Propeller vibration absorbing and damping device

Abstract

The application provides a propeller vibration absorption and damping device, and relates to the technical field of aviation damping. The propeller vibration absorption and damping device comprises a frequency modulation assembly and a vibration absorption assembly. The frequency modulation assembly is fixed at the connection position of the propeller and the driving device, and is used for flexibly connecting the propeller and the driving device to release the vibration freedom degree of the propeller. One end of the vibration absorption assembly is fixedly connected with the propeller and located in the surrounding of the frequency modulation assembly, so as to establish the vibration transmission path of the frequency modulation assembly to the vibration absorption assembly. The rest of the vibration absorption assembly extends out of the frequency modulation assembly, so as to offset the vibration of the propeller through vibration. The frequency modulation assembly can transmit the frequency-modulated vibration to the vibration absorption assembly inside, so that the vibration absorption assembly can better play a role. Through the synergistic effect of the frequency modulation assembly and the vibration absorption assembly, the vibration of the propeller can be efficiently inhibited, the vibration stress can be significantly reduced, and the damping effect can be improved.

Description

Technical Field

[0001] This invention relates to the field of aviation vibration reduction technology, and in particular to a propeller vibration absorption and reduction device. Background Technology

[0002] Electric vertical takeoff and landing (eVTOL) aircraft are a new type of urban air transportation. The propeller, as a key component generating lift and thrust in eVTOLs, directly affects the aircraft's flight efficiency, safety, and reliability. Under high-speed rotation, the propeller is prone to severe vibration due to aerodynamic load fluctuations, propeller structural design limitations, and assembly errors. This vibration not only shortens the propeller's fatigue life and causes loosening and cracking of structural components, but it is also transmitted through the fuselage to the cockpit, affecting the stability of the flight control system and passenger comfort, becoming a key technical bottleneck restricting the safety and reliability of the aircraft.

[0003] In existing technologies, electric vertical takeoff and landing (eVTOL) aircraft all incorporate vibration reduction and isolation measures between the motor and the aircraft. By altering the dynamic characteristics of the power system structure, frequency avoidance and suppression of resonance are achieved.

[0004] The applicant has discovered that the prior art has at least the following technical problems: In the prior art, the vibration reduction or isolation devices are mostly rigidly connected between the propeller and the motor, lacking elastic buffer devices. When the motor frequency is close to the natural frequency of the propeller, resonance is easily triggered, leading to stress concentration in the propeller and accelerating the initiation of fatigue cracks. Moreover, at the moment of motor start-up, the aforementioned vibration reduction devices will cause the propeller's inertial load to act directly on the motor shaft, resulting in a surge in motor shaft load, accelerating bearing wear, and also easily causing plastic deformation of the connecting parts. When the rigid connection encounters a sudden gust of wind, stall, or sudden change in attitude, the aerodynamic drag torque increases sharply and cannot be buffered, which may cause fatigue fracture of the propeller hub bolts, affecting the service life of the motor and fasteners.

[0005] Therefore, existing devices for propeller vibration reduction have poor vibration reduction and absorption effects. Summary of the Invention

[0006] The purpose of this invention is to provide a propeller vibration absorption and damping device to solve the technical problem that existing propeller vibration damping devices have poor vibration reduction and absorption effects. The various technical effects of the preferred solutions among the many technical solutions provided by this invention are detailed below.

[0007] To achieve the above objectives, the present invention provides the following technical solution: The propeller vibration absorption and damping device provided by the present invention includes a frequency modulation component and a vibration absorption component, wherein: The frequency modulation component is fixed at the connection position between the propeller and the drive device, and is used to flexibly connect the propeller and the drive device to release the vibration degree of freedom of the propeller. One end of the vibration-absorbing component is fixedly connected to the propeller and is located within the enclosure of the frequency tuning component, thereby establishing a vibration transmission path from the frequency tuning component to the vibration-absorbing component. The remainder of the vibration-absorbing component extends out of the frequency-tuning component, thereby counteracting the vibration of the propeller through vibration.

[0008] Preferably, the vibration-absorbing assembly includes a support arm, a leaf spring, and a counterweight, wherein: The support arm is located within the enclosure of the frequency modulation assembly and is fixedly connected to the propeller; The leaf spring is perpendicular to the support arm, the middle part of the leaf spring is fixed to the end of the support arm opposite to the propeller, and the counterweight is fixed to both ends of the leaf spring.

[0009] Preferably, the vibration-absorbing component needs to meet the following requirements: The mass ratio of the counterweight m2 to the propeller m1 is μ=m2 m1 takes values ​​in the range [0.1, 0.2]. The optimal tuning frequency ratio of the vibration absorption component needs to satisfy:

[0010] in, γ opt The optimal tuning frequency ratio of the vibration absorption component is μ, where μ is the mass m2 of the counterweight and the mass m1 of the propeller. The optimal frequency of the plate spring and the counterweight combination structure needs to satisfy:

[0011] in, f abs This is the optimal frequency for the combination of the plate spring and the counterweight. f n1 The first-order modal frequency of the propeller.

