A composite shock absorber with positive and negative stiffness

Abstract

The present invention relates to the technical field of airbag shock absorption, and specifically to a composite shock absorber with positive and negative stiffness, comprising: an airbag; a transition part, located above the airbag, the transition part comprising a first transition part and a second transition part, the second transition part is fixed on the top of the airbag, a platform is fixed above the first transition part, a connecting part is provided between the first transition part and the second transition part, the connecting part is connected to the first transition part or the second transition part through at least one point contact; an adjusting device, arranged along the axial direction of the airbag; a flexible hinge, the two ends of the flexible hinge are respectively connected to the top of the adjusting device and the second transition part, when the instrument is placed on the platform, the first transition part and the second transition part reduce the frequency of the airbag in the horizontal direction through the relative movement of the connecting part.

Description

Technical Field

[0001] The present invention relates to the technical field of airbag shock absorption, and particularly to a composite shock absorber with positive and negative stiffnesses. Background Art

[0002] In the field of vibration control, airbag technology, as an effective shock absorption means, is widely used in various mechanical systems. Traditionally, in order to reduce the natural frequency in the vertical (i.e., perpendicular) direction, people tend to set the airbag in an upright manner. This setting method has indeed achieved remarkable frequency reduction effects in the vertical direction, effectively reducing the impact of vertical vibrations on the mechanical system.

[0003] However, the practice of placing the airbag upright has unsatisfactory performance in the horizontal direction (i.e., lateral or longitudinal). Due to the geometric shape and material properties of the airbag, it is difficult to precisely set its movement characteristics in the horizontal direction when placed upright, resulting in the horizontal vector natural frequency being difficult to reach a smaller ideal value. This means that although the vertical vibrations are effectively controlled, the vibration problems in the horizontal direction are still prominent and cannot meet the higher requirements for vibration control.

[0004] To overcome this problem, researchers have started to explore the possibility of placing the airbag upside down. After the airbag is placed upside down, the effect of reducing the natural frequency in the vertical direction has not changed significantly and still maintains its original effectiveness. This discovery provides strong support for the application of airbag technology in vertical vibration control.

[0005] More importantly, the upside-down airbag shows new potential in the horizontal direction. Compared with the upright airbag, the upside-down airbag can more effectively cope with the influence of low horizontal vector frequencies. This is because placing the airbag upside down changes the force state and vibration mode of the airbag, making it have better shock absorption performance in the horizontal direction. This discovery provides new ideas and methods for optimizing the vibration performance of mechanical systems in the horizontal direction.

[0006] However, it should be noted that although the upside-down airbag has significant shock absorption advantages in the horizontal direction, the inverted pendulum structure itself has instability problems.

[0007] Therefore, the present application has developed a composite shock absorber with positive and negative stiffnesses to solve the problems existing in the prior art. Summary of the Invention

[0008] The object of the present invention is to provide a composite shock absorber with positive and negative stiffnesses to solve the problem that in the prior art, when the airbag reduces the frequency in the vertical vector, it cannot reduce the frequency in the horizontal direction.

[0009] The technical solution of the present invention is: a composite shock absorber with positive and negative stiffnesses, comprising:

[0010] an airbag;

[0011] A transfer part, located above the airbag, the transfer part includes a first transfer member and a second transfer member, the second transfer member is fixed to the top of the airbag, a platform is fixed above the first transfer member, a connecting member is provided between the first transfer member and the second transfer member, and the connecting member is in contact connection with the first transfer member or the second transfer member through at least one point;

[0012] An adjusting device, arranged along the axial direction of the airbag;

[0013] A flexible hinge, both ends of the flexible hinge are respectively connected to the top of the adjusting device and the second transfer member. When the instrument is placed on the platform, the first transfer member and the second transfer member reduce the frequency of the airbag in the horizontal direction through the relative movement of the connecting member.

[0014] Preferably, the first transfer member has a concave first arc surface, the first arc surface is located on the side of the first transfer member adjacent to the second transfer member, the connecting member is fixed on the second transfer member and is set as a spherical surface protruding relative to the second transfer member, and the spherical surface is in point contact with the concave arc surface.

