Friction damper

Abstract

The invention provides a friction damper which comprises a cuboid-shaped shell, a friction plate and a friction plate. The plane friction plate is arranged in the shell, an actuating rod and a limiting rod extend out of the end faces of the two sides, in the length direction of the shell, of the plane friction plate, at least one driver sleeve is arranged on the plane friction plate, and the driver sleeves vertically face the cover plate; the limiting plate is arranged on the inner wall of the bottom of the shell, and the limiting rod penetrates through the limiting plate; the resetting device comprises a first resetting device and a second resetting device, the limiting rod is sleeved with the first resetting device, and the actuating rod is sleeved with the second resetting device; the at least one piezoelectric ceramic driver is arranged on the plane friction plate, the axial direction of the piezoelectric ceramic driver is perpendicular to the inner wall of the bottom of the shell, a sliding mechanism is arranged at the top end of the piezoelectric ceramic driver, and the sliding mechanism is in sliding contact with the inner wall of the cover plate; and the connecting rod is fixedly arranged on the outer surface of the shell. The friction damper provided by the invention has a variable damping function.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of shock-absorbing devices, in particular to a friction damper. BACKGROUND

[0002] A damper is a device used to consume energy, reduce vibration or impact. Existing friction dampers usually show the limitation of fixed damping force and stiffness when dealing with small deformation of the structure, which is difficult to meet the complex shock-absorbing requirements. In addition, these traditional dampers fail to effectively recycle the energy consumed from the outside environment to achieve shock-absorbing, resulting in energy waste. With the development of smart materials and energy recovery technology, there is an urgent need for an innovative friction damper that can provide variable damping and variable stiffness under small deformation conditions while achieving energy recovery, in order to improve the shock-absorbing effect and energy utilization efficiency. SUMMARY

[0003] Therefore, the present application provides a friction damper, which has the following specific structure: a shell in the shape of a cuboid, a cover plate cooperatively arranged on the shell, a planar friction plate arranged in the shell, the planar friction plate being in slidable contact with the inner wall of the bottom of the shell, actuating rods and limiting rods protruding from the two side end faces of the planar friction plate along the length direction of the shell, the actuating rods protruding out of the shell, at least one driver sleeve arranged on the planar friction plate and vertically facing the cover plate, a limiting plate arranged on the inner wall of the bottom of the shell and vertically upward, the limiting rods penetrating through the limiting plate, a reset device including a first reset device and a second reset device, the first reset device being sleeved on the limiting rods and having two ends respectively abutting against the limiting plate and one end face of the planar friction plate, the second reset device being sleeved on the actuating rods and having two ends respectively abutting against one inner surface of the shell and the other end face of the planar friction plate, at least one piezoelectric ceramic driver arranged in the driver sleeve, the piezoelectric ceramic driver being in the shape of a cylinder, the axial direction of the piezoelectric ceramic driver being perpendicular to the inner wall of the bottom of the shell, the piezoelectric ceramic driver being provided with a sliding mechanism at the top end, the sliding mechanism being in slidable contact with the inner wall of the cover plate, and a connecting rod fixedly arranged on the outer surface of the shell and used for connecting with an external structure.

[0004] With the above specific structure, the piezoelectric ceramic driver can change the axial length by applying electric current, change the pressure on the sliding mechanism and the planar friction plate, and simultaneously affect the friction force between the planar friction plate and the inner wall of the bottom of the shell, so as to finally achieve the effect of adjusting damping. The variable damping can meet the complex shock-absorbing requirements, such as dealing with small deformation and other irregular deformations.

[0005] As a possible implementation, the energy recovery mechanism comprises: at least two permanent magnets symmetrically arranged on the inner wall of the cover plate and the bottom of the shell; and at least one magnetic induction coil sleeved on the planar friction plate and connected with an external energy storage circuit.

[0006] With the above possible implementation, the two permanent magnets generate a certain size of magnetic field in the shell, and when the magnetic induction coil moves with the planar friction plate, the magnetic induction coil cuts the magnetic induction lines to generate electricity.

