Cylindrical and conical combined acoustic black hole muffler structure and super-silent cabinet

Abstract

The application relates to a cylindrical and conical combined acoustic black hole silencing structure and a super-silence type cabinet, and the silencing structure is characterized in that a cylindrical outer polyurethane layer and a cylindrical inner polyurethane layer are respectively adhered to the outer surface and the inner wall surface of a cylindrical sleeve, a silencing small hole near the bottom end of the cylindrical sleeve, a silencing small hole near the bottom end of the cylindrical outer polyurethane layer and a silencing small hole near the bottom end of the cylindrical inner polyurethane layer are all in one-to-one correspondence from the inside to the outside, and the three form a cylindrical part; a conical outer polyurethane layer and a conical inner polyurethane layer are respectively adhered to the outer surface and the inner wall surface of a conical sleeve; the three form a conical part; the inner hole of the conical part gradually decreases from the bottom end to the top end; the conical part is integrally inserted into the cylindrical part from the top end to the bottom end; a special-shaped sound wave reflection member is fixedly connected to the center hole part of the cylindrical sleeve, the sharp top of the special-shaped sound wave reflection member extends to the top surface of the conical part, and the sound wave reflection area is formed between the cylindrical inner polyurethane layer and the conical outer polyurethane layer. The application achieves a better sound absorption and noise reduction effect.

Description

Technical Field

[0001] This invention belongs to the field of equipment noise reduction design, and in particular relates to an acoustic black hole silencing structure combining cylindrical and conical surfaces and an ultra-quiet cabinet. Background Technology

[0002] Military electronic cabinets are integrated computing system devices commonly used in personnel living environments. They typically contain 6-7 air-cooled, ruggedized chassis. When the cooling fans are operating, the noise level can reach as high as 64 dB due to noise amplification. In personnel living quarters, this noise level can severely disrupt their daily routines. Currently, noise reduction measures for military electronic cabinets mainly include attaching sound-absorbing materials to the inner walls of the cabinet, reducing fan speed, and using liquid cooling. While these three measures can reduce noise levels to some extent, they all have significant drawbacks: sound-absorbing materials have low low-frequency absorption coefficients and require a certain thickness to achieve their intended effect; reducing fan speed significantly reduces noise but also greatly weakens heat dissipation performance; liquid-cooled cabinets can control noise below 40 dB, but their cost is 3-4 times higher than ordinary cabinets, and they require a dedicated liquid cooling source.

[0003] The concept of black holes originates from astronomy. In the field of vibration, a black hole vibration-absorbing structure refers to a structure where, when the thickness of a plate decreases according to a certain standard, vibration waves propagate within the plate with varying thickness. During this propagation, bending waves do not undergo reflection, hence the term "black hole vibration absorption." Addressing the noise reduction requirements of military electronic cabinets in personnel living quarters, this invention pre-designs an acoustic black hole silencing device based on the black hole absorption principle and an ultra-quiet cabinet employing this silencing device. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an acoustic black hole anechoic structure combining cylindrical and conical surfaces and an ultra-quiet cabinet.

[0005] One of the above-mentioned objectives of the present invention is achieved through the following technical solution:

[0006] An acoustic black hole silencing structure combining cylindrical and conical surfaces includes an outer polyurethane layer on the cylindrical surface, a cylindrical sleeve, an inner polyurethane layer on the cylindrical surface, an outer polyurethane layer on the conical surface, a conical sleeve, an inner polyurethane layer on the conical surface, and an irregularly shaped acoustic wave reflector.

[0007] The bottom end of the column sleeve is an open end with a flange edge, and the top end of the column sleeve has a central hole. The outer polyurethane layer and the inner polyurethane layer of the column surface are respectively bonded and fixed to the outer surface and the inner wall surface of the column sleeve. Sound-absorbing holes are evenly distributed near the bottom end of the column sleeve, near the bottom end of the outer polyurethane layer, and near the bottom end of the inner polyurethane layer. The sound-absorbing holes of the three are aligned one-to-one. The column sleeve, the outer polyurethane layer, and the inner polyurethane layer constitute the column surface component.

