Variable-stiffness torsion-resistant shock absorber

Abstract

The utility model discloses a variable rigidity anti-torsion shock absorber which comprises an upper limiting piece, an upper rubber pad, a lower rubber pad and a lower limiting sleeve, and the lower limiting sleeve comprises a bottom and a fixedly connected cylinder part perpendicular to the center of the bottom. The lower rubber pad, the supporting lug of the object to be damped and the upper rubber pad are sequentially limited by the cylinder part from bottom to top, and the upper limiting piece is detachably connected to the top end of the cylinder part; first limiting grooves are formed in the upper rubber pad, first limiting bosses in one-to-one correspondence with the first limiting grooves are arranged on the lower surface of the upper limiting piece, and second limiting grooves are formed in the lower rubber pad. And second limiting bosses in one-to-one correspondence with the second limiting grooves are arranged on the upper surface of the bottom of the lower limiting sleeve. According to the variable-rigidity torsion-resistant shock absorber, the torsion rigidity of inertial measurement unit equipment in the bearing direction is effectively improved, and the navigation precision of the unmanned aerial vehicle model inertial measurement unit equipment of the shock absorber is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of passive vibration reduction, in particular to a variable-rigidity anti-torsion vibration reducer. Background Art

[0002] UAV models are constantly developing towards collaboration, informationization, and clustering, which also requires UAVs to meet the requirements of high maneuverability, high precision, long range, and high reliability. The navigation information of a single UAV needs to be as accurate as possible under the constraints of the mechanical environment. As the core component of the UAV strapdown inertial navigation system, the inertial group is responsible for measuring the acceleration of the carrier relative to space in a fast-moving carrier and obtaining various navigation information of the UAV through coordinate transformation. The harsh vibration and impact environment of the payload equipment puts forward strict requirements on the design of the inertial navigation system. From the perspective of vibration energy transfer, the shock absorber plays an isolating role between the inertial group equipment and the vibration source. In general, starting from the overall requirements of the system in engineering, in order to accurately measure the angular motion of the space carrier and overcome the limitations of the mechanical environment, the three-axis angular vibration resonance frequency must be higher than the cutoff frequency of the linear vibration. That is, for the inertial group, on the basis of meeting the three-way equal stiffness requirements of the carrier equipment, the linear resonance frequency should be low and the angular vibration frequency should be high. For traditional installation methods such as spatial symmetry of four points and spatial symmetry of eight points, the isotropy of the shock absorber causes the linear vibration frequency and the angular vibration to basically be in a fixed multiple relationship, and the angular vibration frequency cannot be increased while the linear vibration frequency is reduced or unchanged. Currently, rubber shock absorbers are widely used in UAV inertial group models, and the performance of shock absorbers needs to be improved to meet the high maneuverability requirements of UAVs. Utility Model Content

[0003] The utility model aims to provide a variable stiffness anti-torsion shock absorber to solve the problem that the performance of the existing shock absorber cannot meet the high maneuverability requirements of unmanned aerial vehicles.

[0004] The technical solution adopted to achieve the purpose of this utility model is:

[0005] A variable stiffness anti-torsion shock absorber, comprising an upper limit plate, an upper rubber pad, a lower rubber pad and a lower limit sleeve, wherein the lower limit sleeve comprises a bottom and a barrel portion fixedly connected to the center of the bottom, the lower rubber pad, the lug of the damped object and the upper rubber pad are sequentially limited by the barrel portion from bottom to top, and the upper limit plate is detachably connected to the top end of the barrel portion;

[0006] The upper rubber pad is provided with a plurality of first limiting grooves, the lower surface of the upper limiting plate is provided with a first limiting boss corresponding one-to-one and adapted to the first limiting grooves, the lower rubber pad is provided with a plurality of second limiting grooves, and the upper surface of the bottom of the lower limiting sleeve is provided with a second limiting boss corresponding one-to-one and adapted to the second limiting grooves.

[0007] In the above technical solution, the first limiting bosses are evenly distributed on the lower surface of the upper limiting plate along the axial direction of the shock absorber.

[0008] In the above technical solution, the second limiting bosses are evenly distributed on the upper surface of the bottom along the axial direction of the shock absorber.

[0009] In the above technical solution, the first limiting boss and the second limiting boss are arranged opposite to each other.

[0010] In the above technical solution, the first limiting boss and the second limiting boss have the same shape and the same number.

[0011] In the above technical solution, the first limiting boss is in a fan-shaped shape, and the first limiting boss is distributed along the outer edge of the lower surface of the upper limiting plate.

[0012] In the above technical solution, the number of the first limiting bosses is four, and the angle of the fan ring is 45°.

[0013] In the above technical solution, the height of the first limiting boss is smaller than the depth of the first groove, and the height of the second limiting boss is smaller than the depth of the second groove.

