Acoustic black hole vibration and noise reduction structure

Abstract

The acoustic black hole vibration and noise reduction structure comprises a main body, and an acoustic black hole cavity is formed in the main body; in the axis direction of the cavity, the acoustic black hole cavity comprises a first cavity section, a second cavity section and a third cavity section, and the first cavity section and the third cavity section are both cylindrical; the diameter of the second cavity section is reduced in a power function mode from the end, connected with the first cavity section, of the second cavity section to the end, connected with the third cavity section, of the second cavity section. When the body receives external wave excitation, an acoustic black hole cavity within the body may capture waves, absorb vibrations and acoustic energy into the acoustic black hole cavity. The damping sound absorption block arranged in the acoustic black hole structure dissipates captured vibration and sound wave energy, the damping sound absorption coating on the outer surface of the main body absorbs the remaining part of vibration and sound energy, and efficient vibration and noise reduction at the connecting part can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of vibration noise control, and in particular to an acoustic black hole vibration reduction and noise reduction structure. Background Art

[0002] With the rapid development of industrialization and urbanization, noise pollution has become an increasingly serious environmental problem. In mechanical equipment, connection structures are used to connect different mechanical components or parts together. Common mechanical connection structures include threaded connections, pin, key and spline connections, rivet connections, etc. When the wave propagates, it will be transmitted from one connection to another through the connection structure, causing the mechanical system to generate excessive vibration noise. This will not only affect the performance and service life of the equipment, but may also cause interference to the surrounding environment and affect people's normal life and work.

[0003] Vibration and noise reduction technologies are mainly divided into two categories: active control and passive control. Active control is based on the principle of wave destructive interference. It captures vibration noise signals through sensors and uses actuators to emit an anti-phase wave with the same amplitude and opposite phase as the vibration noise signal. When the anti-phase wave meets the original wave, the two will cancel each other out, thereby achieving the effect of vibration and noise reduction. Active control technology has good low-frequency effects, but it will introduce electronic devices, making the system complex and costly, and may cause stability and reliability problems. Passive control mainly blocks, absorbs and consumes vibration noise energy through the physical effects of materials and structures themselves. It has the advantages of simple implementation, low cost, and no need for additional energy. It has significant advantages in the medium and high frequency bands, and is therefore widely used in many occasions.

[0004] As a new type of passive control vibration reduction and noise reduction technology, Acoustic Black Hole (ABH) has attracted widespread attention from scholars at home and abroad. The concept of ABH was first derived from the black hole phenomenon in astrophysics. In the field of vibration and acoustics, ABH refers to the design of structures or material parameters of specific shapes so that the speed of waves gradually slows down during propagation, and eventually gathers in a certain area and is effectively absorbed and dissipated. Existing connection technologies do not consider the solution of embedding vibration reduction and noise reduction structures and materials, and traditional vibration reduction and noise reduction technologies cannot adapt to the special needs of connection parts. Combining ABH technology and the form of connection structure, it is expected to achieve efficient vibration reduction and noise reduction at the connection parts. To this end, the present application proposes an acoustic black hole vibration reduction and noise reduction structure. Summary of the invention

[0005] In view of the vibration and noise problem of the connecting device in the prior art, the present invention proposes an acoustic black hole vibration reduction and noise reduction structure, and the specific technical solution is as follows: An acoustic black hole vibration reduction and noise reduction structure comprises a main body, in which an acoustic black hole cavity is arranged; along the axial direction of the cavity, the acoustic black hole cavity comprises a first cavity segment, a second cavity segment and a third cavity segment, and the first cavity segment and the third cavity segment are both cylindrical; from the connecting end of the second cavity segment and the first cavity segment to the connecting end of the second cavity segment and the third cavity segment, the diameter of the second cavity segment decreases like a power function.

[0006] Furthermore, the power exponent of the power function is greater than or equal to 2.

[0007] Furthermore, the diameter of the first cavity segment is greater than or equal to five times the diameter of the third cavity segment.

[0008] Furthermore, a damping sound-absorbing block is provided inside the acoustic black hole structure.

[0009] Furthermore, the material of the damping sound absorbing block is rubber, polyurethane or polymer resin.

[0010] Furthermore, a damping sound absorbing coating is provided on the outer surface of the main body.

[0011] Furthermore, the material of the damping sound absorbing coating is polyurethane, polymer resin, epoxy resin or polytetrafluoroethylene.

[0012] Furthermore, the main body is a bolt or a pin.

[0013] The beneficial effects of the present invention are: When the main body receives external wave excitation, the acoustic black hole cavity inside the main body can capture the wave and absorb the vibration and sound energy into the acoustic black hole cavity. The damping sound-absorbing block set inside the acoustic black hole structure dissipates the captured vibration and sound wave energy, and the damping sound-absorbing coating on the outer surface of the main body absorbs the remaining vibration and sound energy, which can achieve efficient vibration reduction and noise reduction at the connection part. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0015] Figure 1 is a schematic diagram of the acoustic black hole cavity of the present invention; Figure 2 This is an application diagram of the acoustic black hole vibration reduction and noise reduction structure in Example 1. Figure 1 ; Figure 3 This is an application diagram of the acoustic black hole vibration reduction and noise reduction structure in Example 1. Figure 2; Figure 4 It is the amplitude diagram of the traditional connection structure under the excitation of external simple harmonic load; Figure 5 It is an amplitude diagram of the acoustic black hole vibration reduction and noise reduction structure of the present invention under the excitation of an external simple harmonic load; Figure 6 It is a schematic diagram of the application of the acoustic black hole vibration reduction and noise reduction structure in the second embodiment.