[0012] Preferably, the vibration-absorbing assembly further includes an arm cover, and the support arm includes a rod, a clamping plate, and a positioning post, wherein: The lower part of the rod is fixedly connected to the propeller, the clamping plate is fixed to the other end of the rod, and the positioning pin is fixed to the side of the clamping plate away from the rod. A positioning hole is provided at the center of the leaf spring, the positioning post passes through the positioning hole, the arm cover is fixedly connected to the positioning post, and the arm cover cooperates with the clamping plate to clamp and fix the leaf spring; a rubber pad is fixed between the leaf spring and the support arm and / or between the leaf spring and the clamping plate. The shape of the positioning post matches the shape of the positioning hole and can restrict the relative rotation of the support arm and the plate spring.

[0013] Preferably, the vibration-absorbing assembly further includes a bushing, wherein: The support arm has a limiting section and a connecting section, the diameter of the limiting section is larger than the diameter of the connecting section; the connecting section extends into the central hole of the propeller, the bushing is clamped and fixed between the hole wall of the central hole and the support arm, and a locking nut is threadedly connected to the connecting section and cooperates with the limiting section to clamp and fix the propeller. Preferably, a limiting structure is provided on the limiting segment, the limiting structure including a limiting notch, the limiting notch being located at one end of the limiting segment facing the connecting segment, the limiting notch being used to limit the relative torsion of the bushing and the support arm; Alternatively, the limiting structure may include a limiting boss, the shape of which matches the shape of the countersunk hole on the bushing, thereby limiting the relative torsion between the support arm and the bushing.

[0014] Preferably, the bushing includes an integrally formed sleeve body and a plate body, the sleeve body being clamped and fixed between the hole wall of the central hole and the support arm, and the plate body abutting against the side of the propeller opposite to the locking nut. Alternatively, the bushing may include an upper bushing and a lower bushing, the upper bushing being fixedly connected to the lower bushing and clamped between the wall of the central hole and the support arm, and at least a portion of the upper bushing and the lower bushing being abutted against the propeller by both sides of the propeller.

[0015] Preferably, the counterweight is cylindrical or streamlined; the counterweight includes an upper counterweight and a lower counterweight arranged symmetrically, and a locking member fixes the upper counterweight, the lower counterweight and the end of the plate spring.

[0016] Preferably, the frequency modulation assembly includes an upper pressure plate, a lower pressure plate, and a rubber block, wherein: The two rubber blocks abut against the upper and lower sides of the propeller respectively. The upper pressure plate and the lower pressure plate abut against the side of the corresponding rubber block away from the propeller. Fasteners pass through the upper pressure plate, the lower pressure plate, the rubber blocks and the propeller and fix the four together. The upper pressure plate, the lower pressure plate, and the rubber block are all annular structures, and the annular structures surround the connection end between the vibration absorption assembly and the propeller.

[0017] Preferably, a central hole and a side hole are provided at the connection position between the propeller and the drive device, with the side hole surrounding the central hole; the central hole is used to fix the bottom end of the vibration-absorbing assembly. The frequency modulation assembly further includes a limiting sleeve located within the side hole, with at least a portion of the rubber block extending into the side hole. The limiting sleeve passes through the rubber block, the upper pressure plate, and the lower pressure plate, and allows the fastener to pass through.

[0018] The propeller vibration absorption and damping device provided by this invention has the following advantages compared with the prior art: The frequency modulation component flexibly connects the propeller and the drive device, solving the technical problem that vibration energy cannot be effectively transferred to the vibration absorber due to excessively rigid connections. The frequency modulation component can release the propeller's vibration freedom. Since the fixed end of the vibration absorber is located within the enclosure of the frequency modulation component, the frequency modulation component can transmit the frequency-modulated vibration to the vibration absorber inside, allowing the vibration absorber to function better. Through the synergistic effect of the frequency modulation component and the vibration absorber, propeller vibration can be effectively suppressed, significantly reducing vibration stress. Effectively reducing propeller vibration can extend its fatigue life, reduce safety risks caused by vibration, reduce vibration interference to the flight control system, improve flight stability, and enhance ride comfort. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the propeller vibration absorption and damping device; Figure 2 This is a schematic cross-sectional view of the propeller vibration absorption and damping device in Embodiment 1; Figure 3 yes Figure 2 A magnified view of a section at point A in the middle; Figure 4 This is a schematic diagram of the structure of the support arm and the leaf spring. Figure 5 This is a schematic diagram of the first type of outrigger structure; Figure 6 This is a schematic diagram of the upper bushing in the first type of bushing structure; Figure 7 This is a schematic diagram of the lower bushing in the first type of bushing structure; Figure 8 This is a schematic diagram of the second type of outrigger structure; Figure 9 This is a cross-sectional view of the bushing and its fit with the propeller and support arm in the second type of propeller vibration absorption and damping device. Figure 10 This is a schematic diagram of the bushing with the second structure; Figure 11 This is a schematic diagram of a leaf spring. Figure 12 This is a schematic diagram of the overall structure of Embodiment 2 of the propeller vibration absorption and damping device; Figure 13 This is a schematic diagram of the propeller structure; Figure 14 It is a comparison graph of acceleration before and after the simulated vibration absorption; Figure 15 These are the actual data collected during the experiment before and after vibration absorption.