[0007] As a possible implementation, the energy recovery mechanism comprises: at least two permanent magnets symmetrically arranged on the inner wall of the cover plate and the bottom of the shell; and at least one magnetic induction coil sleeved on the planar friction plate and connected with an external energy storage circuit.

[0008] With the above possible implementation, the two permanent magnets generate a certain size of magnetic field in the shell, and when the magnetic induction coil moves with the planar friction plate, the magnetic induction coil cuts the magnetic induction lines to generate electricity.

[0009] As a possible implementation, the displacement amplification mechanism comprises: a pull ring hingedly connected to the end of the actuator rod; and an amplification lever arranged on the pull ring and provided with a fixed hinge.

[0010] With the above possible implementation, when the external force causes small deformation of the structure, the displacement amplification mechanism amplifies and transmits the displacement to the actuator rod.

[0011] As a possible implementation, the sliding mechanism comprises: a clamping terminal fixedly arranged at the top end of the piezoelectric ceramic driver; a first friction plate arranged between the clamping terminal and the cover plate, the first friction plate being fixedly connected with the clamping terminal and being in slidable contact with the inner wall of the cover plate.

[0012] As a possible implementation, the inner surface of the cover plate is provided with at least one concave arc surface, and the upper surface of the first friction plate is a convex arc surface, the convex arc surface and the concave arc surface being matched to generate radial pressure of the first friction plate during sliding to enhance the friction.

[0013] With the above possible implementation, the first friction plate generates radial pressure during sliding to enhance the friction, and the variable damping effect can be further achieved.

[0014] As one possible implementation, the first reset device is a first reset spring, with its two ends fixed to one end face of the limiting plate and the flat friction plate, respectively; the second reset device is a second reset spring, with its two ends fixed to one inner surface of the housing and the other end face of the flat friction plate, respectively.

[0015] As one possible implementation, a limit bolt is provided on the actuator rod to limit the maximum stroke of the actuator rod.

[0016] As one possible implementation, a voltage sensor is provided on the piezoelectric ceramic actuator.

[0017] As one possible implementation, the cover plate is fixedly connected to the housing by at least one preload bolt. Attached Figure Description

[0018] The various technical features of this application and their relationships will be further explained below with reference to the accompanying drawings. The drawings are exemplary; some technical features are not shown to scale, and some drawings may omit technical features commonly used in the art to which this application pertains that are not essential for understanding and implementing this application, or additionally show technical features that are not essential for understanding and implementing this application. In other words, the combination of various technical features shown in the drawings is not intended to limit this application. Furthermore, throughout this application, the same reference numerals refer to the same things. Specific descriptions of the drawings are as follows:

[0019] Figure 1 This is a cross-sectional view of the friction damper involved in the embodiments of this application;

[0020] Figure 2 This is a schematic diagram of the coaxial coil of the friction damper involved in the embodiments of this application;

[0021] Figure 3 This is a schematic diagram of the displacement amplification mechanism in the friction damper according to an embodiment of this application.

[0022] Explanation of reference numerals in the attached drawings: 100-Housing; 200-Cover plate; 210-Preload bolt; 300-Flat friction plate; 310-Actuator sleeve; 320-Piezoelectric ceramic actuator; 321-Tightening terminal; 322-Magnetic coil; 330-First reset device; 340-Second reset device; 400-Limiting plate; 500-Limiting rod; 600-Actuating rod; 610-Limiting bolt; 620-Pull ring; 630-Hinge device; 700-First friction plate; 800-Connecting rod; 900-Coaxial coil; 1000-Amplifying lever; 1010-Fixed hinge; 1100-Permanent magnet. Detailed Implementation

[0023] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0024] This application provides a friction damper, which consists of a housing 100, a flat friction plate 300, a limiting plate 400, a reset device, a connecting rod 800, and at least one piezoelectric ceramic actuator 320.

