Viscous damper with adjustable rigidity

Abstract

The utility model relates to a viscous damper with adjustable rigidity, which is characterized in that a first spiral spring is connected between a first adjusting nut and a first sealing device in series, the first spiral spring is in surface contact with the first adjusting nut, and the first spiral spring is in surface contact with the first sealing device; the first adjusting nut can adjust the compression length of the first spiral spring through threads of the piston rod, the change of the compression length of the first spiral spring means the change of the initial rigidity of the spring, and certain rigidity can be provided for the whole building under small wind vibration and small earthquakes to resist the effect of external loads. According to the product, under large wind vibration and large earthquakes, the whole building deforms, and energy is dissipated through the damping effect of the viscous damper; the product can recover to the original performance after energy consumption, and the range of energy consumption starting force of the product is wider.

Description

Technical Field

[0001] The utility model relates to the field of viscous dampers, in particular to a viscous damper with adjustable stiffness. Background Art

[0002] Viscous dampers are widely used in construction, bridges, aerospace, aviation, military industry, weapons, automobiles, industrial equipment and other industries due to their excellent energy dissipation capacity. The working principle is: when the piston moves back and forth inside the cylinder, the viscous fluid material flows from the pressurized cavity to the non-pressurized cavity through the annular gap between the piston and the cylinder or the hole on the piston. In this process, the fluid's along-the-path resistance produces energy dissipation and the pore shrinkage resistance produces energy dissipation, thereby realizing the energy dissipation effect of the viscous damper. The energy dissipation effect of the viscous damper is related to the speed of the piston movement, so the viscous damper is also called a velocity-dependent damper, which has the characteristics of high damping efficiency and extremely small static stiffness.

[0003] For excellent earthquake-resistant structures: under small wind vibrations and small earthquakes, it can provide a certain rigidity for the whole building to resist the effects of external loads and avoid internal damage to the structure; under large wind vibrations and large earthquakes, the whole building deforms, and the damping effect of the damper is needed to dissipate energy to avoid serious damage or even collapse of the structure. This requires us to provide a damper that has both rigidity and energy dissipation. Although metal dampers can achieve this function, they have the following disadvantages: 1. The performance of metal dampers will undergo an irreversible change after yielding and consuming energy, and they need to be replaced and maintained after the earthquake, which is very uneconomical; 2. The yield stress of metal energy-absorbing materials manufactured by existing process technology is relatively small relative to the required range of the structure under large wind vibrations and large earthquakes, and the optional range of the product's energy-absorbing starting force is narrow; 3. The pre-yield stiffness and post-yield stiffness of metal dampers are fixed and cannot be flexibly adjusted. The present invention provides a product which is a viscous damper with a certain stiffness. After consuming energy, the product can recover to its original performance. The range of energy consumption starting force of the product is wider than that of the metal damper, and the stiffness can be flexibly adjusted. It can perfectly combine the advantages of the metal damper and the viscous damper.

[0004] For equipment vibration reduction and isolation: the production process of high-precision products, medical surgery process, and precision testing process have very strict requirements for vibration reduction and isolation in the working environment. In order to meet the vibration reduction and isolation requirements of the production system, the characteristic frequency of the damper must be staggered with the resonant frequency domain of the input excitation of the equipment vibration, and the characteristic frequency of the damper must be staggered with the characteristic frequency of the entire working system. Then, the vibration that is not completely isolated will be completely dissipated through the energy dissipation of the damper, and the requirements of a vibration-free or micro-vibration working environment have been achieved; according to the inherent characteristic frequency equation in vibration dynamics, it is known that assuming the inherent characteristic frequency of the production system is Assume that the natural characteristic frequency of the damper is However, the load on the devices in the system is not constant during operation, and the operating vibration frequency is also not constant. Suppose the personnel and the stacked materials on the operating platform will also change according to production needs, that is, k1 and m1 will change. During the actual vibration isolation and reduction process, the total weight m2 of the damper remains fixed. To stagger the new natural frequency ω1 of the production system, at this time, we require that the damper product can flexibly adjust the stiffness k1 to meet the requirements of the new vibration isolation state. The present invention provides a product which is a viscous damper with a certain stiffness and the stiffness can be flexibly adjusted, which can not only isolate vibration but also dissipate vibration energy.