[0021] In the diagram: 1. Propeller; 11. Center hole; 12. Side hole; 2. Vibration damping assembly; 211. Arm cover; 212. Rubber pad; 213. Leaf spring; 2131. Positioning hole; 214. Counterweight; 215. Support arm; 216. Upper bushing; 217. Lower bushing; 22. Bushing; 221. Sleeve body; 222. Plate body; 23. Rod body; 231. Limiting section; 232. Connecting section; 24. Clamping plate; 25. Positioning pin; 26. Locking nut; 27. Limiting notch; 28. Limiting boss; 3. Frequency modulation assembly; 31. Upper pressure plate; 32. Lower pressure plate; 33. Rubber block; 34. Limiting sleeve; 35. Fastener. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] In the description of this invention, it should be understood that the terms "center," "length," "width," "height," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and "side," 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 invention and simplifying the description, and do not 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 invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] Electric vertical takeoff and landing (eVTOL) aircraft typically employ vibration reduction and isolation measures between the motor and the aircraft, with no precedent for installing vibration absorption and damping devices between the propeller and the motor. This invention provides a propeller vibration absorption and damping device that adopts a coaxial integrated layout of "center vibration absorption and peripheral frequency tuning." It aims to fundamentally solve the problem of poor vibration absorption by introducing flexible connections and precisely tuned power vibration absorption components.

[0025] The following is combined Figures 1-15 The technical solution provided by this invention will be described in more detail below.

[0026] Example 1: The present invention provides a propeller vibration damping device, which is installed in the central hub region of the propeller 1. This region is the core area where the propeller 1 and the drive device (such as a motor, not shown in the figure) achieve power connection. The damping device mainly includes two functional components: a frequency modulation component 3 located on the periphery and a vibration absorption component 2 located in the central region. The "periphery" refers to the area surrounding the vibration absorption component 2 and the fixed end of the propeller 1. Figure 1 As shown.

[0027] See Figures 1-13 As shown, the propeller vibration damping device includes a frequency tuning component 3 and a vibration absorption component 2. The frequency tuning component 3 is fixed at the connection position between the propeller 1 and the drive device, and is used to flexibly connect the propeller 1 and the drive device to release the vibration degree of freedom of the propeller 1. One end of the vibration absorption component 2 is fixedly connected to the propeller 1 and is located within the enclosure of the frequency tuning component 3, thereby establishing a vibration transmission path from the frequency tuning component 3 to the vibration absorption component 2. The remaining part of the vibration absorption component 2 extends out of the frequency tuning component 3, thereby canceling the vibration of the propeller 1 through vibration.

[0028] The function of the frequency modulation component 3 is to transform the traditional rigid connection between the propeller 1 and the drive device into a flexible connection, thereby releasing the vibration degree of freedom of the propeller 1 during the vibration process and creating the preconditions for the effective transmission of vibration energy.

[0029] The frequency modulation component 3 employs a ring-shaped, symmetrical stacked structure. As an optional implementation, see [link to implementation details]. Figures 1-3 , Figure 9 As shown, the frequency modulation assembly 3 in this embodiment includes an upper pressure plate 31, a lower pressure plate 32, and a rubber block 33. The two rubber blocks 33 abut against the upper and lower sides of the propeller 1, respectively. The upper pressure plate 31 and the lower pressure plate 32 abut against the side of the corresponding rubber block 33 away from the propeller 1. The fastener 35 passes through the upper pressure plate 31, the lower pressure plate 32, the rubber block 33, and the propeller 1 and fixes the four together. The upper pressure plate 31, the lower pressure plate 32, and the rubber block 33 are all annular structures, and the annular structure surrounds the connection end between the vibration absorption assembly 2 and the propeller 1.

[0030] The above structure enables the frequency modulation component 3 to be located outside the fixed end of the vibration absorption component 2 and the propeller 1. When the frequency modulation component 3 releases the degree of freedom of the propeller 1 and adjusts the vibration frequency, the vibration is transmitted to the vibration absorption component 2 through the transmission path from the periphery to the center, so that the vibration absorption component 2 can play a better role.

[0031] For ease of installation of frequency modulation component 3 and vibration absorption component 2, see [link / reference] Figure 13 As shown, a central hole 11 and a side hole 12 are provided at the connection position between the propeller 1 and the drive device, with the side hole 12 surrounding the central hole 11; see also Figure 3 and Figure 13 As shown, the central hole 11 is used to fix the bottom end of the vibration absorption assembly 2.

