Subway carriage noise reduction cover and method based on sound energy conversion

Abstract

The invention relates to a metro carriage noise reduction cover and method based on sound energy conversion. The metro carriage noise reduction cover comprises a noise reduction cover body and a Holmholtz generator. The noise reduction cover body covers a metro seat, the opening end of the noise reduction cover body is fixed to the side wall of a metro, the noise reduction cover body is of a double-layer structure and comprises an outer layer shell and an inner layer shell, and an auxiliary noise reduction cavity is formed between the outer layer shell and the inner layer shell; the noise reduction cover body is provided with an auxiliary noise reduction cavity, the Helmholtz generator is installed in the auxiliary noise reduction cavity, the noise reduction cover body is provided with a sound collection hole and an air hole, and the Helmholtz generator is located in the sound collection hole. Compared with the prior art, the noise reduction device has the advantages of good noise reduction effect, simple structure, low cost and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of subways, and in particular to a subway car noise reduction cover based on sound energy conversion and a method thereof. Background Art

[0002] Noise causes systemic damage to the human body. Prolonged exposure to noise levels of 85 decibels or above can affect hearing, while long-term exposure to noise levels of 130 decibels or above can cause deafness. The harm caused by noise is even more severe for special populations, especially the elderly, pregnant women, and those with anxiety disorders, autism, and other conditions. First, in noisy environments, the elderly's ability to perceive high frequencies decreases significantly due to the gradual stiffening of their cochlea, making it difficult for passengers to distinguish speech and causing communication barriers. Long-term exposure to noise in pregnant women can easily lead to abnormal fetal development and even increase the risk of pregnancy complications. Furthermore, for those with psychological disorders such as anxiety and autism, being in a noisy environment can cause discomfort and worsen their condition.

[0003] The subway has become a means of transportation for most people due to its efficient transportation capacity and convenient coverage. However, studies have shown that the subway generates about 80 decibels of noise during operation. In particular, when the subway passes through curves, enters or leaves platforms, or enters or leaves tunnels, the noise generated due to acceleration or braking will be much greater than 80 decibels. When the subway passes through these sections, passengers will feel obvious discomfort, and special groups will be more seriously affected.

[0004] At present, domestic and foreign research on urban rail transit noise reduction mainly tends to study the noise source of rail vehicles and the noise propagation process. In order to reduce the impact of noise on subway passengers, in recent years, noise reduction sheets have been installed on train wheels, or the airtightness of the subway has been improved, the sound insulation and noise reduction capabilities have been strengthened, and the riding comfort of passengers has been improved.

[0005] However, the above-mentioned noise reduction method has the problem that the noise reduction effect cannot be guaranteed, and the method of reducing the noise of the train by improving the airtightness is obviously costly, especially the connection between the train sections, where the sealing is obviously not taken into account, resulting in poor noise reduction effect of the train and high noise reduction cost. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art methods of improving the sealing of trains or installing noise reduction sheets on wheels, which have poor noise reduction effect and high cost, and to provide a subway car noise reduction cover and method based on sound energy conversion.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] This solution provides a subway car noise reduction cover based on sound energy conversion, including a noise reduction cover body and a Holmz generator;

[0009] The noise reduction cover body is installed on the subway seat, and the open end of the noise reduction cover body is fixed to the side wall of the subway. The noise reduction cover body is a double-layer structure, including an outer shell and an inner shell, and an auxiliary noise reduction cavity is formed between the outer shell and the inner shell;

[0010] The Holmtz generator is installed in the auxiliary noise reduction cavity, the noise reduction cover body is provided with a sound collecting hole and a vent hole, and the Holmtz generator is located in the sound collecting hole.

[0011] Preferably, the noise reduction cover body is provided with an inlet and an outlet, and a closed door with a matching shape is provided in the inlet and the outlet, and the closed door is movably installed in the inlet and the outlet, and a sealing strip is provided between the closed door and the inlet and the outlet.

[0012] Preferably, the Holmtz generator comprises a Holmtz resonance cavity, a diaphragm, a magnet and a coil;

[0013] The Holmtz resonance cavity is a funnel-shaped structure, the inlet end of the Holmtz resonance cavity is opposite to the sound collecting hole, the diaphragm is installed at the outlet end of the Holmtz resonance cavity, the coil is wound on the magnetic steel, and the diaphragm covers the magnetic steel.