[0005] The invention patent application with the authorization announcement number CN 104033528 A discloses an automobile shock absorber. The hydraulic shock absorber (viscous damper) includes a piston rod in a piston cylinder. A ring-shaped support block is sleeved inside each of the two mounting rings at both ends of the hydraulic shock absorber (viscous damper). The edge of the support block is provided with a protrusion, and a spring is sleeved outside the hydraulic shock absorber between the two support blocks. This invention can solve the problems of insufficient shock absorption strength and unstable buffering process of the existing automobile shock absorbers. However, the application scenarios and application requirements of this invention patent are different from those of building vibration isolation and reduction and equipment vibration isolation and reduction, and there are obvious disadvantages as follows: 1. The spring of the automobile shock absorber only provides stiffness to the damper when it is compressed, resulting in an imbalance in the tensile and compressive stiffness of the damper. Building vibration isolation and reduction and equipment vibration isolation and reduction require balanced tensile and compressive stiffness; 2. The viscous damper of the automobile shock absorber belongs to a single-rod viscous damper, and the magnitudes of the tensile and compressive damping forces of the damper are asymmetric. Building vibration isolation and reduction and equipment vibration isolation and reduction require balanced tensile and compressive damping forces; 3. The initial stiffness of the spring of the automobile shock absorber is fixed and cannot be flexibly adjusted. Summary of the Utility Model

[0006] The purpose of the present utility model is to overcome the deficiencies of the prior art, meet the actual needs, and provide a viscous damper with adjustable stiffness to solve the following technical problems: 1. The spring of the automobile shock absorber only provides stiffness to the damper when it is compressed, resulting in an imbalance in the tensile and compressive stiffness of the damper. Building vibration isolation and reduction and equipment vibration isolation and reduction require balanced tensile and compressive stiffness; 2. The viscous damper of the automobile shock absorber belongs to a single-rod viscous damper, and the magnitudes of the tensile and compressive damping forces of the damper are asymmetric. Building vibration isolation and reduction and equipment vibration isolation and reduction require balanced tensile and compressive damping forces; 3. The initial stiffness of the spring of the automobile shock absorber is fixed and cannot be flexibly adjusted.

[0007] To achieve the object of the present utility model, the technical solution adopted by the present utility model is as follows: Design a viscous damper with adjustable stiffness, including a rod-end spherical bearing, a first adjusting nut, a first helical spring, a first sealing device, a cylinder barrel, a piston, a piston rod, a second sealing device, a second helical spring, a second adjusting nut, an ear plate, viscous damping fluid, damping holes, and an annular gap. A first helical spring is inserted between the first adjusting nut and the first sealing device. The first helical spring is in surface contact with the first adjusting nut and the first sealing device. The first adjusting nut can adjust the compression length of the first helical spring through the thread of the piston rod. The change in the compression length of the first helical spring means the change in the initial stiffness of the spring;

[0008] A second helical spring is inserted between the second adjusting nut and the second sealing device. The second helical spring is in surface contact with the second adjusting nut and the second sealing device. The second adjusting nut can adjust the compression length of the second helical spring through the thread of the piston rod. The change in the compression length of the second helical spring means the change in the initial stiffness of the spring.

[0009] Preferably, the rod-end spherical bearing is connected to the piston rod in a threaded form. The piston rod passes through the first sealing device and the second sealing device and is connected to the piston, and can drive the piston to move back and forth along the axial direction.

[0010] Preferably, the ear plate is connected to the cylinder barrel in a threaded form. The piston rod and the ear plate are respectively fixed on two relatively moving planes. When the building generates relative displacement between two planes due to an earthquake, or when the equipment vibrates to generate relative displacement between two planes, the piston rod drives the piston to move back and forth along the axial direction.