[0032] During assembly, several fasteners 35 (e.g., bolts) are sequentially passed through the upper pressure plate 31, the upper rubber block 33, the side hole 12 of the propeller 1, and the lower rubber block 33, and are then securely connected to the lower pressure plate 32. By adjusting the preload of the fasteners 35, appropriate pre-compression can be applied to the rubber block 33, thereby firmly fixing the entire frequency modulation assembly 3 to the propeller 1 and providing a preset connection stiffness. The rubber block 33 is preferably made of nitrile rubber or silicone rubber with high damping characteristics, and its cross-sectional shape can be designed as T-shaped or rectangular to ensure structural stability while providing axial and radial elasticity. This layered composite structure, consisting of the upper pressure plate 31, the lower pressure plate 32, the rubber block 33, and the hub of the propeller 1, allows the propeller 1 to use the rubber block 33 as an elastic fulcrum when subjected to vibration excitation, squeezing the rubber, releasing the degree of freedom of the propeller 1, and producing a slight oscillation or tilt relative to the output shaft of the drive device, thereby breaking the original rigid constraint and transmitting the vibration of the propeller 1 to the vibration absorption assembly 2.

[0033] See Figure 9As shown, the frequency modulation assembly 3 also includes a limiting sleeve 34, which is located inside the side hole 12. At least a portion of the rubber block 33 extends into the side hole 12. The limiting sleeve 34 passes through the upper and lower rubber blocks 33 and is fixed to the motor with the upper pressure plate 31 and the lower pressure plate 32 by fasteners 35. The above structure can better support the rubber block 33 and prevent damage to the rubber block 33.

[0034] The vibration absorption component 2 is the core component for absorbing vibration energy. In this embodiment, the vibration absorption component 2 is arranged within the central space surrounded by the ring-shaped frequency modulation component 3, forming a compact coaxial layout. The structure of the vibration absorption component 2 will be described below.

[0035] See Figures 1-12 As shown, the vibration damping component 2 of this embodiment includes a support arm 215, a leaf spring 213, and a counterweight 214. The support arm 215 is located within the enclosure of the frequency modulation component 3 and is fixedly connected to the propeller 1. The leaf spring 213 is perpendicular to the support arm 215. The middle part of the leaf spring 213 is fixed to one end of the support arm 215 away from the propeller 1. The counterweight 214 is fixed to both ends of the leaf spring 213.

[0036] The counterweight 214 is the mass element of the vibration-absorbing assembly 2, and its mass is one of the key parameters determining the system's natural frequency. In this embodiment, two counterweights 214 are provided, which are symmetrically clamped and fixed to the two free ends of the leaf spring 213 by bolts or the like. The purpose of the symmetrical arrangement is to maintain the dynamic balance of the entire vibration-absorbing assembly 2, so as to avoid introducing additional eccentric excitation during rotation. The material of the counterweight 214 can be a metal with a high density, such as steel, copper, or tungsten alloy, in order to achieve the required mass in a small volume.

[0037] As an alternative implementation, see [link to implementation details]. Figure 1 , Figure 8 As shown, in this embodiment, the counterweight 214 is a cylinder; the counterweight 214 includes an upper counterweight 214 and a lower counterweight 214 symmetrically arranged, and a locking member fixes the upper counterweight 214, the lower counterweight 214 and the end of the leaf spring 213. This structure facilitates the fixing of the counterweight 214 and the leaf spring 213, making installation convenient and reducing costs.

[0038] See Figure 3 and Figure 11 As shown, the leaf spring 213 is the elastic element of the vibration damping assembly 2, and is usually made of spring steel with a high elastic limit or composite materials (such as glass fiber or carbon fiber). Its shape is rectangular or a strip-shaped thin plate with widened ends. The central area of ​​the leaf spring 213 is firmly fixed to the upper end of the support arm 215.

[0039] To provide additional damping and protect the internal structure, see Figure 3 , Figure 4 and Figure 5 As shown, the vibration damping assembly 2 also includes an arm cover 211. A rubber pad 212 can be filled or vulcanized in the space between the arm cover 211 and the leaf spring 213. The rubber pad 212 can provide a certain viscoelastic damping to help dissipate energy when the leaf spring 213 vibrates, and can also seal and prevent dust and excessive displacement of the leaf spring 213.

[0040] To ensure the effectiveness and stability of vibration energy transmission and to prevent the plate spring 213 from twisting relative to the support arm 215 during vibration, this embodiment also features an anti-rotation structure.