[0016] In the figure: 1. main body; 2. first thin plate; 3. second thin plate; 4. nut; 5. damping sound absorbing block. DETAILED DESCRIPTION

[0017] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0018] The main body of the present invention can be a cylindrical connecting member such as a bolt or a pin. The present invention provides the following specific implementation schemes: Embodiment 1: First, take the main body as a bolt as an example. Figure 1-3 As shown, the present invention provides an acoustic black hole vibration reduction and noise reduction structure, comprising a main body 1, in which an acoustic black hole cavity is arranged; along the axial direction of the cavity, the function form of the acoustic black hole is a piecewise function form, and the acoustic black hole cavity comprises a first cavity segment l 1. Second cavity section l 2 and the third cavity segment l 3. First cavity section l 1 and the third cavity segment l 3 are cylindrical; from the second cavity section l 2 and the first cavity segment l 1 to the second cavity section l 2 and the third cavity segment l 3, the second cavity section l The diameter of 2 decreases in a power function. The power function is y=x m , where 0< x ≤ l 1, the thickness of the acoustic black hole structure is h 1; in l 1< x ≤ l 2, the thickness decreases in a power function according to the x coordinate; l 2< x ≤ l 3 places, thickness is h 2.

[0019] Preferably, the second cavity segment l 2 The power exponent of the power function of the diameter change is greater than or equal to 2, that is, m ≥ 2.

[0020] Preferably, the first cavity segment l The diameter of 1 is greater than or equal to the third cavity segment l 3Five times the diameter.

[0021] Preferably, the acoustic black hole structure is provided with a damping sound absorbing block 5, the material of which is rubber, polyurethane or polymer resin. The outer surface of the main body 1 is provided with a damping sound absorbing coating, the material of which is polyurethane, polymer resin, epoxy resin or polytetrafluoroethylene.

[0022] In addition, in this embodiment, the outer surface of the nut 4 that cooperates with the main body 1 is also provided with a damping sound absorbing coating.

[0023] Use the main body 1 to connect two connecting parts (taking thin plates as an example). When there is vibration excitation and acoustic excitation in the outside world, the wave will be transmitted from the first thin plate 2 to the second thin plate 3 (and vice versa), causing the second thin plate 3 to generate vibration and noise, and then transmitted to other parts connected to the second thin plate 3. The connection part is one of the key ways for vibration and sound waves to transmit energy. The main body 1 will assume the function of fastening the connection and is also the part that the wave must pass through. Ideally, the acoustic black hole cavity inside the main body 1 can attract vibration and sound wave energy like a "black hole" and dissipate it through the internal damping material to form a "vibration and sound energy absorption trap". In this way, the vibration and sound energy of the first thin plate 2 will no longer be transmitted to the second thin plate 3. Of course, due to the existence of the cut-off thickness, part of the vibration and sound wave energy cannot be absorbed, and these vibration and sound wave energies can be consumed by the wall collision and friction of the damping sound absorbing coating coated on the surface of the main body 1 and the nut 4.

[0024] Figure 4-5 The figure shows the simulation analysis results of the conventional connection structure and the vibration and noise reduction structure of the present invention under the same external excitation conditions. Figure 4 and Figure 5It can be seen from the results that the vibration reduction and noise reduction structure of the present invention can effectively absorb the energy of vibration and sound waves in a wide frequency range.

[0025] Embodiment 2: In the second aspect, taking the main body as the pin as an example, Figure 6 As shown, the main body 1 connects two thin plates. When there is vibration excitation and sound excitation in the outside world, the vibration and sound wave energy are attracted by the acoustic black hole cavity inside the main body 1 and dissipated by the internal damping material. The part of the vibration and sound wave energy that cannot be absorbed can be consumed by collision and friction with the wall of the damping and sound-absorbing coating on the surface of the main body 1.

[0026] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. An acoustic black hole vibration reduction and noise reduction structure, characterized in that: The invention comprises a main body, in which an acoustic black hole cavity is arranged; along the axial direction of the cavity, the acoustic black hole cavity comprises a first cavity segment, a second cavity segment and a third cavity segment, and the first cavity segment and the third cavity segment are both cylindrical; from the connecting end of the second cavity segment and the first cavity segment to the connecting end of the second cavity segment and the third cavity segment, the diameter of the second cavity segment decreases like a power function.

2. The acoustic black hole vibration reduction and noise reduction structure according to claim 1, characterized in that: The power exponent of a power function is greater than or equal to 2.

3. The acoustic black hole vibration reduction and noise reduction structure according to claim 1, characterized in that: The diameter of the first cavity segment is greater than or equal to five times the diameter of the third cavity segment.

4. The acoustic black hole vibration reduction and noise reduction structure according to claim 1, characterized in that: A damping sound-absorbing block is arranged inside the acoustic black hole structure.

5. The acoustic black hole vibration reduction and noise reduction structure according to claim 4, characterized in that: The material of the damping sound absorbing block is rubber, polyurethane or high molecular resin.

6. The acoustic black hole vibration reduction and noise reduction structure according to claim 1, characterized in that: The outer surface of the main body is provided with a damping sound absorbing coating.

7. The acoustic black hole vibration reduction and noise reduction structure according to claim 6, characterized in that: The material of the damping sound absorbing coating is polyurethane, polymer resin, epoxy resin or polytetrafluoroethylene.

8. An acoustic black hole vibration reduction and noise reduction structure according to any one of claims 1 to 7, characterized in that: The body is a bolt or a pin.

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