[0008] The bottom end of the tapered sleeve is provided with a flange edge. The outer polyurethane layer and the inner polyurethane layer of the tapered surface are respectively bonded and fixed to the outer surface and inner wall surface of the tapered sleeve. The tapered sleeve, the outer polyurethane layer, and the inner polyurethane layer constitute a tapered component. The inner hole of the tapered component gradually decreases from the bottom end to the top end. The radius of the inner hole of the inner polyurethane layer of the tapered surface is approximately equal to the radius of the inner hole from the top end to the bottom end. The value changes in mm, where x is the distance from the top of the cone.

[0009] The conical component is integrally inserted into the cylindrical component from top to bottom, and is fixedly connected by bolts to the flange edges of the cylindrical sleeve and the conical sleeve. The irregularly shaped acoustic wave reflector is an arc-shaped conical sleeve structure with a pointed top and a longitudinal section surrounded by symmetrical arcs. The irregularly shaped acoustic wave reflector is located between the outer side of the top of the conical component and the inner side of the top of the cylindrical sleeve. The large end of the irregularly shaped acoustic wave reflector is fixedly connected to the central hole on the cylindrical sleeve by screws. The pointed top of the irregularly shaped acoustic wave reflector extends to the top surface of the conical component, so that the sound waves are reflected between the polyurethane layer inside the cylindrical surface and the polyurethane layer outside the conical surface, forming a sound energy concentration zone. In this space, the sound absorption performance of the sound-absorbing material is improved.

[0010] The second objective of this invention is achieved through the following technical solution:

[0011] An ultra-quiet server rack is disclosed, wherein the rear cover of the rack adopts an acoustic black hole silencing array structure combining cylindrical and conical surfaces. The array structure consists of a rear mounting plate, multiple sets of acoustic black hole silencing structures combining cylindrical and conical surfaces, a porous sound insulation cover, and a sound-absorbing cotton layer. Multiple mounting holes are evenly distributed along the horizontal and vertical directions on the rear mounting plate. The bottom ends of the multiple sets of acoustic black hole silencing structures combining cylindrical and conical surfaces are vertically and fixedly connected to the positions of the mounting holes. The porous sound insulation cover is a shell structure with an open front end, a flange edge, and evenly distributed small holes on the rear bottom. The porous sound insulation cover is fitted over the exterior of the multiple sets of acoustic black hole silencing structures combining cylindrical and conical surfaces, and its front flange edge is fixed to the rear side of the rack via screws. The sound-absorbing cotton layer is adhesively fixed to the front side of the rear mounting plate and has openings corresponding to the mounting holes on the rear mounting plate.

[0012] The advantages and positive effects of this invention are as follows:

[0013] 1. This invention uses a cylindrical-conical method, where sound waves are transmitted from the bottom of the conical surface to the bottom of the cylindrical surface, achieving sound wave reflection and transmission. By using half the length, double the transmission path is achieved, effectively saving space.

[0014] 2. The bottom of the cylindrical surface of the present invention is a sound energy concentration area. The cylindrical surface at this point has sound-absorbing holes and is covered with sound-absorbing material, which enhances the loss of sound energy.

[0015] 3. This invention combines multiple black hole noise reduction structures into a sound-absorbing array, which effectively improves noise reduction efficiency; the sound-absorbing array is directly opposite the noise source, which effectively reduces the distance between the noise source and the noise-absorbing black hole.

[0016] 4. The porous sound insulation cover structure outside the sound-absorbing array of this invention improves the noise reduction effect of the sound-absorbing material outside the cylindrical structure.

[0017] 5. This invention uses a cylindrical cone black hole silencing array structure to replace the traditional back cover plate, and uses black hole silencing to replace the traditional sound-absorbing cotton noise reduction method. The A-weighted sound pressure level is reduced by 15dB, and the cabinet noise is controlled within 50dB, solving the problem of excessive noise in electronic cabinets.