[0041] See Figure 3 , Figure 4 Figure 5 and Figure 8 As shown, the support arm 215 includes a rod 23, a clamping plate 24, and a positioning post 25, wherein: the lower part of the rod 23 is fixedly connected to the propeller 1, the clamping plate 24 is fixed to the other end of the rod 23, and the positioning post 25 is fixed to the side of the clamping plate 24 opposite to the rod 23; see also Figure 11 and Figure 4 As shown, a positioning hole 2131 is provided at the center of the leaf spring 213, the positioning post 25 passes through the positioning hole 2131, the arm cover 211 is fixedly connected to the positioning post 25, and the arm cover 211 and the clamping plate 24 cooperate to clamp and fix the leaf spring 213; a rubber pad 212 is fixedly vulcanized between the leaf spring 213 and the support arm 215 and / or between the leaf spring 213 and the clamping plate 24; the shape of the positioning post 25 matches the shape of the positioning hole 2131 and can restrict the relative rotation of the support arm 215 and the leaf spring 213.

[0042] For details, see Figure 4 , Figure 5 and Figure 11 As shown, one or more anti-rotation planes are machined on the positioning post 25 at the upper end of the support arm 215, and a matching hole (e.g., replacing the round hole with a D-shaped hole or a polygonal hole with a platform) is machined on the positioning hole 2131 of the leaf spring 213. During assembly, the positioning post 25 is inserted into the positioning hole 2131 of the leaf spring 213. Through the geometric limiting effect of the anti-rotation plane and the matching hole, the relative rotation between the two can be effectively prevented, thereby ensuring that the vibration mode of the vibration absorption assembly 2 is the expected bending vibration, rather than the unexpected torsional vibration.

[0043] The connection structure between the support arm 215 and the propeller is described below: See Figure 3 , Figure 5 and Figure 6As shown, the vibration damping assembly 2 also includes a bushing, wherein: the support arm 215 has a limiting section 231 and a connecting section 232, the diameter of the limiting section 231 is larger than the diameter of the connecting section 232; the connecting section 232 extends into the central hole 11 of the propeller 1, the bushing is clamped and fixed between the hole wall of the central hole 11 and the support arm 215, and a locking nut 26 is threadedly connected to the connecting section 232, and cooperates with the limiting section 231 to clamp and fix the propeller 1.

[0044] See Figure 9 The connecting section 232 is used in conjunction with the locking nut 26 to lock the support arm 215 to the propeller 1.

[0045] See Figure 3 , Figure 6 and Figure 7 As shown, the support arm 215 passes through the central hole 11 of the propeller 1, but does not directly contact the propeller 1. Instead, it is positioned and connected to the central hole 11 of the propeller 1 through a bushing.

[0046] In one embodiment, see Figure 3 As shown, the bushing includes an upper bushing 216 and a lower bushing 217. The upper bushing 216 and the lower bushing 217 are fixedly connected and clamped and fixed between the hole wall of the central hole 11 and the support arm 215. At least a portion of the upper bushing 216 and the lower bushing 217 abut against the propeller 1 from both sides.

[0047] Specifically, the upper bushing 216 and the lower bushing 217 are pressed into the center hole 11 of the propeller 1, while the support arm 215 passes through the inner holes of these two bushings and is fixed by means of locking nuts 26, etc., to ensure that there is no relative movement between the support arm 215 and the bushings. This design allows the vibration of the propeller 1 to be transmitted to the support arm 215 through the bushings.

[0048] In another embodiment, see Figure 9 and Figure 10 As shown, the bushing 22 includes an integrally formed sleeve body 221 and a plate body 222. The sleeve body 221 is clamped and fixed between the hole wall of the central hole 11 and the support arm 215, and the plate body 222 abuts against the side of the propeller 1 away from the locking nut 26.

[0049] The integrated structure of bushing 22 combines the original two separate parts into one, which not only reduces the total number of parts and simplifies supply chain management and assembly processes, but also reduces the risk of assembly errors.

[0050] To prevent torsion between the bushing and the support arm 215, which would reduce product lifespan and affect vibration reduction, a limiting structure is provided on the limiting section 231 of the support arm 215 in this embodiment.

[0051] In the first embodiment, see Figure 5As shown, the limiting structure includes a limiting notch 27, which is located at one end of the limiting segment 231 facing the connecting segment 232. The limiting notch 27 is used to limit the relative torsion of the bushing and the support arm 215.

[0052] In the second implementation, see Figures 8-10 As shown, the limiting structure includes a limiting boss 28, the shape of which matches the shape of the countersunk hole on the bushing, thereby limiting the relative torsion between the support arm 215 and the bushing.

[0053] For details, see Figures 8-10 As shown, the radial cross section of the limiting boss 28 can be polygonal. The shape of the countersunk hole on the bushing matches the shape of the limiting boss 28, thereby preventing relative torsion between the support arm 215 and the bushing. Since the bushing is fixed on the propeller, relative torsion between the support arm 215 and the propeller 1 is also prevented.

[0054] In this embodiment, by setting the length of the plate spring 213 and the mass of the counterweight 214, the frequency of the vibration absorption component 2 is made close to that of the propeller 1, and the vibration of the propeller 1 is transmitted to the vibration absorption component 2.