[0015] Preferably, the adjacent surfaces of the first transfer member and the second transfer member are symmetrically provided with concave second arc surfaces, the connecting member is spherical and is in point contact with both second arc surfaces respectively.

[0016] Preferably, the adjacent surfaces of the first transfer member and the second transfer member are respectively provided with a concave third arc surface and a round table surface opposite to the third arc surface, the connecting member is spherical, is in line contact with the round table surface respectively, and is in point contact with the third arc surface. There are three round table surfaces and third arc surfaces respectively, and they are arranged in an arc array with the center of the first transfer member as the center of the circle.

[0017] Preferably, the adjacent surfaces of the first transfer member and the second transfer member are symmetrically provided with multiple groups of concave fourth arc surfaces, the connecting member is spherical and is in point contact with multiple groups of fourth arc surfaces respectively, and multiple groups of fourth arc surfaces are arranged in an arc array with the center of the first transfer member as the center of the circle.

[0018] Preferably, the flexible hinge includes a first elastic part, a second elastic part and a connecting block. The first elastic part and the second elastic part are sequentially connected through the connecting block to form a strip shape, and the first elastic part and the second elastic part deform in two directions.

[0019] Preferably, the adjusting device includes a fixed column, a third elastic part, a supporting part, a sliding part and a rotating part. The two supporting parts are connected to both ends of the third elastic part. The supporting part located at the top of the third elastic part is connected to the second adapter through the flexible hinge. The sliding part is slidably arranged on the third elastic part and is fixedly connected to the rotating part. The rotating part is rotatably connected to the fixed column. When the rotating part rotates, it drives the sliding part to slide on the third elastic part, thereby changing the relative distance between the upper surface of the sliding part and the lower surface of the supporting part of the third elastic part.

[0020] Preferably, the third elastic part includes two leaf springs. Both ends of the two leaf springs are respectively fixed on the supporting part. The sliding part includes a second connecting block located between the two leaf springs, and a first connecting block and a third connecting block located on both sides of the second connecting block. The first connecting block and the third connecting block are both attached to the second connecting block and locked by screws. Among them, on the contact surfaces of the first connecting block and the second connecting block, they each extend towards each other to jointly form two first extension parts. On the contact surfaces of the second connecting block and the third connecting block, they each extend towards each other to jointly form two second extension parts, so as to define a sliding space corresponding to the two leaf springs.

[0021] Preferably, notch openings are provided on both the upper surface and the lower surface of the second connecting block. The first connecting block and the third connecting block both extend towards the second connecting block and are respectively located in the corresponding notch openings.

[0022] Preferably, the rotating part includes a first gear and a second gear. The first gear is rotatably connected to the fixed column. The second gear is fixedly connected to one side of the locked first connecting block, second connecting block and third connecting block, and meshes with the first gear.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] (1) An inverted pendulum structure is formed by the airbag and the adapter to provide buffering in the vertical direction, and due to the characteristics of the positive stiffness of the flexible hinge, the vibration energy in the vertical and horizontal directions is effectively absorbed and dispersed, significantly reducing the vibration frequency of the shock absorber in the horizontal direction and improving the stability and accuracy of the instrument;

[0025] (2) The connection method (such as point contact, line contact) between the first adapter and the second adapter allows a certain degree of relative movement while maintaining the overall stability of the structure. It can not only reduce the influence of the relative displacement caused by vibration on the airbag, but also maintain the stability of the airbag when subjected to external forces. At the same time, the limit position is limited by the arc surface or frustum surface provided on the first adapter to reduce the horizontal vibration transmitted to the airbag;

[0026] (3) The elastic characteristics of the flexible hinge in two directions can accurately determine the moving angle of the airbag in the horizontal direction, ensuring the stable movement of the airbag in a specific direction, thereby improving the overall accuracy and stability of the instrument;