[0011] Preferably, viscous damping fluid is provided between the piston rod and the cylinder barrel. Damping holes are formed outside the piston. An annular gap is formed between the piston and the cylinder barrel. The viscous damping fluid is compressed by the piston and flows from the pressurized cavity to the non-pressurized cavity through the damping holes and the annular gap. In this process, energy dissipation is generated by the frictional resistance of the fluid along the way and the orifice constriction resistance, thereby realizing the energy dissipation function of the viscous damper.

[0012] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0013] 1. The present utility model can provide a certain stiffness for the overall building under small wind vibrations and small earthquakes to resist the action of external loads; under large wind vibrations and large earthquakes, the overall building deforms, and the damping effect of the viscous damper dissipates energy; after the product dissipates energy, it can return to its original performance, and the energy dissipation starting force range of the product is wider.

[0014] 2. According to the inherent characteristic frequency equation in vibration mechanics, it is assumed that the inherent characteristic frequency of the production system is It is assumed that the inherent characteristic frequency of the damper is However, the load of the equipment in the system is not constant during operation, and the operating vibration frequency is not constant either. It is assumed that the personnel and the piled materials on the operating platform will also change according to the production needs, that is, k1 and m1 will change. During the actual vibration isolation process, the total weight m2 of the damper remains fixed. In order to stagger the new inherent frequency ω1 of the production system, the present invention can flexibly adjust the stiffness k1 to adapt to the new vibration isolation state requirements, and the original damping energy dissipation function of the viscous damper can consume the unisolated vibration energy.

[0015] 3. The tension and compression stiffness of the present utility model is completely symmetric with the magnitude and movement trend of the tension and compression damping force, meeting the requirements of building vibration isolation and equipment vibration isolation. Brief Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the first internal structure of the present utility model;

[0017] Figure 2 It is a schematic diagram of the second internal structure of the present utility model;

[0018] Figure 3 It is a schematic diagram of the viscous damping liquid, damping holes and annular gaps of the present utility model.

[0019] In the figure: 1. Rod end spherical plain bearing; 2. First adjusting nut; 3. First helical spring; 4. First sealing device; 5. Cylinder barrel; 6. Piston; 7. Piston rod; 8. Second sealing device; 9. Second helical spring; 10. Second adjusting nut; 11. Ear plate; 12. Viscous damping liquid; 13. Damping holes; 14. Annular gap. Detailed Embodiment

[0020] The present utility model will be further described below in conjunction with the drawings and embodiments:

[0021] Embodiment 1: A viscous damper with adjustable stiffness, see Figures 1 to 3, including a rod end spherical plain bearing 1, a first adjusting nut 2, a first helical spring 3, a first sealing device 4, a cylinder barrel 5, a piston 6, a piston rod 7, a second sealing device 8, a second helical spring 9, a second adjusting nut 10, an ear plate 11, a viscous damping fluid 12, a damping hole 13, and an annular gap 14. A first helical spring 3 is inserted between the first adjusting nut 2 and the first sealing device 4. The first helical spring 3 is in surface contact with the first adjusting nut 2 and the first helical spring 3 is in surface contact with the first sealing device 4. The first adjusting nut 2 can adjust the compression length of the first helical spring 3 through the thread of the piston rod 7. The change in the compression length of the first helical spring 3 means a change in the initial stiffness of the spring. A second helical spring 9 is inserted between the second adjusting nut 10 and the second sealing device 8. The second helical spring 9 is in surface contact with the second adjusting nut 10 and the second helical spring 9 is in surface contact with the second sealing device 8. The second adjusting nut 10 can adjust the compression length of the second helical spring 9 through the thread of the piston rod 7. The change in the compression length of the second helical spring 9 means a change in the initial stiffness of the spring. The compression amounts adjusted by the first helical spring 3 and the second helical spring 9 should be the same to ensure that the initial stiffnesses of the two helical springs are the same. The compression amounts of the first helical spring 3 and the second helical spring 9 are flexibly adjusted according to different project requirements so that the initial stiffness of the product meets the actual requirements of specific projects.