[0055] The main function of vibration absorption component 2: As an independent mass-spring-damping system, vibration absorption component 2 absorbs the vibration energy of the main system and consumes it through its own vibration, thereby reducing the resonance amplitude of the main system. Its core application is to suppress vibrations at specific frequencies.

[0056] The vibration absorption and damping principle of this embodiment is: the natural vibration frequency f of the vibration absorption component 2 is... abs The natural frequency is determined by setting the stiffness of the plate spring 213 and the total mass m2 of the counterweight 214. This natural frequency is pre-tuned to the preset target vibration frequency f that the propeller 1 needs to suppress. n1 (Usually its first-order modal frequency) is matched. When the excitation frequency from the support arm 215 matches the natural frequency f of the vibration absorption component 2. absWhen the vibration is synchronized or very close to the resonance point, the vibration-absorbing component 2 resonates. At this time, the counterweight 214, constrained by the plate spring 213, vibrates with a large amplitude. According to the theory of vibration dynamics, near the resonance point, the response of the secondary system (vibration-absorbing component 2) is opposite to the excitation direction of the primary system (propeller 1). That is, the direction of the inertial force generated by the counterweight 214 is 180 degrees opposite to the vibration displacement direction of the propeller 1. This opposite inertial force acts back onto the support arm 215, which can just cancel out most of the original excitation force driving its vibration. From an energy perspective, the vibration energy that originally belonged to the propeller 1 is efficiently transferred to the vibration-absorbing component 2 through the established effective vibration transmission path (propeller 1 hub -> rubber block 33 -> bushing -> support arm 215), and is finally dissipated as heat energy through the internal damping of the plate spring 213 and the viscoelastic damping of the auxiliary rubber pad 212. As a result, the vibration amplitude of the propeller 1 itself is significantly suppressed, thereby achieving the purpose of vibration absorption and reduction.

[0057] To achieve the best vibration reduction effect, the design parameters in this embodiment follow specific optimization criteria.

[0058] Based on the aircraft's condition, the modes generated by the flapping of propeller 1 are known, such as the first mode at 40Hz, the second mode at 110Hz, and the third mode at 145Hz. If the counterweight 214 is selected to be 1kg, then the modes of the counterweight 214 and the leaf spring 213 need to be designed together to achieve a frequency close to 40Hz, preferably between 32-35Hz, by designing the length of the leaf spring 213 (to avoid the flapping frequency and the excitation frequency being too close).

[0059] Based on Newton's laws, the analysis is as follows: Mathematical model:

[0060] Where m1 is the mass of the main system (mast of propeller 1), m2 is the mass of counterweight 214, x1 is the displacement of propeller 1, and x2 is the displacement of counterweight 214. 1 represents the acceleration of propeller 1. 2 represents the acceleration of counterweight 214. 1 represents the speed of propeller 1. 2 represents the velocity of counterweight 214, C represents the damping coefficient of leaf spring 213, k1 represents the stiffness of propeller 1, and k2 represents the stiffness of leaf spring 213. F 0sin ωt The external harmonic excitation force is (F0 is the excitation amplitude, w is the excitation frequency). Frequency domain analysis can be used to deduce the relationship between the displacement response amplitude x1 of the main system and the frequency, and the parameters can be optimized to minimize x1.

[0061] The natural frequency of the vibration absorption component 2 needs to match the excitation frequency ω: ; Wherein, ωabs: the natural frequency of the vibration-absorbing component 2 (plate spring 213 and counterweight 214); K2: the stiffness of plate spring 213; m2: the weight of counterweight 214. The mass m2 of the counterweight 214 is typically 1 / 10 to 1 / 5 of the mass m1 of the main system (propeller 1), that is: =(0.1 0.2) μ is the mass ratio of the counterweight 214 mass m2 to the propeller 1 mass m1.

[0062] The larger μ is, the more vibration energy the vibration absorption component 2 can absorb, and the more significant the suppression of the resonance amplitude of the main system (propeller 1) is. When μ≥0.1, the resonance amplitude of the main system can be reduced by more than 50%; when μ=0.2, the vibration reduction effect is closer to the ideal state and can effectively counteract the periodic excitation vibration generated by the rotation of propeller 1.

[0063] Balancing installation and cost constraints: The installation space and load-bearing capacity of propeller 1 system are limited. If μ>0.2 (the vibration absorption mass exceeds 1 / 5 of propeller 1), it will increase the overall weight of the system, occupy too much space, and may also affect the dynamic balance and operating efficiency of propeller 1. If μ<0.1, the vibration reduction effect will be greatly reduced, making it difficult to meet engineering requirements.