[0018] 6. Electronic cabinets using this design method replace the back cover of traditional cabinets with a black hole silencing array, while other parts remain the same. Therefore, this design method is highly adaptable and can be applied to the ultra-quiet design of standard electronic cabinets and the silent upgrade of traditional military electronic cabinets.

[0019] In summary, this invention employs a combination of cylindrical and conical surfaces to achieve sound wave reflection and transmission. It achieves the longest transmission path with the shortest possible black hole silencing structure length. Furthermore, during the black hole silencing process, by varying the radius of the inner wall of the conical surface, the reflection of sound waves towards the bottom of the conical surface is significantly reduced, resulting in the concentration of sound energy. In the sound energy concentration area, the noise reduction effect of the sound-absorbing material is enhanced. The black hole silencing structure of this invention is simple in structure, lightweight, can absorb low-frequency noise, has no impact on the heat dissipation performance of the cabinet, and has low production costs, making it suitable for noise reduction in military electronic cabinets. Attached Figure Description

[0020] Figure 1a This is a longitudinal sectional view of the acoustic black hole anechoic structure combining cylindrical and conical surfaces of the present invention;

[0021] Figure 1b This is a front view of the acoustic black hole anechoic structure combining cylindrical and conical surfaces of the present invention.

[0022] Figure 2 This is a three-dimensional exploded view of the acoustic black hole silencing structure combining cylindrical and conical surfaces of the present invention.

[0023] Figure 3a This is a front view of the acoustic black hole anechoic array structure combining cylindrical and conical surfaces of the present invention;

[0024] Figure 3b This is a longitudinal cross-sectional view of the acoustic black hole anechoic array structure combining cylindrical and conical surfaces of the present invention;

[0025] Figure 3c This is a rear view of the acoustic black hole anechoic array structure combining cylindrical and conical surfaces of the present invention;

[0026] Figure 4 This is a three-dimensional exploded view of the acoustic black hole noise reduction array structure combining cylindrical and conical surfaces of the present invention.

[0027] Figure 5a This is a structural view 1 of the ultra-quiet cabinet of the present invention;

[0028] Figure 5b This is a structural view of the ultra-quiet cabinet of the present invention. Figure 2 ;

[0029] Figure 6 This is a schematic diagram of the noise measurement points of the present invention;

[0030] Figure 7 This is a diagram showing the noise reduction effect (1 / 4 octave band) at the front end of the cabinet according to the present invention;

[0031] Figure 8 This is a diagram showing the noise reduction effect (1 / 4 octave band) at the back end of the cabinet according to the present invention. Detailed Implementation

[0032] The structure of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that these embodiments are descriptive and not limiting.

[0033] Based on the principle of black hole sound absorption, this invention proposes a black hole sound absorption structure that combines cylindrical and conical surfaces. This structure causes the cross-sectional radius of the noise transmission path to gradually decrease according to a certain rule, concentrating the sound energy in a local area between the cylindrical and conical surfaces. Sound energy is dissipated by using sound-absorbing materials and small-hole sound absorption and noise reduction methods, thus achieving the effect of black hole noise reduction.

[0034] Acoustic black hole anechoic structure combining cylindrical and conical surfaces, such as Figure 1a and 1b As shown, it consists of an outer polyurethane layer 1 on the cylindrical surface, an outer polyurethane layer 2 on the conical surface, a column sleeve 3, an inner polyurethane layer 4 on the cylindrical surface, an irregularly shaped acoustic wave reflector 5, an inner polyurethane layer 6 on the conical surface, and a conical sleeve 7. An exploded view is shown below. Figure 2 As shown. The installation of the cylindrical and conical acoustic black hole anechoic structure mainly involves four steps: First, 3M adhesive is used to attach the inner polyurethane layer 4 and the outer polyurethane layer 1 of the cylindrical surface to the inner and outer surfaces of the cylindrical sleeve 3, respectively. During bonding, it is ensured that the anechoic holes on the cylindrical sleeve are aligned with the anechoic holes on the inner and outer polyurethane layers of the cylindrical surface. Second, 3M adhesive is used to attach the inner polyurethane layer 6 and the outer polyurethane layer 2 of the conical surface to the outer surface of the conical structure. Next, fastening screws are used to install the irregularly shaped acoustic wave reflector 5 at the center hole at the top of the cylindrical sleeve. Finally, the cylindrical and conical components are combined to form... Figure 1a The acoustic black hole silencing structure shown.