[0014] Preferably, the material of the noise reduction cover body is PC board.

[0015] Preferably, a sound insulation pad is provided inside the noise reduction cover body, and the sound insulation pad is set on the subway floor to absorb the noise generated by friction and vibration between the wheels and the rails.

[0016] Preferably, the sound insulation pad is made of polyurethane rubber or polyethylene.

[0017] Preferably, the Holmz generator is connected to a battery.

[0018] Preferably, a display screen and a speaker are provided inside the noise reduction cover body, the display screen and the speaker are mounted on the side wall of the subway, and the battery is electrically connected to the display screen and the speaker respectively.

[0019] Preferably, a ventilation fan is provided inside the noise reduction cover body, the ventilation fan is located in the vent hole, and the ventilation fan is electrically connected to the battery.

[0020] This solution also provides a noise reduction method for a subway car noise reduction cover based on sound energy conversion, comprising the following steps:

[0021] Determine local noise reduction areas on the subway based on the passenger density in each area of ​​the subway;

[0022] Installing noise reduction covers with Holmz generators on seats in localized noise reduction areas, and installing sound insulation components on subway floors in localized noise reduction areas;

[0023] The acoustic energy of some noise inside the subway car is converted into electrical energy to power the local noise reduction area.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) This solution installs the opening of the noise reduction cover body on the side wall of the subway, so that the cover of the noise reduction cover body is set on the subway seat, completing the partial enclosure of the subway seat; a Holmtz generator is installed in the noise reduction cavity formed by the outer shell and the inner shell, and sound collecting holes and air holes are set on the noise reduction cover body to ensure that the noise reduction cover body is breathable. At the same time, the Holmtz generator between the two converts the sound energy in the sound collecting holes into electrical energy, thereby reducing the noise inside the noise reduction cover body.

[0026] By installing a double-layered noise reduction cover on the seat, utilizing the ventilation holes on the cover to ensure air circulation inside the cover, and using the Holmz generator installed in the sound collection hole to convert the sound energy of the noise into electrical energy, the double-layered noise reduction cover can also play a role in assisting noise reduction on the seat. The noise reduction cover can reduce noise locally, providing a healthy environment for special groups of people, with good noise reduction effect, simple structure and low cost.

[0027] (2) This solution can assist in absorbing the noise generated by the friction and vibration between the subway wheels and the tracks when they run along the tracks by installing sound insulation pads on the subway floor, thereby further improving the noise reduction effect of the subway car noise reduction cover.

[0028] (3) In this plan, local noise reduction areas are reasonably selected according to the passenger density in each area of ​​the subway, and noise reduction covers with Holmtz generators are set up in areas with low passenger density to convert the noise energy around the local noise reduction areas into electrical energy. While reducing noise, it can also generate electrical energy for use in the local noise reduction areas, reducing the use of additional energy and being more economical and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of the subway car noise reduction cover provided by the present invention from a first perspective;

[0030] Figure 2 A schematic structural diagram of the subway car noise reduction cover provided by the present invention from a second perspective;

[0031] Figure 3 A cross-sectional view of the subway car noise reduction cover provided by the present invention;

[0032] Figure 4 A schematic diagram of the Holmtz generator provided by the present invention;

[0033] In the figure: 1. Noise reduction cover body, 2. Holmz generator, 3. Enclosed door, 4. Ventilation fan, 5. Sound insulation pad, 11. Sound collecting hole, 12. Air vent, 21. Neck, 22. Cavity, 23. Vibrating film, 24. Electret, 25. Electrode, 26. Battery, 27. Load. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition or explanation in subsequent drawings.

[0037] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0038] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0039] Furthermore, terms such as "horizontal" and "vertical" do not necessarily mean that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0040] Example 1

[0041] like Figures 1 to 3 As shown, this embodiment provides a subway car noise reduction cover based on sound energy conversion, including a noise reduction cover body 1 and a Holmz generator 2;

[0042] The noise reduction cover body 1 is installed on the subway seat, and the open end of the noise reduction cover body 1 is fixed to the side wall of the subway. The noise reduction cover body 1 is a double-layer structure, including an outer shell and an inner shell, and an auxiliary noise reduction cavity is formed between the outer shell and the inner shell;

[0043] The Holmtz generator 2 is installed in the auxiliary noise reduction cavity. The noise reduction cover body 1 is provided with a sound collecting hole 11 and a vent hole 12 . The Holmtz generator 2 is located in the sound collecting hole 11 .