[0025] Among them, such as Figure 1 As shown, the housing 100 is rectangular, and a cover plate 200 is fitted onto its upper end. The cover plate 200 is fixedly connected to the housing 100 by at least one pre-tightening bolt 210. The inner surface of the cover plate 200 is provided with at least one concave arc surface.

[0026] In this embodiment, the cover plate 200 is fixedly connected to the housing 100 by six preload bolts 210. Alternatively, in other embodiments, a different number of preload bolts 210 may be used, such as four, eight, etc.

[0027] The connecting rod 800 is fixedly mounted on the outer surface of the housing 100 for connection with the external structure.

[0028] Among them, such as Figure 1 As shown, a planar friction plate 300 is disposed within the housing 100. The planar friction plate 300 is in slidable contact with the bottom inner wall of the housing 100. An actuating rod 600 and a limiting rod 500 extend from both end faces of the planar friction plate 300 along the length of the housing 100, with the actuating rod 600 extending beyond the housing 100. At least one actuator sleeve 310 is provided on the planar friction plate 300, with the actuator sleeve 310 perpendicularly facing the cover plate 200. Figure 3 As shown, a displacement amplification mechanism is provided at the end of the actuating rod 600. The displacement amplification mechanism includes a pull ring 620 and an amplifying lever 1000. The pull ring 620 is hinged to the end of the actuating rod 600. The amplifying lever 1000 is mounted on the pull ring 620, and a fixed hinge 1010 is provided on the amplifying lever 1000. The fixed hinge 1010 is used for fixed connection to an external structure. When a small deformation or displacement occurs, the displacement amplification mechanism amplifies the displacement and transmits it to the actuating rod 600 through the lever principle, thereby improving the shock absorption effect.

[0029] In this embodiment, as Figure 1 As shown, a limit bolt 610 is provided on the actuator 600 to limit the maximum stroke of the actuator 600. Alternatively, in other embodiments, other types of limiting devices may be used, such as limit springs.

[0030] In this embodiment, the actuating rod 600 is also provided with a hinge device 630, which allows the actuating rod 600 to fold according to the hinge device 630. In other embodiments, other types of bending mechanisms can also be used, such as multi-link bending mechanisms and hydraulic bending mechanisms.

[0031] Among them, such as Figure 1 As shown, the limiting plate 400 is disposed on the bottom inner wall of the housing 100 and is vertically upward. The limiting rod 500 passes through the limiting plate 400. By setting the limiting plate 400, it is possible to prevent the planar friction plate 300 from sliding excessively within the housing 100 when subjected to external forces exceeding the design range, thereby preventing damage to the friction damper provided in this embodiment.

[0032] Among them, such as Figure 1 As shown, the reset device includes a first reset device 330 and a second reset device 340. The first reset device 330 is sleeved on the limiting rod 500, with its two ends abutting against one end face of the limiting plate 400 and the flat friction plate 300, respectively. The second reset device 340 is sleeved on the actuating rod 600, with its two ends abutting against one inner surface of the housing 100 and the other end face of the flat friction plate 300, respectively.

[0033] In this embodiment, the first reset device 330 is a first reset spring, with its two ends fixed to one end face of the limiting plate 400 and the flat friction plate 300, respectively; the second reset device 340 is a second reset spring, with its two ends fixed to one inner surface of the housing 100 and the other end face of the flat friction plate 300, respectively. The first reset spring is a compression spring, and the second reset spring is a tension spring. Alternatively, in other embodiments, other types of reset devices may be used, such as hydraulic devices.

[0034] Among them, such as Figure 1 As shown, at least one piezoelectric ceramic actuator 320 is disposed in the actuator sleeve 310, and the piezoelectric ceramic actuator 320 is cylindrical. The axial direction of the piezoelectric ceramic actuator 320 is perpendicular to the bottom inner wall of the housing 100. A sliding mechanism is provided at the top of the piezoelectric ceramic actuator 320. The sliding mechanism is in slidable contact with the inner wall of the cover plate 200.