[0035] When a sound wave is incident from the bottom end of the cone sleeve (the large-diameter section of the cone sleeve), the radius of the sound wave transmission path formed by the polyurethane layer inside the cone sleeve decreases in a predetermined manner. Specifically, from the small end (top) to the large end (bottom) of the polyurethane layer inside the cone sleeve, the radius decreases in a predetermined manner. Due to the variation in mm, the sound wave will directly incident on the top of the cone surface inside the polyurethane layer of the cone sleeve, without any outward reflection. During the transmission process, the polyurethane layer inside the cone surface will also absorb some sound energy. The irregularly shaped sound wave reflector will reflect the incident sound wave to the space between the polyurethane layer outside the cone surface and the polyurethane layer inside the cylinder surface. According to the black hole silencing principle, the sound energy is more concentrated when it is transmitted to the bottom of the cylinder sleeve. The bottom of the cylinder sleeve has sound-absorbing holes and is covered with inner and outer polyurethane sound-absorbing material layers. These sound-absorbing components will consume the concentrated sound energy, ultimately achieving the purpose of sound absorption and noise reduction. Some sound energy is also transmitted to the outside through the sound-absorbing holes at the bottom of the cylindrical cone sleeve.

[0036] The acoustic black hole anechoic array structure combining cylindrical and conical surfaces, such as Figure 3a , 3b As shown in 3c, the acoustic black hole sound-absorbing structure 11, consisting of a porous sound insulation cover 8, a rear mounting plate 9, a sound-absorbing cotton layer 10, and multiple sets of cylindrical and conical surfaces, is shown in the exploded view as follows. Figure 4 As shown.

[0037] The installation of the cylindrical-conical acoustic black hole anechoic array structure 12 mainly involves three steps: First, multiple sets of cylindrical-conical acoustic black hole anechoic structures are evenly distributed in both directions and screwed onto the rear mounting plate of the cabinet; second, sound-absorbing cotton is pasted on the empty area of ​​the rear mounting plate of the cabinet; and finally, a perforated soundproof cover is installed on the outermost side.

[0038] When the cabinet is in operation, the sound-absorbing cotton layer can dissipate the sound energy that does not enter the cylindrical-conical acoustic black hole anechoic structure. The sound energy that does enter the cylindrical-conical acoustic black hole anechoic structure is absorbed internally, and the remaining part passes through the anechoic holes, forming reverberation inside the porous soundproof enclosure. At this time, the polyurethane layer on the outside of the cylinder will absorb the remaining sound energy. After multi-stage anechoic treatment, the noise transmitted from the cabinet will be significantly reduced.

[0039] The main noise source of the server rack is the axial fan at the rear of the internal enclosure, located opposite the rear cover. When the fan rotates, the rear cover directly reflects the fan noise, causing the noise to be directly transmitted from the cooling duct to the outside of the rack. This invention applies an acoustic black hole silencing structure combining cylindrical and conical surfaces, arranged in an array to form a black hole silencing array. This replaces the traditional rear cover of the server rack, bringing the black hole silencing structure closer to the sound source. Therefore, the black hole array structure can directly absorb the noise from the cooling fan, improving silencing efficiency. Furthermore, there is no external reflection of sound waves, significantly improving the sound absorption coefficient inside the rack. Numerical calculations show that the electronic rack designed using this method reduces the A-weighted sound pressure level by 15 dB, controlling the rack noise below 50 dB, successfully solving the noise problem. Ultra-quiet electronic racks are available. Figure 5a and 5b As shown, the silent cabinet in this patent only replaces the back cover of the traditional cabinet with a black hole silencing array; the rest of the structure is the same as the traditional cabinet. It is suitable for the silent design of military electronic cabinets with high noise requirements, and the silent upgrade and transformation of traditional cabinets.