[0027] (4) By designing the extension parts and notches between the first connecting block, the second connecting block and the third connecting block, the connection strength between the connecting blocks is increased, preventing them from scattering when removing the screws;

[0028] (5) Through the rotating part (including the first gear and the second gear), the position of the sliding part on the elastic part can be conveniently adjusted, and the relative distance between the upper surface of the sliding part and the lower surface of the supporting part can be adjusted according to actual needs, thereby changing the stiffness of the elastic part to meet the stiffness requirements of different precision machinery. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the drawings and embodiments:

[0030] Figure 1a It is a side sectional view of the adapter corresponding to the first embodiment of the present invention;

[0031] Figure 1b It is a side sectional view of the adapter corresponding to the second embodiment of the present invention;

[0032] Figure 1c It is a side sectional view of the adapter corresponding to the third embodiment of the present invention;

[0033] Figure 1d It is a side sectional view of the adapter corresponding to the fourth embodiment of the present invention;

[0034] Figure 1e It is a side sectional view of the adapter corresponding to the fifth embodiment of the present invention;

[0035] Figure 2 It is an exploded view of the adapter of the fourth embodiment of the present invention;

[0036] Figure 3 It is a structural schematic diagram of a composite shock absorber with positive and negative stiffness of the present invention;

[0037] Figure 4 It is a structural schematic diagram of the flexible hinge of the present invention;

[0038] Figure 5 It is a top view of the assembly of the flexible hinge and the airbag of the present invention;

[0039] Figure 6 It is a structural schematic diagram of the adjusting device of the present invention;

[0040] Figure 7Explosion schematic diagram of the sliding part described in the present invention;

[0041] Figure 8 Structural schematic diagram of the sliding part described in the present invention;

[0042] Figure 9a First horizontal frequency simulation result diagram under the same time condition when the airbag is not installed with the adapter;

[0043] Figure 9b Second horizontal frequency simulation result diagram under the same time condition when the airbag is not installed with the adapter;

[0044] Figure 10a First horizontal frequency simulation result diagram of the shock absorber under the same time condition when the diameter of the connecting piece is 40 mm in the first embodiment of the present invention;

[0045] Figure 10b Second horizontal frequency simulation result diagram of the shock absorber under the same time condition when the diameter of the connecting piece is 40 mm in the first embodiment of the present invention;

[0046] Figure 11a First horizontal frequency simulation result diagram of the shock absorber under the same time condition when the diameter of the connecting piece is 50 mm in the first embodiment of the present invention;

[0047] Figure 11b Second horizontal frequency simulation result diagram of the shock absorber under the same time condition when the diameter of the connecting piece is 50 mm in the first embodiment of the present invention;

[0048] Figure 12a First horizontal frequency simulation result diagram of the shock absorber under the same time condition in the fourth embodiment of the present invention;

[0049] Figure 12b Second horizontal frequency simulation result diagram of the shock absorber under the same time condition in the fourth embodiment of the present invention.

[0050] Wherein: 1. Airbag;

[0051] Adapter; 21. First adapter; 22. Second adapter; 23. Connecting piece; 231. Spherical surface; 24. First arc surface; 25. Second arc surface; 26. Third arc surface; 27. Conical surface; 28. Fourth arc surface;

[0052] Adjusting device; 31. Fixed column; 32. Third elastic part; 321. Leaf spring; 33. Supporting part; 34. Sliding part; 341. First connecting block; 342. Second connecting block; 343. Third connecting block; 344. First extension part; 345. Second extension part; 346. Notch; 35. Rotating part; 351. First gear; 352. Second gear.