[0064] Therefore, in this embodiment, the vibration absorption component 2 needs to satisfy the following: the mass ratio μ of the counterweight 214 mass m2 to the propeller 1 mass m1 is μ = m2. m1 takes values ​​in the range [0.1, 0.2]. Damped optimization: By introducing damping c, resonance peaks are suppressed and the effective bandwidth is broadened. The optimal damping ratio and tuning frequency ratio can be determined through H∞ optimization. ; The optimal tuning frequency ratio of vibration-absorbing component 2 needs to satisfy: γ opt =1 / (1+μ); in, ξ opt To achieve the optimal damping ratio, γ opt For the optimal tuning frequency ratio, μ is the mass ratio of the counterweight 214 mass m2 to the propeller 1 mass m1.

[0065] The optimal frequency of the plate spring 213 and counterweight 214 mating structure needs to satisfy:

[0066] Among them, f abs f is the optimal frequency for the mating structure of the leaf spring 213 and the counterweight 214. n1 The first-order modal frequency of the propeller is given.

[0067] Example: Propeller 1 has a first-order mode of 40Hz, a second-order mode of 110Hz, and a third-order mode of 145Hz. Propeller 1 weighs 5kg, and μ is taken as 0.15. According to mass ratio We obtain m² = 0.75 kg, according to... γ opt =1 / (1+μ) is approximately equal to 0.8696, according to γ opt =f abs / f n1 Calculated f abs =0.8696 40 = 34.8Hz.

[0068] See Figure 14 and Figure 15 As shown, Figure 14 It is a comparison graph of acceleration before and after the simulated vibration absorption; Figure 15 These are the actual data collected during the experiment before and after vibration absorption.

[0069] Depend on Figure 15 It can be seen that before vibration reduction, the amplitude values ​​in the X, Y, and Z directions were 380, 290, and 370, respectively, and after vibration absorption, the amplitude values ​​in the X, Y, and Z directions were 140, 70, and 110, respectively, with a vibration absorption effect of ≥65%.

[0070] Example 2: In aviation applications, any object protruding from the surface of a rotating component will generate significant drag in high-speed airflow. In the structure of Embodiment 1, the counterweight 214 adopts a conventional blunt body shape such as a cube or cylinder. When the propeller 1 rotates at high speed, the counterweight 214 will generate severe disturbances in the surrounding air, producing significant aerodynamic drag. This will directly increase the load on the drive motor and reduce the aircraft's range. At the same time, this severe airflow disturbance may also generate howling noise and may excite new, unintended aerodynamic vibrations, interfering with the vibration reduction effect.

[0071] To address this issue, this embodiment incorporates aerodynamically optimized design for the shape of the counterweight 214. Please refer to... Figure 12The figure shows a schematic diagram of the streamlined counterweight 214 used in this embodiment. The main difference from Embodiment 1 is that the counterweight 214 in this embodiment is no longer a simple geometric shape, but is designed as a streamlined counterweight 214 with a streamlined shape. This streamlined shape can be a cross-section similar to a teardrop shape, an airfoil shape, or a spindle shape.

[0072] During assembly, the streamlined counterweight 214 is fixed to both ends of the leaf spring 213. Its installation direction is specifically designed so that the long axis of its streamlined shape is roughly aligned with the tangential direction of the propeller 1's rotation, while its sharp tail faces the rear of the rotation.

[0073] When the vibration damping device with this streamlined counterweight 214 rotates at high speed with the propeller 1, its optimized shape can smoothly cut through the air, allowing the air to flow smoothly along its surface and merge steadily at the tail, thereby greatly reducing turbulence and pressure drag in the wake region. Compared with a blunt body shape of the same mass, the air resistance experienced by the streamlined counterweight 214 can be reduced by an order of magnitude.

[0074] The benefits of this optimization are multifaceted: First, it significantly reduces the rotational energy consumption of the vibration damping device itself, contributing to improved overall aircraft energy efficiency; second, due to reduced airflow disturbance, the aerodynamic noise generated by the rotation of the counterweight 214 is also greatly reduced; furthermore, an important technical effect is that it avoids unstable aerodynamic phenomena such as vortex shedding that may occur due to bluff body flow. By employing a streamlined counterweight 214, the working environment of the vibration absorption component 2 can be ensured to be free from unnecessary aerodynamic interference, allowing it to focus more on absorbing target frequency vibrations transmitted from the propeller 1 structure, thereby further improving the overall vibration damping performance and stability of the system.

[0075] The remaining structures, working principles, and frequency tuning methods of this embodiment are the same as those of the previous embodiment. It demonstrates how, based on achieving the core vibration reduction function, detailed optimization can further improve the overall performance of the product in practical applications, reflecting the advanced nature and completeness of the proposed solution in engineering practice.

[0076] The specific features, structures, or characteristics described in this specification may be combined in any suitable manner in one or more embodiments or examples.

[0077] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0078] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A propeller vibration absorption and damping device, characterized in that, Includes frequency modulation components and vibration absorption components, wherein: The frequency modulation component is fixed at the connection position between the propeller and the drive device, and is used to flexibly connect the propeller and the drive device to release the vibration degree of freedom of the propeller. One end of the vibration-absorbing component is fixedly connected to the propeller and is located within the enclosure of the frequency tuning component, thereby establishing a vibration transmission path from the frequency tuning component to the vibration-absorbing component. The remainder of the vibration-absorbing component extends out of the frequency-tuning component, thereby counteracting the vibration of the propeller through vibration.