[0035] In this embodiment, a voltage sensor is provided on the piezoelectric ceramic actuator 320. Piezoelectric ceramics exhibit the piezoelectric effect, meaning that when an electric field is applied to a piezoelectric ceramic, mechanical deformation occurs; conversely, when pressure is applied, an electric field is generated. For example, commonly used lead zirconate titanate piezoelectric ceramics (PZT) exhibit the piezoelectric effect. Under the influence of an electric field, the electric dipoles inside the ceramic undergo orientation changes, resulting in changes in size.

[0036] In this embodiment, as Figure 1 As shown, the planar friction plate 300 is provided with two actuator sleeves 310, and each sleeve contains a piezoelectric ceramic actuator 320. In other embodiments, different numbers of actuator sleeves 310 can be provided, such as three or four.

[0037] Among them, such as Figure 1 As shown, the friction damper involved in this application embodiment also includes an energy recovery mechanism. The energy recovery mechanism includes two permanent magnets 1100 and at least one magnetic induction coil 322. Taking the two permanent magnets 1100 as an example, they are symmetrically arranged on the cover plate 200 and the inner wall of the bottom of the housing 100. At least one magnetic induction coil 322 is sleeved on the planar friction plate 300 and connected to an external energy storage circuit. The permanent magnets 1100 generate a magnetic field of a certain magnitude within the housing 100. When the planar friction plate 300 is slid under external force, the magnetic induction coil 322 sleeved on it cuts the magnetic field, thereby generating an induced current on it. The induced current on the magnetic induction coil 322 is collected into the external energy storage circuit, thereby realizing energy recovery.

[0038] Among them, such as Figure 2 As shown, the friction damper in this embodiment further includes a pair of coaxial coils 900. The coaxial coils 900 are respectively disposed on the inner wall of the cover plate 200 and the bottom inner wall of the housing 100, and are electrically connected to an external power source. By energizing the coaxial coils 900 and designing a suitable coil spacing D and coil radius R, a uniform magnetic field region with good linearity between its intensity and the coil current can be generated at the midpoint of the common axis. Specifically, in this embodiment, the coil spacing D and the coil radius R are equal.

[0039] According to Faraday's law of electromagnetic induction, when a conductor cuts magnetic field lines, an induced electromotive force is generated inside, forming eddy currents. Lenz's law states that the direction of these eddy currents always opposes the conductor's motion, causing kinetic energy to be converted into Joule heat, which manifests as damping in this embodiment. In this embodiment, the planar friction plate 300 is made of a conductor. When the planar friction plate 300 slides and cuts magnetic field lines in a uniform magnetic field, it is damped by eddy currents. When the friction damper experiences a large displacement, the current can be adjusted to regulate the strength of the magnetic field, resulting in greater damping.

[0040] Among them, such as Figure 1As shown, the sliding mechanism includes a clamping terminal 321 and a first friction plate 700. The clamping terminal 321 is fixedly disposed at the top of the piezoelectric ceramic actuator 320. The first friction plate 700 is disposed between the clamping terminal 321 and the cover plate 200, and the first friction plate 700 is fixedly connected to the clamping terminal 321. The first friction plate 700 is in slidable contact with the inner wall of the cover plate 200. The upper surface of the first friction plate 700 is a convex arc surface. The convex arc surface cooperates with the concave arc surface, so that the first friction plate 700 generates radial pressure during sliding to enhance friction. In addition, in other embodiments, other structures can also be used. For example, the inner surface of the cover plate 200 is provided with at least one inclined surface, which extends towards the connecting rod 800 and slopes downward. At the same time, the upper surface of the first friction plate 700 is a corresponding reverse inclined surface.

[0041] In this embodiment, as Figure 1 As shown, the inner wall of the cover plate 200 has two concave arc surfaces, which respectively cooperate with the first friction plate 700 in the sliding mechanism above the two piezoelectric ceramic actuators 320. In other embodiments, the number of concave arc surfaces can be three, four, etc.