[0014] In the above technical solution, the upper rubber pad and the lower rubber pad are made of silicone rubber, and the upper limit plate and the lower limit sleeve are made of stainless steel or titanium alloy.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] 1. The shock absorber of the utility model utilizes structural improvements to change the large displacement characteristics of the traditional silicone rubber T-type shock absorber under large impact loads; secondly, the torsional stiffness of the inertial group equipment in the load-bearing direction is improved, effectively improving the navigation accuracy of the inertial group equipment of the UAV model of the shock absorber.

[0017] 2. The shock absorber of the utility model can perform three-way vibration reduction and buffering on the load equipment. The current angular vibration test technology and equipment in actual engineering are not yet mature. In theory, the linear frequency of the inertial group is required to be small and the angular frequency is large. Compared with the traditional shock absorber, the shock absorber of the utility model has the characteristics of small linear stiffness and large angular stiffness. It is suitable for vibration reduction and buffering of inertial group equipment in harsh mechanical environments, effectively suppressing the linear-angular coupling of the inertial group equipment, and improving the accuracy of the strapdown inertial group system. The shock absorber of the utility model has a variable stiffness characteristic. The increased stiffness under large loads and large impacts is conducive to reducing the impact displacement and preventing the equipment from failing due to collisions caused by large displacements.

[0018] 3. The structure of the upper limit plate and the lower limit sleeve made of metal in the utility model improves the ability of the shock absorber to resist large load impacts and limits the large displacement of the inertial group equipment to prevent collision and interference of the inertial group equipment during high-speed maneuvers of the UAV. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a schematic structural diagram of the variable stiffness anti-torsion vibration absorber of the utility model.

[0020] Figure 2 Shown is an exploded view of the variable stiffness anti-torsion shock absorber of the utility model.

[0021] Figure 3 Shown is the torsional displacement cloud diagram of the traditional T-type shock absorber.

[0022] Figure 4 Shown is a torsional displacement cloud diagram of the shock absorber of the utility model.

[0023] Figure 5 Shown is a load-displacement graph.

[0024] In the figure: 1-upper limit plate, 2-upper rubber pad, 3-lower rubber pad, 4-lower limit sleeve, 5-first limit boss, 6-first limit groove, 7-second limit groove, 8-second limit boss, 9-cylinder, 10-bottom. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] A variable stiffness anti-torsion vibration absorber, such as Figure 1-2 As shown, it includes an upper limit plate 1, an upper rubber pad 2, a lower rubber pad 3 and a lower limit sleeve 4, the lower limit sleeve 4 includes a bottom 10 and a barrel 9 fixedly connected to the center of the bottom 10, the lower rubber pad 3, the ear of the vibration-damped object and the upper rubber pad 2 are sequentially limited by the barrel 9 from bottom to top, and the upper limit plate 1 is detachably connected to the top of the barrel 9;

[0027] The upper rubber pad 2 is provided with a plurality of first limiting grooves 6, the lower surface of the upper limiting plate 1 is provided with a first limiting boss 5 which corresponds to and fits with the first limiting grooves 6 one by one, the lower rubber pad 3 is provided with a plurality of second limiting grooves 7, and the upper surface of the bottom 10 of the lower limiting sleeve 4 is provided with a second limiting boss 8 which corresponds to and fits with the second limiting grooves 7 one by one.

[0028] Specifically, the first limiting bosses 5 are evenly distributed on the lower surface of the upper limiting plate 1 along the axial direction of the shock absorber, and the second limiting bosses 8 are evenly distributed on the upper surface of the bottom 10 along the axial direction of the shock absorber. The first limiting bosses 5 and the second limiting bosses 8 are arranged opposite to each other, and the first limiting bosses 5 and the second limiting bosses 8 have the same shape and the same number.

[0029] Furthermore, the first limiting boss 5 is in a fan ring shape, and the first limiting boss 5 is distributed along the outer edge of the lower surface of the upper limiting plate 1. The number of the first limiting bosses 5 is four, and the included angle of the fan ring is 45°.

[0030] Furthermore, the height of the first limiting boss 5 is smaller than the depth of the first groove, and the height of the second limiting boss 8 is smaller than the depth of the second groove. When a small-scale vibration or impact occurs, the boss will not contact the groove part; when a large-scale vibration or impact occurs, the boss will contact the groove part, and the system stiffness will increase, which is beneficial to reducing the impact or vibration displacement.

[0031] The upper rubber pad 2 and the lower rubber pad 3 are made of silicone rubber, and the upper limit plate 1 and the lower limit sleeve 4 are made of stainless steel or titanium alloy.

[0032] Example 1

[0033] The inertial navigation device weighs 3kg, and the shock absorber is designed according to the four-point distribution in space. In this embodiment, the upper rubber pad 2 and the lower rubber pad 3 have the same structure, and the first limiting boss 5 is a fan ring with an outer diameter of 27.5mm, an inner diameter of 18mm, and an angle of 45°.

[0034] According to the finite element modal calculation results, the three-way frequencies are 45Hz, 45Hz, and 48Hz, and it is believed that the structure meets the three-way equal stiffness requirements.