[0053] 4. Flexible hinge; 41. First elastic part; 42. Second elastic part; 43. Connecting part. DETAILED DESCRIPTION

[0054] The present invention is further described in detail below in conjunction with specific embodiments:

[0055] As shown in Figure 1- Figure 3 As shown, a composite shock absorber with positive and negative stiffness includes an airbag 1, an adapter 2, an adjustment device 3 and a flexible hinge 4. The airbag 1 serves as a shock-absorbing foundation, provides vertical buffering, and is placed inverted. The bottom of the airbag 1 contacts the base platform and can swing in any direction. The bottom of the airbag 1 forms a hinge-like structure, and the adapter 2 is located on the top of the airbag 1, including a first adapter 21 and a second adapter 22. The second adapter 22 is fixed to the top of the airbag 1, and a platform is fixed above the first adapter 21 for placing instruments. A connecting member 23 is provided between the first adapter 21 and the second adapter 22, and the connecting member 23 is connected to the adapter by at least one point contact, thereby realizing a rigorous inverted pendulum structure, and the inverted pendulum structure is a negative stiffness structure, wherein the two ends of the flexible hinge 4 are respectively connected to the second adapter 22 and the adjusting device 3, and the airbag 1 is connected to one end of the flexible hinge 4 and fixed by the adjusting device 3, and the flexible hinge 4 is a positive stiffness structure, and the parallel connection of positive and negative stiffness is realized by the parallel connection of the inverted pendulum structure and the flexible hinge 4, so as to reduce the vibration frequency of the shock absorber in the horizontal direction, and effectively absorb and disperse the vibration energy in the vertical and horizontal directions. At the same time, the adjusting device 3 includes a fixed column 31, a third elastic part 32, a supporting part 33, a sliding part 34 and a rotating part 35, and the sliding part 34 slides on the third elastic part 32 to realize the stiffness adjustment function of the third elastic part 32 to adapt to the stiffness requirements of different instruments. Embodiment 1:

[0056] like Figure 1a As shown, a first arcuate surface 24 is provided on a surface adjacent to the first adapter 21 and the second adapter 22, and a corresponding connecting member 23 is fixedly arranged on the second adapter 22, and protrudes as a spherical surface 231 relative to the second adapter 22, and the spherical surface 231 is in point contact with the first arcuate surface 24, and the diameter of the spherical surface 231 is smaller than the diameter of the first arcuate surface 24, so that there is a certain relative movement between the first adapter 21 and the second adapter 22, so that the connecting member 23 forms a "hinge" connection between the first adapter 21 and the second adapter 22, and forms an inverted pendulum structure together with the airbag 1, and the diameter of the spherical surface 231 is smaller than the diameter of the first arcuate surface 24, which means that the movement range of the spherical surface 231 within the arcuate surface is limited, and when there is horizontal vibration, the stability of the inverted pendulum structure within a certain range can be guaranteed. Embodiment 2:

[0057] As Figure 1b shown, on the adjacent surfaces of the first adapter 21 and the second adapter 22, concave second arc surfaces 25 are symmetrically arranged. The connecting member 23 is spherical and is in point contact with the two second arc surfaces 25 respectively. The design of point contact allows a certain degree of relative movement freedom between the first adapter 21 and the second adapter 22, which helps to reduce the relative displacement directly transmitted to the airbag 1 due to vibration, resulting in a large horizontal offset of the airbag 1. When the connecting part 2 is stressed and vibrates, the spherical connecting member 23 can roll freely within the second arc surface 25, thus effectively reducing vibration transmission and improving the shock absorption effect. Moreover, the symmetrically arranged second arc surfaces 25 make the forces on the first adapter 21 and the second adapter 22 in the horizontal direction more uniform, reducing the sliding friction force generated due to excessive local stress, reducing the wear between the first adapter 21 and the second adapter 22, and reducing the influence of vibration on the airbag 1 in the horizontal direction, ensuring the accuracy and reliability during the working process. Embodiment Three:

[0058] As Figure 1c shown, on the adjacent surfaces of the first adapter 21 and the second adapter 22, a concave third arc surface 26 and a conical surface 27 opposite to the third arc surface 26 are respectively arranged. The connecting member 23 is spherical and is in line contact with the conical surface 27 and in point contact with the third arc surface 26. The design of the line contact between the spherical connecting member 23 and the conical surface 27 allows a certain degree of relative sliding freedom of the connecting member 23 in the horizontal direction, enabling the first adapter 21 to offset different angles and distances relative to the second adapter 22. The specific rotation angle is within 0° - 2°, maintaining the stability within this range. Moreover, the design of the line contact between the conical surface 27 and the spherical connecting member 23 can more effectively disperse and bear forces from different directions. Embodiment Four:

[0059] As Figure 1dAs shown in the figure, on the adjacent surfaces of the first adapter 21 and the second adapter 22, concave third arc surfaces 26 and round table surfaces 27 opposite to the third arc surfaces 26 are respectively provided. Both the round table surfaces 27 and the third arc surfaces 26 are three in number, and are arranged in an arc array with the center of the first adapter 21 as the center of the circle. The connecting member 23 is spherical, and is in line contact with the round table surface 27 and in point contact with the third arc surface 26 respectively. When the connecting member 23 is subjected to vibration, the spherical connecting member 23 can freely roll or move slightly within the round table surface 27 and the third arc surface 26, thereby effectively dispersing and absorbing the vibration energy. At the same time, the three connecting members 23 are correspondingly located between the three third arc surfaces 26 and the round table surfaces 27, which can achieve the function of automatic leveling, ensure good contact between the connecting member 23 and the arc surface and the round table surface 27, and reduce the wear caused by friction. At the same time, a rigid element is provided above the first adapter 21, which is rigidly supported in the horizontal direction. Through the design of multiple spherical connecting members 23, the influence of the rigid support on the horizontal frequency can be avoided. Embodiment Five:

[0060] As Figure 1e shown in the figure, three groups of concave fourth arc surfaces 28 are symmetrically arranged on the adjacent surfaces of the first adapter 21 and the second adapter 22. The connecting member 23 is spherical and is in point contact with both of the two second arc surfaces 25 respectively, which helps to achieve a smoother and more continuous control effect during the movement of the inverted pendulum, and reduces the problems of discontinuous movement or jitter caused by excessive rigidity of the connecting part.

[0061] It should be noted that in Embodiment One, Embodiment Three, Embodiment Four, and Embodiment Five, the bottom of the airbag 1 is in contact with the base platform. When the instrument is placed on the platform and exerts pressure on the airbag 1, at this time, the airbag 1 can swing in any direction, thus forming a structure similar to a hinge. The first adapter 21 and the second adapter 22 provided at the top of the airbag 1 are respectively in contact with the connecting member 23 and at least have one point contact, thereby forming an inverted pendulum structure. Among them, the connecting member 23 is not fixed to the first adapter 21 and the second adapter 22, forming a free hinge, so that the first adapter 21 and the second adapter 22 move relatively on the connecting member 23. The arc surface or the round table surface 27 provided on the first adapter 21 restricts the movement of the first adapter 21. The angle at which the first adapter 21 can rotate and move is 0° to 2°, and the first adapter 21 in the limit state is limited to prevent excessive movement from causing obvious horizontal vibration to the airbag 1, while the slight offset reduces the horizontal vibration transmitted to the airbag 1, thereby being able to reduce the horizontal frequency.

[0062] Furthermore, the second adapter 22 is connected to the flexible hinge 4, and the flexible hinge 4 is fixed to the adjusting device 3. Through the flexible hinge 4, the adjusting device 3 and the adapter part 2, the horizontal frequency is further reduced, and it can adapt to more different and complex instrument requirements.

[0063] In the second embodiment, there is only one spherical connector 23, and the diameter of the connector is small, so that the adapter part 2 and the airbag 1 form a strict inverted pendulum structure, which cannot reduce the frequency in the horizontal direction. Therefore, both ends of the flexible hinge 4 are respectively connected to the second adapter 22 and the adjusting device 3, so as to reduce the frequency in the horizontal direction through the cooperation of the flexible hinge 4 and the adjusting device 3.

[0064] For further illustration, in the first embodiment, the second embodiment, the third embodiment, the fourth embodiment and the fifth embodiment, after the adapter part 2 is installed, during the shock absorption process, the adapter part 2 only restricts the horizontal vibration, and the inverted pendulum structure only restricts the vertical vibration, and neither restricts the relative rotation. Only the inverted pendulum structure contacts the upper platform, and other structures do not contact, so that the shock absorber can not only achieve the shock absorption effect, but also make the reduction effect of the horizontal frequency better.