2. The propeller vibration absorption and damping device according to claim 1, characterized in that, The vibration-absorbing assembly includes a support arm, a leaf spring, and a counterweight, wherein: The support arm is located within the enclosure of the frequency modulation assembly and is fixedly connected to the propeller; The leaf spring is perpendicular to the support arm, the middle part of the leaf spring is fixed to the end of the support arm opposite to the propeller, and the counterweight is fixed to both ends of the leaf spring.

3. The propeller vibration absorption and damping device according to claim 2, characterized in that, The vibration absorption component needs to meet the following requirements: The mass ratio μ = m2 / m1 of the counterweight and the propeller is [0.1, 0.2]. The optimal tuning frequency ratio of the vibration absorption component needs to satisfy: in, γ opt The optimal tuning frequency ratio of the vibration absorption component is μ, where μ is the mass m2 of the counterweight and the mass m1 of the propeller. The optimal frequency of the plate spring and the counterweight combination structure needs to satisfy: in, f abs This is the optimal frequency for the combination of the plate spring and the counterweight. f n1 The first-order modal frequency of the propeller.

4. The propeller vibration absorption and damping device according to claim 2, characterized in that, The vibration-absorbing assembly further includes an arm cover, and the support arm includes a rod, a clamping plate, and a positioning post, wherein: The lower part of the rod is fixedly connected to the propeller, the clamping plate is fixed to the other end of the rod, and the positioning pin is fixed to the side of the clamping plate away from the rod. A positioning hole is provided at the center of the leaf spring, the positioning post passes through the positioning hole, the arm cover is fixedly connected to the positioning post, and the arm cover cooperates with the clamping plate to clamp and fix the leaf spring; a rubber pad is fixed between the leaf spring and the support arm and / or between the leaf spring and the clamping plate. The shape of the positioning post matches the shape of the positioning hole and can restrict the relative rotation of the support arm and the plate spring.

5. The propeller vibration absorption and damping device according to claim 2, characterized in that, The vibration-absorbing assembly also includes a bushing, wherein: The support arm has a limiting section and a connecting section, the diameter of the limiting section being larger than the diameter of the connecting section; the connecting section extends into the central hole of the propeller, the bushing is clamped and fixed between the hole wall of the central hole and the support arm, and a locking nut is threadedly connected to the connecting section, cooperating with the limiting section to clamp and fix the propeller.

6. The propeller vibration absorption and damping device according to claim 5, characterized in that, The limiting segment is provided with a limiting structure, the limiting structure including a limiting notch, the limiting notch being located at one end of the limiting segment facing the connecting segment, the limiting notch being used to limit the relative torsion of the bushing and the support arm; Alternatively, the limiting structure may include a limiting boss, the shape of which matches the shape of the countersunk hole on the bushing, thereby limiting the relative torsion between the support arm and the bushing.

7. The propeller vibration absorption and damping device according to claim 5, characterized in that, The bushing includes an integrally formed sleeve body and a plate body. The sleeve body is clamped and fixed between the hole wall of the central hole and the support arm, and the plate body abuts against the side of the propeller away from the locking nut. Alternatively, the bushing may include an upper bushing and a lower bushing, the upper bushing being fixedly connected to the lower bushing and clamped between the wall of the central hole and the support arm, and at least a portion of the upper bushing and the lower bushing being abutted against the propeller by both sides of the propeller.

8. The propeller vibration absorption and damping device according to claim 2, characterized in that, The counterweight is cylindrical or streamlined; the counterweight includes an upper counterweight and a lower counterweight arranged symmetrically, and a locking member fixes the upper counterweight, the lower counterweight and the end of the plate spring.

9. The propeller vibration absorption and damping device according to claim 1, characterized in that, The frequency modulation assembly includes an upper pressure plate, a lower pressure plate, and a rubber block, wherein: The two rubber blocks abut against the upper and lower sides of the propeller respectively. The upper pressure plate and the lower pressure plate abut against the side of the corresponding rubber block away from the propeller. Fasteners pass through the upper pressure plate, the lower pressure plate, the rubber blocks and the propeller and fix the four together. The upper pressure plate, the lower pressure plate, and the rubber block are all annular structures, and the annular structures surround the connection end between the vibration absorption assembly and the propeller.

10. The propeller vibration absorption and damping device according to claim 9, characterized in that, The propeller and the drive device are provided with a central hole and a side hole at the connection position, with the side hole surrounding the central hole; the central hole is used to fix the bottom end of the vibration absorption assembly. The frequency modulation assembly further includes a limiting sleeve located within the side hole, with at least a portion of the rubber block extending into the side hole. The limiting sleeve passes through the rubber block, the upper pressure plate, and the lower pressure plate, and allows the fastener to pass through.

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