A damper suitable for small unmanned aerial vehicle engines

Abstract

This invention discloses a vibration damper suitable for small unmanned aerial vehicle (UAV) engines, comprising a hollow mandrel and a concentric outer sleeve. The mandrel and outer sleeve are integrally formed by vulcanizing an elastomer. The elastomer includes an elastic body and vibration-damping through holes, which are disposed within the elastomer along the axis of the mandrel. By setting different stiffnesses in the radial (X-axis and Y-axis) and axial (Z-axis) directions, the vibration damper enables the engine system's modal frequencies to avoid the excitation frequencies of the UAV's main structure, preventing resonance, reducing vibration transmission between the engine and the small UAV's main structure, ensuring minimal displacement of the engine output shaft coupling center, and improving the flight stability, safety, and overall performance of the small UAV.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, and in particular to a vibration damper suitable for small UAV engines. Background Technology

[0002] Vibration reduction involves installing energy-dissipating devices at certain parts of a structure. These devices generate friction, bending, and elasto-plastic hysteresis deformation to dissipate or absorb the energy input to the structure through vibration, thereby reducing the vibration response of the main structure and achieving the purpose of vibration control.

[0003] Small drones rely on engines for power. Vibrations generated during engine operation are transmitted to the drone's fuselage, and vice versa. These vibrations can lead to increased displacement of the engine output shaft coupling. Excessive displacement of the coupling can cause a series of serious consequences: Firstly, it can cause instability in the connection between the engine output shaft and the coupling, generating additional vibrations that are transmitted throughout the drone's structure, affecting flight stability. Secondly, large displacement increases the wear rate of the coupling and adjacent components. Prolonged vibration and friction can cause surface material to gradually peel off, reducing component lifespan. Thirdly, large displacement can cause excessive stress on critical components such as bearings and gears. When this stress exceeds the components' load-bearing capacity, it can lead to premature bearing failure or gear breakage, thus affecting the overall performance of the drone. Finally, large displacement can also affect the drone's flight performance. Due to increased vibration and component wear, the drone's flight attitude may become unstable, and flight speed and control precision may decrease. These consequences directly affect the drone's flight stability, safety, and overall performance.

[0004] In summary, vibrations from small drone engines can cause a series of problems. Therefore, effective measures must be taken to reduce vibration transmission between the engine and the main structure of the small drone to ensure its safe, stable, and efficient operation.

[0005] A search revealed no patents or documents that are related to this invention.

[0006] In summary, designing a vibration damper suitable for small UAV engines that can prevent the engine system's modal frequencies from avoiding the excitation frequencies of the UAV's main structure, reduce vibration transmission between the engine and the small UAV's main structure, ensure small displacement of the engine output shaft coupling center, and improve the flight stability, safety, and overall performance of small UAVs are urgent problems to be solved. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the deficiencies in the existing technology by providing a vibration damper suitable for small unmanned aerial vehicle (UAV) engines. This damper can make the engine system modal frequency avoid the excitation frequency of the UAV main structure, prevent resonance, reduce vibration transmission between the engine and the main structure of the small UAV, ensure a small displacement of the engine output shaft coupling center, and improve the flight stability, safety and overall performance of the small UAV.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a vibration damper suitable for small unmanned aerial vehicle engines, comprising a hollow mandrel and an outer sleeve concentric with the mandrel, the mandrel and the outer sleeve being integrally formed by vulcanization of an elastomer; the elastomer comprising an elastic body and vibration damping through holes, the vibration damping through holes being disposed in the elastomer along the axial direction of the mandrel, the elastic body comprising vibration damping strips, the vibration damping strips being divided into two groups of vibration damping strips of different widths, a first vibration damping strip and a second vibration damping strip, wherein the thickness of the first vibration damping strip is w1, the thickness of the second vibration damping strip is w2, and the elastomer is disposed along the axial direction of the mandrel. Let the length of the elastic body be L; let the inner diameter of the part connected to the mandrel be D1, and the outer diameter of the part connected to the outer sleeve be D2; let the elastic modulus of the elastic body be E, and the shear modulus be G; let the direction perpendicular to the mandrel axis along the first damping belt be the X-axis, the direction perpendicular to the mandrel axis along the second damping belt be the Y-axis, and the direction along the mandrel be the Z-axis; let the stiffness along the X-axis be k1, the stiffness along the Y-axis be k2, and the stiffness along the Z-axis be k3, where w1, w2, L, D1, D2, E, G, k1, k2, and k3 satisfy:

[0009]

[0010] Furthermore, each end of the elastic body is provided with an inwardly recessed annular groove. Let the volume of the groove be V1, the outer radius of the part connecting the elastic body to the outer sleeve be R, and the change in this radius after compression be ΔR. Then, the following conditions are met:

[0011] Furthermore, let the arc length of the end of the damping belt connected to the inner circumference of the outer jacket be L1, and the arc length of the end of the damping belt connected to the outer circumference of the spindle be L2. Then L1 and L2 satisfy: L1 = L2.