[0065] According to Figure 9a and Figure 9b shown, when the adapter part 2 is not installed on the airbag 1, its horizontal frequency is 3.5 Hz. After the adapter part 2 is installed, as Figure 10a and Figure 10b shown, when the diameter of the connector 23 in the first embodiment is 40 mm, the horizontal frequency of the corresponding shock absorber is about 1.5 Hz. Another example is as Figure 11a and Figure 11b shown, when the diameter of the connector 23 in the first embodiment is 50 mm, the horizontal frequency of the corresponding shock absorber is significantly higher than that when the diameter of the connector 23 is 40 mm. From this, it can be concluded that when the diameter of the connector 23 gradually decreases, the horizontal frequency also gradually decreases; as Figure 12a and Figure 12b shown, the simulation diagram of the horizontal frequency of the shock absorber in the fourth embodiment is compared with Figure 9a and Figure 9b to obtain that it can slightly reduce the horizontal frequency of the shock absorber.

[0066] As Figures 4 - 5 shown, the flexible hinge 4 includes a first elastic part 41 and a second elastic part 42, and is sequentially connected into a long strip shape through a connecting part 43. When the airbag 1 is subjected to an external force, the first elastic part 41 and the second elastic part 42 of the flexible hinge 4 will deform. Also due to the elastic characteristics of the flexible hinge 4, it can return to the original state after the external force is withdrawn, so as to achieve the shock absorption effect, and the flexible hinge 4 can also effectively control the moving angle of the airbag 1 in the horizontal direction to ensure the stable movement of the airbag 1 in a specific direction.

[0067] Furthermore, the first elastic part 41 and the second elastic part 42 are arranged perpendicular to each other and deform in two mutually perpendicular directions. Since the first elastic part 41 and the second elastic part 42 deform in two perpendicular directions respectively, when the airbag 1 is subjected to an external force, no matter from which direction the external force comes, the flexible hinge 4 can limit the displacement of the airbag 1 in the horizontal direction through the deformation of its two elastic parts, thereby improving the overall accuracy and stability of the instrument.

[0068] Specifically, in the present application, both the first elastic part 41 and the second elastic part 42 are formed by two leaf springs arranged oppositely. The flexible hinge 4 transmits the horizontal displacement to the leaf spring structure, thereby achieving the effect of parallel connection of positive and negative stiffness of the horizontal leaf spring and the airbag 1; at the same time, the flexible hinge 4 also decouples the movement of the support on the top of the airbag 1, isolating factors such as bending moment and vertical displacement that affect the stiffness of the leaf spring, so that the force transmitted to the leaf spring is perpendicular to the surface of the leaf spring. Further, the two leaf spring structures are placed at 90°, and through force decomposition, parallel connection of positive and negative stiffness of the airbag 1 in the horizontal direction (transverse and longitudinal) can be achieved, and the setting of the two flexible hinges 4 can further share the received vibration, thereby reducing the frequency in the horizontal direction.

[0069] As Figures 6 - 8 shown, the third elastic part 32 includes two leaf springs 321, and the two ends of the two leaf springs 321 are respectively fixed on the corresponding support parts 33. The sliding part 34 includes a first connecting block 341, a second connecting block 342 and a third connecting block 343. Among them, the second connecting block 342 is located between the two leaf springs 321, and the first connecting block 341 and the third connecting block 343 are respectively located on both sides of the second connecting block 342 and are in close contact with the second connecting block 342. The three connecting blocks are locked by screws to prevent the sliding part 34 from slipping when the third elastic part 32 reduces the influence of the horizontal vector frequency on the airbag 1 through deformation, resulting in a change in the stiffness of the third elastic part 32, so that the influence of the current horizontal vector frequency on the precision machinery cannot be reduced. When the rotating part 35 rotates, it drives the sliding part 34 to slide on the third elastic part 32, thereby changing the relative distance between the upper surface of the sliding part 34 and the lower surface of the support part 33 of the third elastic part 32, thereby changing the deformation length of the third elastic part 32, and further changing the stiffness of the third elastic part 32 to meet the stiffness requirements of different precision machinery.