[0022] Specifically, refer to Figure 1 , the rod end spherical plain bearing 1 and the piston rod 7 are connected by a threaded type. The piston rod 7 passes through the first sealing device 4 and the second sealing device 8 and is connected to the piston 6, and can drive the piston 6 to move back and forth along the axial direction. When the piston 6 moves from the second sealing device 8 to the first sealing device 4, the compression amount of the first helical spring 3 increases and the compression amount of the second helical spring 9 decreases. When the piston 6 moves from the first sealing device 4 to the second sealing device 8, the compression amount of the second helical spring 9 increases and the compression amount of the first helical spring 3 decreases. With such back and forth movement, the tensile and compressive stiffnesses of the viscous damper are completely symmetrical, meeting the project requirements.

[0023] Furthermore, refer to Figure 2 , the ear plate 11 and the cylinder barrel 5 are connected by a threaded type. The piston rod 7 and the ear plate 11 are respectively fixed on two relatively moving planes. When the building has relative displacement between two planes due to an earthquake, or when the equipment vibrates to cause relative displacement between two planes, the piston rod 7 drives the piston 6 to move back and forth along the axial direction.

[0024] It should be noted that refer to Figure 3, a viscous damping fluid 12 is provided between the piston rod 7 and the cylinder barrel 5. Damping holes 13 are formed outside the piston 6, and an annular gap 14 is formed between the piston 6 and the cylinder barrel 5. The viscous damping fluid 12 is compressed by the piston 6 and flows from the pressurized cavity to the non-pressurized cavity through the damping holes 13 and the annular gap 14. During this process, energy dissipation occurs due to the frictional resistance of the fluid along the way and the orifice constriction resistance, thereby realizing the energy dissipation function of the viscous damper.

[0025] In addition, the components designed in the present utility model are all common standard components or components known to those skilled in the art. Their structures and principles can all be learned by those skilled in the art through technical manuals or obtained through conventional experimental methods. Those skilled in the art can fully implement them without further elaboration. The content protected by the present utility model also does not involve improvements to the internal structure and methods.

[0026] The embodiments disclosed in the present utility model are preferred embodiments, but are not limited thereto. Those of ordinary skill in the art can easily understand the spirit of the present utility model based on the above embodiments and make different extensions and changes. However, as long as they do not depart from the spirit of the present utility model, they are all within the protection scope of the present utility model.

Claims

1. A viscous damper with adjustable stiffness, comprising a rod-end spherical bearing (1), a first adjusting nut (2), a first helical spring (3), a first sealing device (4), a cylinder barrel (5), a piston (6), a piston rod (7), a second sealing device (8), a second helical spring (9), a second adjusting nut (10), an ear plate (11), a viscous damping fluid (12), a damping hole (13), and an annular gap (14), characterized in that A first helical spring (3) is inserted between the first adjusting nut (2) and the first sealing device (4). The first helical spring (3) is in surface contact with the first adjusting nut (2) and in surface contact with the first sealing device (4). The first adjusting nut (2) adjusts the compression length of the first helical spring (3) through the thread of the piston rod (7). A second helical spring (9) is inserted between the second adjusting nut (10) and the second sealing device (8). The second helical spring (9) is in surface contact with the second adjusting nut (10) and in surface contact with the second sealing device (8). The second adjusting nut (10) adjusts the compression length of the second helical spring (9) through the thread of the piston rod (7).

2. The viscous damper with adjustable stiffness according to claim 1, wherein The rod end spherical plain bearing (1) is connected to the piston rod (7) in a threaded form. The piston rod (7) passes through the first sealing device (4) and the second sealing device (8) and is connected to the piston (6), driving the piston (6) to move back and forth along the axial direction.

3. The adjustable stiffness viscous damper according to claim 1, wherein The ear plate (11) is connected to the cylinder barrel (5) in a threaded form. The piston rod (7) and the ear plate (11) are respectively fixed on two relatively moving planes.

4. The adjustable-stiffness viscous damper according to claim 1, wherein A viscous damping fluid (12) is provided between the piston rod (7) and the cylinder barrel (5). A damping hole (13) is formed outside the piston (6). An annular gap (14) is formed between the piston (6) and the cylinder barrel (5).

Images