[0012] Furthermore, the elastomer is a rubber material with a damping value ranging from 0.08 to 0.16.

[0013] Furthermore, the vibration damping through holes are four through holes with the same shape and size. The cross-section of the vibration damping through holes is fan-shaped. Let the central angle of the fan-shaped cross-section be θ, and let θ satisfy: θ=90°.

[0014] Furthermore, the vibration damping through hole adopts a rounded corner transition structure.

[0015] The beneficial effects of this invention are as follows: By installing this vibration damper on the engine of a small UAV, the modal frequency of the engine system can avoid the excitation frequency of the main structure of the UAV, preventing resonance, reducing the vibration transmission between the engine and the main structure of the small UAV, ensuring that the center displacement of the engine output shaft coupling is small, and improving the flight stability, safety and overall performance of the small UAV. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the vibration damper according to an embodiment of the present invention;

[0017] Figure 2 This is a top view of the vibration damper according to an embodiment of the present invention;

[0018] Figure 3 This is a cross-sectional view of the vibration damper in an embodiment of the present invention;

[0019] Figure 4 This is an axial cross-sectional view of the vibration damper in an embodiment of the present invention.

[0020] In the diagram: 1. Mandrel, 11. Mounting hole, 2. Outer sleeve, 3. Elastomer, 31. Elastic body, 311. Vibration damping belt one, 312. Vibration damping belt two, 313. Groove, 32. Vibration damping through hole. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the invention clearer, the following will be described in conjunction with the accompanying drawings of the embodiments of the invention. Figure 1-4 The technical solutions of the embodiments of the invention are clearly and completely described herein. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0022] It should be noted that all directional indications (such as up, down, forward, backward, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0023] Example:

[0024] This application discloses a vibration damper for small unmanned aerial vehicle (UAV) engines. After being press-fitted into a vibration damping bracket, it is integrally mounted outside the engine of the small UAV. During flight, it absorbs and buffers the vibration energy transmitted from the engine to the UAV, thereby reducing the impact on the UAV's airframe and ensuring flight stability. Figure 1 and Figure 2As shown, the vibration damper includes a hollow spindle 1 and a concentric outer sleeve 2. The spindle 1 and the outer sleeve 2 are formed into a single unit by vulcanization of an elastomer 3. The elastomer 3 includes an elastic body 31 and a damping through hole 32. The damping through hole 32 is disposed in the elastomer 3 along the axial direction of the spindle 1. The elastic body 31 includes a damping band, which is divided into two sets of damping bands with different widths: a first damping band 311 and a second damping band 312. Let the thickness of the first damping band 311 be w1, and the thickness of the second damping band 312 be w2. Let the axial length of the elastomer 3 be L. Let the elastomer 3 and the spindle 1 be... The inner diameter of the part connected to shaft 1 is D1, and the outer diameter of the part connected to outer sleeve 2 is D2. Let the elastic modulus of elastic body 3 be E, and the shear modulus be G. Let the direction perpendicular to the axis of mandrel 1 along damping belt 311 be the X-axis, the direction perpendicular to the axis of mandrel 1 along damping belt 312 be the Y-axis, and the direction along mandrel 1 be the Z-axis. Let the stiffness along the X-axis be k1, the stiffness along the Y-axis be k2, and the stiffness along the Z-axis be k3, where w1, w2, L, D1, D2, E, G, k1, k2, and k3 satisfy:

[0025]

[0026]

[0027] By designing the thickness w1 of damping belt 311, the thickness w2 of damping belt 312, and the length L of elastic body 3, the damper achieves a good damping effect, reducing the radial and axial vibrations caused by the engine to the main structure of the small UAV, thereby ensuring a small displacement of the engine output shaft coupling center. At the same time, the structure of elastic body 3 cooperating with spindle 1 and outer sleeve 3 meets the radial and axial stiffness requirements of the small UAV during flight, and also allows the engine system modal frequency to avoid the excitation frequency of the UAV main structure, preventing resonance, reducing vibration transmission between the engine and the main structure of the small UAV, ensuring a small displacement of the engine output shaft coupling center, and improving the flight stability, safety, and overall performance of the small UAV.

[0028] It should be noted that the spindle and outer sleeve in this embodiment are made of stainless steel.