[0070] As Figures 7 - 8As shown, to prevent the first connecting block 341, the second connecting block 342, and the third connecting block 343 from directly falling apart when removing the screw while adjusting the position of the sliding part 34, on the contact surfaces between the first connecting block 341 and the second connecting block 342, they extend towards each other, jointly forming two first extension parts 344. On the contact surfaces between the second connecting block 342 and the third connecting block 343, they extend towards each other respectively, jointly forming two second extension parts 345 to define the sliding spaces for the corresponding two leaf springs 321. Moreover, notches 346 are formed on the upper and lower surfaces of the second connecting block 342. The first connecting block 341 and the third connecting block 343 both extend towards the second connecting block 342 and extend into the corresponding notches 346. The notches 346 formed on the upper and lower surfaces of the second connecting block 342 provide accommodation spaces for the extended parts of the first connecting block 341 and the third connecting block 343, enabling mutual restraint between the connecting blocks in the vertical direction, further preventing them from falling. The first connecting block 341 and the third connecting block 343 both extend towards the second connecting block 342 and extend into the corresponding notches 346, which not only increases the connection strength between the connecting blocks but also makes them not easily fall apart when removing the screw.

[0071] To more precisely control the position of the sliding part 34 on the third elastic part 32, the rotating part 35 includes a first gear 351 and a second gear 352. The first gear 351 is rotatably connected to the fixed column 31. The second gear 352 meshes with the first gear 351. The second gear 352 is fixedly connected to one side of the locked first connecting block 341, second connecting block 342, and third connecting block 343. When the first gear 351 rotates, the second gear 352 moves up and down, driving the sliding part 34 to move, thereby completing the adjustment of the stiffness of the third elastic part 32.

[0072] Specifically, both the first gear 351 and the second gear 352 are herringbone gears. The unique tooth shape of the herringbone gear can more evenly distribute the load on the teeth, thus significantly enhancing the load-bearing capacity of the gear and helping to compensate for slight misalignments, preventing the first gear 351 from moving axially along itself and being misaligned with the second gear 352 when rotating, which would affect the stiffness of the corresponding elastic part after the adjustment of the sliding part 34.

[0073] The above embodiments are only used to illustrate the technical concept and features of the present invention. The purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes that fall within the meaning and scope of the equivalent elements of the claims within the present invention.

Claims

1. A composite shock absorber with positive and negative stiffness, characterized in that: include: Airbag (1); an adapter part (2) located above the airbag (1), the adapter part (2) comprising a first adapter part (21) and a second adapter part (22), the second adapter part (22) being fixed to the top of the airbag (1), a platform being fixed above the first adapter part (21) for placing instruments, a connecting part (23) being provided between the first adapter part (21) and the second adapter part (22), the connecting part (23) being connected to the first adapter part (21) or the second adapter part (22) by at least one point contact; An adjusting device (3) is arranged along the axial direction of the airbag (1), the adjusting device (3) comprising a third elastic portion (32) and a sliding portion (34), and the sliding portion (34) slides on the third elastic portion (32) to achieve a stiffness adjustment function of the third elastic portion (32) to meet the stiffness requirements of different instruments; A flexible hinge (4), wherein two ends of the flexible hinge (4) are respectively connected to the top of the adjustment device (3) and the second adapter (22); when the instrument is placed on the platform, the first adapter (21) and the second adapter (22) reduce the frequency of the airbag (1) in the horizontal direction through the relative movement of the connecting member (23); the flexible hinge (4) comprises a first elastic portion (41), a second elastic portion (42) and a connecting portion (43); the first elastic portion (41) and the second elastic portion (42) are connected in sequence through the connecting portion (43) to form a long strip, and the first elastic portion (41) and the second elastic portion (42) are deformed in two directions.