[0042] In other embodiments, other types of materials can be used to achieve variable damping. For example, shape memory alloys (e.g., nickel-titanium alloys, Ni-Ti alloys) can be used to fabricate the actuator, and combined with a heating device, to achieve adjustable damping. When the shape memory alloy is at a low temperature, it is in the martensitic phase, which is soft; when the shape memory alloy is at a high temperature, it is in the austenitic phase, which is hard. Therefore, at low temperatures, the shape memory alloy is softer, exerting less pressure on the planar friction plate 300 and the sliding mechanism, resulting in lower damping; at high temperatures, the shape memory alloy hardens, exerting greater pressure on the planar friction plate 300 and the sliding mechanism, resulting in greater damping. When increased damping is required, the shape memory alloy can be heated using a heating device. The heating device can be an electric heating device powered by an external power source. The heating device is directly mounted on the shape memory alloy for direct heating. Alternatively, it can be heated by ambient heat, i.e., directly heating the planar friction plate 300 or the housing 100.

[0043] Furthermore, in other embodiments, a magnetorheological fluid can be used, which is filled into the shell 100, and a magnetic field is applied to the magnetorheological fluid through a coaxial coil 900. A magnetorheological fluid is a smart material composed of magnetic particles (such as carbonyl iron powder), a carrier fluid (silicone oil, mineral oil, etc.), and additives (anti-settling agents, antioxidants). Its core characteristic is the magnetorheological effect: in the absence of a magnetic field, the magnetic particles are randomly distributed, and the fluid is a low-viscosity liquid that can flow freely; when a magnetic field is applied, the particles arrange themselves along the magnetic field lines into chain-like or columnar structures, forming a shear-resistant "solid network," and the viscosity increases sharply, exhibiting solid-like behavior. Simultaneously, the transition between these two states occurs in milliseconds. Moreover, the magnetic field can be switched an unlimited number of times to change the fluid state of the magnetorheological fluid. The rheological properties (viscosity) can be precisely controlled by adjusting the magnetic field strength. In this embodiment, the rheological properties of the magnetorheological fluid can be controlled by adjusting the current in the coaxial coil 900. When the planar friction plate 300 slides within the housing 100, it is subjected to adjustable resistance from the magnetorheological fluid, thereby achieving a variable damping effect.

[0044] In the embodiments provided in this application, the magnetorheological fluid, shape memory alloy actuator, and piezoelectric ceramic actuator 320 can be used individually, or the magnetorheological fluid can be used in conjunction with the shape memory alloy actuator or the piezoelectric ceramic actuator 320.

[0045] In summary, the friction damper of this application embodiment can achieve variable damping by applying variable resistance to the planar friction plate 300 using a controllable piezoelectric ceramic actuator 320, shape memory alloy, and / or magnetorheological fluid. Simultaneously, a magnetic field is created using a coaxial coil 900, which applies resistance to the planar friction plate 300 through eddy current effect, achieving variable damping. A cover plate 200 with a concave arc surface is also used to cooperate with the convex arc surface on the first friction plate 700, similarly achieving variable damping. Furthermore, a constant magnetic field is generated in the housing 100 of the friction damper of this application embodiment using a permanent magnet 1100. An induced current is generated by moving and cutting the magnetic field through the magnetic coil 322 on the planar friction plate 300, and energy recovery is achieved by collecting the induced current. The variable damping friction damper of this application embodiment can adapt to more vibration reduction scenarios. For example, in scenarios with small vibration displacement, the displacement can be amplified by a displacement amplification mechanism, thus avoiding the problem that the friction damper cannot function effectively due to excessively small displacement. For example, in scenarios with large vibration displacement, the displacement amplification mechanism can be removed, and the damping can be increased through the variable damping function, thereby improving the vibration reduction effect.