[0029] like Figure 4 As shown, the elastic body 3 has inwardly recessed grooves 313 at both ends. Let the volume of the cross-sectional area of ​​the groove 313 be V1, the outer radius of the part where the elastic body 3 connects to the outer sleeve 1 be R, and the change in this radius after compression be ΔR. Then, the following conditions are met: During flight, the shock absorber is subjected to forces in different directions, and the elastomer 3 will be squeezed and deformed. The groove 313 provides space for the deformation of the elastomer 3, and will not interfere with or wear with other components, thus ensuring the life of the elastomer.

[0030] like Figure 2 As shown, in this embodiment, taking the second damping belt 312 as an example, let the arc length of the end of the second damping belt 312 connected to the inner circumferential surface of the outer sleeve 2 be L1, and the arc length of the end of the second damping belt 312 connected to the outer circumferential surface of the spindle 1 be L2. Then L1 and L2 satisfy: L1 = L2. This setting is to make the contact area S1 of the end of the second damping belt 312 connected to the inner circumferential surface of the outer sleeve 2 equal to the contact area S2 of the end of the damping belt connected to the outer circumferential surface of the spindle 1. Since L1 = L2, and S1 = L × L1, S2 = L × L2, S1 = S2 holds true. This setting is to ensure the lifespan of the second damping belt 312 when it is subjected to stress, since the stress and strain at both ends of the second damping belt 312 are the same. Similarly, the same applies to the first damping belt 311. This ensures the lifespan of the elastic body and further ensures the service life of the vibration damper.

[0031] In this embodiment, the elastic body is made of rubber material with a damping value ranging from 0.08 to 0.16. This rubber material can absorb and buffer the vibration energy transmitted by the engine, thereby giving the shock absorber a better vibration reduction effect.

[0032] like Figure 3 and Figure 4 As shown, the vibration damping through holes 32 are four through holes with the same shape and size. The cross-section of the vibration damping through holes 32 is fan-shaped. Let the central angle of this fan-shaped cross-section be θ, and let θ satisfy: θ=90°. This setting is to ensure that the thickness of the vibration damping band of the vibration damper is a constant value, which is beneficial to the setting of radial (X-axis and Y-axis) stiffness.

[0033] The vibration damping through hole 32 adopts a rounded corner transition structure; this allows the vibration damper to be better removed from the mold after vulcanization.

[0034] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the invention, which should be defined by the claims.

Claims

1. A vibration damper suitable for a small unmanned aerial vehicle (UAV) engine, comprising a hollow mandrel and a sleeve concentric with the mandrel, the mandrel and sleeve being integrally formed by vulcanization of an elastomer; the elastomer comprising an elastic body and a vibration damping through hole, the vibration damping through hole being disposed in the elastomer along the axial direction of the mandrel, characterized in that: The elastic body includes damping belts, which are divided into two groups of damping belts of different widths: damping belt one and damping belt two. Let the thickness of damping belt one be w1, and the thickness of damping belt two be w2. Let the axial length of the elastic body be L. Let the inner diameter of the part of the elastic body connected to the mandrel be D1, and the outer diameter of the part connected to the outer sleeve be D2. Let the elastic modulus of the elastic body be E, and the shear modulus be G. Let the direction perpendicular to the mandrel axis along damping belt one be the X-axis, the direction perpendicular to the mandrel axis along damping belt two be the Y-axis, and the direction along the mandrel be the Z-axis. Let the stiffness along the X-axis be k1, the stiffness along the Y-axis be k2, and the stiffness along the Z-axis be k3, where w1, w2, L, D1, D2, E, G, k1, k2, and k3 satisfy: ， ， 。 2. The vibration damper for small unmanned aerial vehicle engines according to claim 1, characterized in that: The elastic body has inwardly recessed annular grooves at both ends. Let the volume of the grooves be V1, the outer radius of the part connecting the elastic body to the outer sleeve be R, and the change in this radius after compression be ΔR. Then, the following conditions are met: .

3. The vibration damper for small unmanned aerial vehicle engines according to claim 1, characterized in that: Let L1 be the arc length of the end of the damping belt that connects to the inner circumference of the outer sleeve, and L2 be the arc length of the end of the damping belt that connects to the outer circumference of the spindle. L1 and L2 satisfy: L1=L2.

4. The vibration damper for small unmanned aerial vehicle engines according to claim 1, characterized in that: The elastomer is a rubber material with a damping value ranging from 0.08 to 0.

16.

5. The vibration damper for a small unmanned aerial vehicle engine according to claim 1, characterized in that: The vibration damping through holes are four through holes of the same shape and size. The cross-section of the vibration damping through holes is fan-shaped. Let the central angle of this fan-shaped cross-section be θ, and let θ satisfy: θ=90°.

6. The vibration damper for a small unmanned aerial vehicle engine according to claim 5, characterized in that: The vibration damping through hole adopts a rounded corner transition structure.

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