[0035] The torsional stiffness of this structure is compared and analyzed with that of the traditional T-type shock absorber to determine the torsional stiffness characteristics of this structure. The specific calculation process is as follows: except for the different boss structures, the interface dimensions of the two shock absorbers are guaranteed to be the same, and the material parameters are kept consistent (the elastic modulus is 3MPa), the interface dimensions of the rubber pad are constrained, and a 1000Nmm torque is applied to the metal part of the shock absorber. The contact pairs all use rough contact in Workbench. The torsional stiffness of the traditional T-type shock absorber is 256Nmm / °, the torsional angle is 3.9°, and the torsional displacement cloud diagram is as follows: Figure 3 As shown; the torsional stiffness of the vibration damping pad of the present invention is 322Nmm / °, the torsion angle is 3.1°, and the torsional displacement cloud diagram is as follows Figure 4 shown.

[0036] The calculation shows that the structural torsional stiffness of the shock absorber of the utility model can be increased by 25% under the same interface size and rubber material. The difference between torsional stiffness and linear stiffness is large, which is reflected in the large difference between linear frequency and angular frequency in the equipment frequency. It satisfies the linear vibration reduction while suppressing angular vibration, and improves the accuracy of inertial navigation. It can effectively improve the line-angle coupling of the UAV inertial group equipment under large maneuvers, and thus improve the accuracy of inertial group solution.

[0037] The variable stiffness characteristic test of the shock absorber of the utility model is that during calculation, the metal part of the shock absorber (upper limit plate 1 and lower limit sleeve 4) is constrained, and a 4mm forced displacement is applied to the shock absorber. Compared with the traditional T-type shock absorber, the shock absorber of the utility model can improve the stiffness of the shock absorber through the structure when the shock absorber reaches a certain displacement, and has a variable stiffness characteristic in structure. The load-displacement curve is shown in Figure 5 It can be seen that in the first half, the linear stiffness of the shock absorber of the utility model is smaller than that of the traditional T-type shock absorber. Based on the torsional stiffness characteristic results, the linear stiffness and angular stiffness of the shock absorber of the utility model are greatly different at this time; and as the load increases, the shock absorber of the utility model will increase the stiffness by relying on the structural form to limit the position against large loads and large impacts.

[0038] For ease of explanation, spatial relative terms such as "upper", "lower", "left", "right" and the like are used in the embodiments to illustrate the relationship of one element or feature shown in the figure relative to another element or feature. It should be understood that, in addition to the orientation shown in the figure, the spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the element described as being "under" other elements or features will be positioned "on" other elements or features. Therefore, the exemplary term "under" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here can be interpreted accordingly.

[0039] Furthermore, relational terms such as “first” and “second” and the like are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any such actual relationship or order between these components.

[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A variable stiffness anti-torsion shock absorber, characterized in that: It includes an upper limit plate, an upper rubber pad, a lower rubber pad and a lower limit sleeve, wherein the lower limit sleeve includes a bottom and a barrel portion fixedly connected to the center of the bottom, the lower rubber pad, the ear of the vibration-damped object and the upper rubber pad are sequentially limited by the barrel portion from bottom to top, and the upper limit plate is detachably connected to the top end of the barrel portion; The upper rubber pad is provided with a plurality of first limiting grooves, the lower surface of the upper limiting plate is provided with a first limiting boss corresponding one-to-one and adapted to the first limiting grooves, the lower rubber pad is provided with a plurality of second limiting grooves, and the upper surface of the bottom of the lower limiting sleeve is provided with a second limiting boss corresponding one-to-one and adapted to the second limiting grooves.

2. The shock absorber according to claim 1, characterized in that The first limiting bosses are evenly distributed on the lower surface of the upper limiting plate along the axial direction of the shock absorber.

3. The shock absorber according to claim 1, characterized in that The second limiting bosses are evenly distributed on the upper surface of the bottom along the axial direction of the shock absorber.

4. The vibration absorber according to claim 1, characterized in that: The first limiting boss and the second limiting boss are arranged opposite to each other.

5. The shock absorber according to claim 4, characterized in that The first limiting bosses and the second limiting bosses have the same shape and the same number.

6. The vibration absorber according to claim 5, characterized in that The first limiting boss is in a fan-shaped shape and is distributed along the outer edge of the lower surface of the upper limiting plate.

7. The vibration absorber according to claim 6, characterized in that The number of the first limiting bosses is four, and the included angle of the fan ring is 45°.

8. The vibration absorber according to claim 1, characterized in that The height of the first limiting boss is smaller than the depth of the first groove, and the height of the second limiting boss is smaller than the depth of the second groove.

9. The shock absorber according to any one of claims 1 to 8, characterized in that: The upper rubber pad and the lower rubber pad are made of silicone rubber, and the upper limit plate and the lower limit sleeve are made of stainless steel or titanium alloy.

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