[0046] The term “comprising” as used throughout this application should not be construed as limited to what is listed thereafter; it does not exclude other structural elements or steps.

[0047] It is understood that those skilled in the art can combine the features mentioned in one or more embodiments throughout this application with features from other embodiments in any appropriate manner to implement this application.

[0048] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the technical concept of this application, all of which fall within the scope of protection of this application.

Claims

1. A friction damper, characterized by It comprises: a shell in the shape of a cuboid, a cover plate being fitted on the shell; a planar friction plate arranged in the shell, the planar friction plate being in slidable contact with the inner wall of the bottom of the shell, two side end faces of the planar friction plate extending in the length direction of the shell to form an actuating rod and a limiting rod, the actuating rod extending out of the shell, at least one driver sleeve being arranged on the planar friction plate, the driver sleeve being vertically directed towards the cover plate; a limiting plate arranged on the inner wall of the bottom of the shell and vertically arranged upwards, the limiting rod penetrating through the limiting plate; a reset device comprising a first reset device and a second reset device, the first reset device being sleeved on the limiting rod, two ends of the first reset device being respectively abutted against the limiting plate and one end face of the planar friction plate, the second reset device being sleeved on the actuating rod, two ends of the second reset device being respectively abutted against an inner surface of the shell and the other end face of the planar friction plate; at least one piezoelectric ceramic driver arranged in the driver sleeve, the piezoelectric ceramic driver being in the shape of a cylinder, the axial direction of the piezoelectric ceramic driver being perpendicular to the inner wall of the bottom of the shell, a sliding mechanism being arranged at the top end of the piezoelectric ceramic driver, the sliding mechanism being in slidable contact with the inner wall of the cover plate; a connecting rod fixedly arranged on the outer surface of the shell and used for connecting with an external structure.

2. The friction damper of claim 1, wherein, It further comprises an energy recovery mechanism, the energy recovery mechanism comprising: at least two permanent magnets symmetrically arranged on the cover plate and the inner wall of the bottom of the shell; at least one magnetic induction coil sleeved on the planar friction plate and connected with an external energy storage circuit.

3. The friction damper of claim 1, wherein, It further comprises a pair of coaxial coils, the two coils being respectively arranged on the inner wall of the cover plate and the inner wall of the bottom of the shell, the two coils being electrically connected with an external power supply.

4. The friction damper of claim 1, wherein, It further comprises a displacement amplification mechanism arranged at the end of the actuating rod, the displacement amplification mechanism comprising: a pull ring hinged at the end of the actuating rod; an amplification lever arranged on the pull ring, the amplification lever being provided with a fixed hinge.

5. The friction damper of claim 1, wherein, The sliding mechanism comprises: a top tightening terminal fixedly arranged at the top end of the piezoelectric ceramic driver; a first friction plate arranged between the top tightening terminal and the cover plate, the first friction plate being fixedly connected with the top tightening terminal, the first friction plate being in slidable contact with the inner wall of the cover plate.

6. The friction damper of claim 5, wherein, The inner surface of the cover plate is provided with at least one inner concave curved surface, the upper surface of the first friction plate being an outer convex curved surface, the outer convex curved surface being matched with the inner concave curved surface, so that the first friction plate generates radial pressure when sliding to enhance the friction force.

7. The friction damper according to claim 1, wherein the first reset device is a first reset spring, two ends of the first reset spring being respectively fixed on the limiting plate and one end face of the planar friction plate; the second reset device is a second reset spring, two ends of the second reset spring being respectively fixed on an inner surface of the shell and the other end face of the planar friction plate.

8. The friction damper of claim 1, wherein, a limiting bolt is arranged on the actuating rod and used for limiting the maximum stroke of the actuating rod.

9. The frictional damper according to claim 1, wherein, a voltage sensor is arranged on the piezoelectric ceramic driver.

10. The friction damper of claim 1, wherein, the cover plate is fixedly connected with the shell through at least one pre-tightening bolt.

Images