2. A positive and negative stiffness composite shock absorber according to claim 1, characterized in that: The first adapter (21) has a concave first arcuate surface (24), the first arcuate surface (24) being located on a surface of the first adapter (21) adjacent to the second adapter (22), the connecting member (23) being fixed to the second adapter (22) and being arranged as a spherical surface (231) protruding relative to the second adapter (22), the spherical surface (231) being in point contact with the concave arcuate surface.

3. A positive and negative stiffness composite shock absorber according to claim 1, characterized in that: A concave second arc-shaped surface (25) is symmetrically arranged on one side adjacent to the first adapter (21) and the second adapter (22); the connecting member (23) is spherical and is in point contact with the two second arc-shaped surfaces (25).

4. A positive and negative stiffness composite shock absorber according to claim 1, characterized in that: A concave third arcuate surface (26) and a truncated cone surface (27) opposite to the third arcuate surface (26) are respectively provided on adjacent surfaces of the first adapter (21) and the second adapter (22); the connecting member (23) is spherical and is in line contact with the truncated cone surface (27) and in point contact with the third arcuate surface (26); a plurality of truncated cone surfaces (27) and a plurality of third arcuate surfaces (26) are provided and are arranged in an arc array with the center of the first adapter (21) as the center of the circle.

5. The positive and negative stiffness composite shock absorber according to claim 1, characterized in that: A plurality of groups of inwardly concave fourth arcuate surfaces (28) are symmetrically arranged on a surface adjacent to the first adapter (21) and the second adapter (22); the connecting member (23) is spherical and is in point contact with the plurality of groups of the fourth arcuate surfaces (28); and the plurality of groups of the fourth arcuate surfaces (28) are arranged in an arc array with the center of the first adapter (21) as the center of the circle.

6. The positive and negative stiffness composite shock absorber according to claim 1, characterized in that: The adjusting device (3) comprises a fixed column (31), a supporting portion (33), and a rotating portion (35); the two supporting portions (33) are connected to two ends of the third elastic portion (32); the supporting portion (33) located at the top of the third elastic portion (32) is connected to the second adapter (22) via the flexible hinge (4); the sliding portion (34) is slidably arranged on the third elastic portion (32) and is fixedly connected to the rotating portion (35); the rotating portion (35) is rotatably connected to the fixed column (31); when the rotating portion (35) rotates, the sliding portion (34) is driven to slide on the third elastic portion (32), thereby changing the relative distance between the upper surface of the sliding portion (34) and the lower surface of the supporting portion (33) of the third elastic portion (32).

7. A positive and negative stiffness composite shock absorber according to claim 6, characterized in that: The third elastic portion (32) comprises two leaf springs (321), the two ends of the two leaf springs (321) are respectively fixed on the supporting portion (33), the sliding portion (34) comprises a second connecting block (342) located between the two leaf springs (321) and a first connecting block (341) and a third connecting block (343) located on both sides of the second connecting block (342), the first connecting block (341) and the third connecting block (343) both being attached to the second connecting block (342) and being screwed; wherein the contact surfaces of the first connecting block (341) and the second connecting block (342) respectively extend towards each other to form two first extension portions (344), and the contact surfaces of the second connecting block (342) and the third connecting block (343) respectively extend towards each other to form two second extension portions (345) to define a sliding space corresponding to the two leaf springs (321).

8. A positive and negative stiffness composite shock absorber according to claim 7, characterized in that: The upper surface and the lower surface of the second connection block (342) are both provided with notches (346), and the first connection block (341) and the third connection block (343) both extend toward the second connection block (342) and are respectively located in the corresponding notches (346).

9. A positive and negative stiffness composite shock absorber according to claim 6, characterized in that: The rotating part (35) comprises a first gear (351) and a second gear (352), wherein the first gear (351) is rotatably connected to the fixed column (31), and the second gear (352) is fixedly connected to one side of the locked first connecting block (341), the second connecting block (342) and the third connecting block (343), and meshes with the first gear (351).

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