[0040] The ultra-quiet cabinet of this invention, as calculated numerically, has the following properties: Figure 6 As shown, at positions 1m from the front and rear of the cabinet, the sound pressure levels at 1 / 4 octave bands are respectively as follows: Figure 7 and Figure 8 As shown, the noise level of the cabinet is controlled to below 50dB, which is an improvement of about 12dB compared to traditional cabinets. The silent cabinet using this design method has a simple acoustic black hole silencing array structure, is easy to install, and its other structures are no different from those of traditional cabinets. It can be applied to noise reduction design of electronic cabinets with quiet requirements, and to the silent upgrade and transformation of traditional military electronic cabinets.

[0041] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A cylindrical-conical combined acoustic black hole sound attenuation structure, characterized in that; The sound wave reflection member is an arc-shaped cone sleeve structure with a pointed top and a symmetric circular arc line surrounding the longitudinal section. The bottom end of the sleeve is an open end and is provided with a flange edge, and the top end of the sleeve is provided with a central hole; the outer surface of the sleeve and the inner wall surface of the sleeve are respectively bonded and fixed with the outer polyurethane layer and the inner polyurethane layer, and the outer polyurethane layer and the inner polyurethane layer are uniformly provided with sound absorbing holes at positions close to the bottom end of the sleeve, the outer polyurethane layer and the inner polyurethane layer, and the sound absorbing holes of the three are in one-to-one correspondence; the sleeve, the outer polyurethane layer and the inner polyurethane layer constitute a cylindrical part. The bottom end of the taper sleeve is provided with a flange edge, and the outer polyurethane layer and the inner polyurethane layer are respectively bonded and fixed to the outer surface and the inner wall surface of the taper sleeve; the taper sleeve, the outer polyurethane layer and the inner polyurethane layer constitute a taper surface component; the inner hole of the taper surface component gradually decreases from the bottom end to the top end; the radius of the inner hole of the inner polyurethane layer gradually changes from the top end to the bottom end, wherein x is the distance from the top end of the taper surface. mm, wherein x is the distance from the top end of the taper surface. The cone part is integrally inserted into the cylindrical part from the top end to the bottom end, and is fixedly connected by bolts connected to the flange edges of the sleeve and the cone sleeve; the sound wave reflection member is an arc-shaped cone sleeve structure with a pointed top and a symmetric circular arc line surrounding the longitudinal section, and is arranged between the top end outside of the cone part and the top end inside of the sleeve; the large end of the sound wave reflection member is fixedly connected to the central hole of the sleeve by a screw, and the pointed top of the sound wave reflection member extends to the top surface of the cone part, so that the sound wave is reflected between the inner polyurethane layer and the outer polyurethane layer of the cone part, forming a sound energy concentration area.

2. A super-silent cabinet, characterized by: The rear cover plate of the cabinet adopts a cylindrical and conical combined acoustic black hole sound absorbing array structure, and the array structure is composed of a cabinet rear mounting plate, a plurality of cylindrical and conical combined acoustic black hole sound absorbing structures, a multi-hole sound insulation cover and a sound absorbing cotton layer; a plurality of mounting holes are uniformly arranged on the cabinet rear mounting plate along the horizontal and vertical directions, and the bottom ends of the plurality of cylindrical and conical combined acoustic black hole sound absorbing structures are fixedly connected to the mounting holes in a one-to-one vertical manner; the multi-hole sound insulation cover is a cover structure with an open front end and a flange edge and a plurality of holes uniformly arranged on the rear bottom; the multi-hole sound insulation cover is buckled outside the plurality of cylindrical and conical combined acoustic black hole sound absorbing structures, and the flange edge at the front end is fixedly installed on the rear side of the cabinet through screws; the sound absorbing cotton layer is bonded and fixed to the front side of the cabinet rear mounting plate and is provided with an opening at a position corresponding to the mounting hole of the cabinet rear mounting plate.

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