overall damping characteristics of the propeller hub and improving the self-sound performance of the propeller itself. Fourth, the rigid positioning rings at both ends constrain the eccentric deformation of the rubber damping pads, ensuring rotational coaxiality and avoiding additional vibrations caused by the deformation of the damping components. This maintains the dynamic balance accuracy of the thruster while ensuring the damping effect.

[0046] Furthermore, both the rubber damping pad 2 and the conical cavity damper 5 in this device are modular and replaceable components. When the test conditions, such as the propeller shape, speed, load, and target damping frequency band, change, the end face pressure ring 10 can be removed and the rubber damping pad 2 and the conical cavity damper 5 with corresponding stiffness, damping, and inflation parameters can be replaced to adapt to different test requirements without replacing the entire propeller hub device, which greatly improves the reusability and long-term economic efficiency of the device.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A propeller hub-embedded vibration damping device for propeller model testing, characterized in that, It includes an annular hub and a semi-enclosed hub that are joined together along the axial direction. The annular hub and the semi-enclosed hub together constitute the hub housing. The hub housing has a large end and a small end that are opposite each other in the axial direction. The outer periphery of the annular hub is used to fix and install the propeller blades. A rubber damping pad is coaxially sleeved on the outer side of the semi-enclosed propeller hub, and the rubber damping pad is disposed between the outer side wall of the semi-enclosed propeller hub and the inner side wall of the annular propeller hub. The outer sidewall of the semi-enclosed propeller hub is provided with an outward protrusion groove along the circumference, and the inner sidewall of the rubber damping pad is provided with an inner groove along the circumference. The outward protrusion groove and the inner groove are interlocked and used to transmit rotational torque. The outer wall of the rubber damping pad and the inner wall of the annular propeller hub form an annular cavity. A conical cavity damper is installed in the annular cavity. The inner wall of the conical cavity damper is in contact with the outer wall of the rubber damping pad, and the outer wall of the conical cavity damper is in contact with the inner wall of the annular propeller hub. The rotational torque and axial thrust are transmitted by the static friction of the contact surfaces. A large-end rubber ring for the propeller hub is provided on the side near the large end of the annular cavity, and a small-end rubber ring for the propeller hub is provided on the side near the small end. The large-end rubber ring and the small-end rubber ring for the propeller hub respectively abut against the two ends of the axial direction of the conical cavity vibration damper to limit the axial movement of the conical cavity vibration damper. A large-end positioning ring for the propeller hub is provided between the large end side of the rubber damping pad and the semi-enclosed propeller hub. An end face pressure ring is provided at the small end of the propeller hub housing. A small-end positioning ring for the propeller hub is provided between the end face pressure ring and the small end side of the rubber damping pad. The large end positioning ring of the propeller hub and the semi-enclosed propeller hub, as well as the small end positioning ring of the propeller hub and the end face pressure ring, are all fixed by fixing screws.

2. The propeller hub-embedded vibration damping device for propeller model testing according to claim 1, characterized in that, The inner ring wall of the semi-enclosed propeller hub is provided with a keyway for key connection with the drive shaft to input torque; the small end face of the semi-enclosed propeller hub is provided with a threaded connection hole for connection and fixation with the end face pressure ring by fasteners.

3. The propeller hub-embedded vibration damping device for propeller model testing according to claim 1, characterized in that, The inner wall of the annular rotor hub includes a cylindrical surface at the large end, a conical surface, and a cylindrical surface at the small end, from the large end to the small end. The outer conical surface of the conical cavity damper is fitted to the inner conical surface of the annular rotor hub.

4. The propeller hub-embedded vibration damping device for propeller model testing according to claim 1, characterized in that, The conical cavity vibration damper is a closed cavity component made of fiber-reinforced rubber, and its cavity is filled with inert gas to reduce unsteady fluid-excited vibrations through elastic deformation generated by pressure.

5. The propeller hub-embedded vibration damping device for propeller model testing according to claim 1, characterized in that, The rubber vibration damping pad has annular positioning ring mounting grooves on its large end face and small end face respectively. The positioning ring of the large end of the propeller hub is embedded in the positioning ring mounting groove on the large end side, and the positioning ring of the small end of the propeller hub is embedded in the positioning ring mounting groove on the small end side.

6. The propeller hub-embedded vibration damping device for propeller model testing according to claim 1, characterized in that, A supplementary rubber pad is also provided between the small end face of the rubber vibration damping pad and the end face pressure ring. The supplementary rubber pad fills the assembly gap between the end face of the rubber vibration damping pad and the end face pressure ring, and is used to transmit axial load and realize flexible connection at the end face.

7. The propeller hub-embedded vibration damping device for propeller model testing according to claim 1, characterized in that, Both the large-end positioning ring and the small-end positioning ring of the propeller hub are annular rigid components. Multiple screw holes are distributed circumferentially on the ring body to constrain the radial eccentric deformation of the rubber damping pad and maintain the coaxiality of the propeller hub and the drive shaft.

8. The propeller hub-embedded vibration damping device for propeller model testing according to claim 1, characterized in that, The end face pressure ring is provided with a radial centering step on the side facing the semi-enclosed propeller hub. The radial centering step is fitted with the inner ring hole of the semi-enclosed propeller hub to achieve coaxial positioning of the end face pressure ring and the semi-enclosed propeller hub.

9. The propeller hub-embedded vibration damping device for propeller model testing according to claim 1, characterized in that, Both the rubber damping pad and the conical cavity damper are detachable components. Depending on the damping frequency band and load requirements of different test conditions, the components with corresponding stiffness and damping parameters can be replaced.

10. The propeller hub-embedded vibration damping device for propeller model testing according to any one of claims 1 to 9, characterized in that, The rubber damping pad, the conical cavity damper, the rubber ring at the large end of the rotor hub, the rubber ring at the small end of the rotor hub, the positioning ring at the large end of the rotor hub, and the positioning ring at the small end of the rotor hub are all integrated and built into the internal cavity of the rotor hub housing, forming an integrated rotor hub damping unit.

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