[0044] Working principle: The opening of the noise reduction cover body 1 is installed on the side wall of the subway, so that the cover of the noise reduction cover body 1 is set on the subway seat to complete the partial enclosure of the subway seat; the Holmtz generator 2 is installed in the noise reduction cavity formed by the outer shell and the inner shell, and sound collecting holes and air holes are set on the noise reduction cover body 1, wherein the size of the air holes can be adjusted according to the size of the noise reduction structure to make the air flow in the noise reduction cover smooth, ensuring that the noise reduction cover body 1 is breathable, while the Holmtz generator 2 converts the sound energy in the sound collecting holes into electrical energy, thereby reducing the noise in the noise reduction cover body 1.

[0045] By installing a double-layered noise reduction cover body 1 on the seat, utilizing the ventilation holes on the noise reduction cover body 1 to ensure air circulation inside the noise reduction cover body 1, and converting the sound energy of the noise into electrical energy through the Holmz generator 2 installed in the sound collection hole, the noise reduction cover body 1 is provided with air circulation and noise reduction treatment is performed inside the noise reduction cover body 1. The double-layered noise reduction cover body 1 can also play a role in assisting noise reduction on the seat. The noise reduction cover can reduce noise locally, providing a healthy environment for special groups of people, has good noise reduction effect, and has a simple structure and low cost.

[0046] like Figure 4 As shown, the specific steps and principles of the Holmz acoustic energy generator to convert noise into electrical energy are as follows:

[0047] The Holmholtz generator 2 is based on the sound energy absorption characteristics of the Holmholtz resonator and combines the energy conversion mechanism of piezoelectric materials. Its core structure includes: a neck 21: an entrance for sound waves with a small diameter; a cavity 22: a closed space connected to the neck, with a built-in piezoelectric material layer: including a vibrating film 23 and an electret 24; and an air vent: an additional opening for balancing airflow and affecting the resonant main frequency.

[0048] The conversion of sound wave energy includes the following steps:

[0049] Step 1: Acoustic Wave Capture and Resonance Tuning

[0050] Sound wave capture: External noise enters the neck of the Holmtz resonator through the sound collecting holes of the noise reduction cover, which corresponds to the sound collecting holes in this embodiment receiving the noise;

[0051] Resonance tuning: When the noise frequency f approaches the natural frequency f0 of the resonator, violent gas oscillations occur in the cavity. The expression of the natural frequency f0 is:

[0052]

[0053] Where c is the speed of sound, the propagation speed of sound waves in air at room temperature is about 343m / s, A is the cross-sectional area of ​​the neck, V is the volume of the Holmz resonant cavity, L is eff =L+1.7r represents the effective length of the neck, L is the actual length of the neck, and r is the radius of the neck.

[0054] Step 2: Mechanical Energy Conversion

[0055] Cavity pressure fluctuations: The periodic pressure changes generated by resonance drive the piezoelectric material (such as PVDF film or piezoelectric ceramic) in the resonator cavity to deform;

[0056] Piezoelectric effect: When a piezoelectric material is deformed by force, its internal electric dipole moment changes and charges are generated on the surface. The charge generation expression is:

[0057] D=d×T+∈×E

[0058] Where d is the piezoelectric constant, T is the mechanical stress, ∈ is the node constant, and E is the electric field intensity.

[0059] Step 3: Power Collection and Output

[0060] Electrode collection: The electrodes 25 attached to both sides of the piezoelectric material collect the charge and form a current output;

[0061] Circuit storage: The AC power is converted into DC power through a full-bridge rectifier circuit and stored in a supercapacitor or battery 26 to power the load 27.

[0062] The significance and function of each parameter in the Holmz power generation structure are shown in Table 1.

[0063] Table 1

[0064] parameter Typical values effect <![CDATA[Resonant frequency f0]]> 150Hz Optimized for subway low-frequency noise Piezoelectric film thickness 0.2mm(PVDF) Balance of sensitivity and durability Single device output power 0.5~3mW Powering LED lighting or sensors Noise Reduction Amount (IL) 8~12dB Peak frequency band (below 200Hz)

[0065] The specific steps of noise reduction through the Holmtz generator in this embodiment are: collecting the external noise of the soundproof cover into the Holmtz resonant cavity through the sound collecting hole, performing resonance boosting to make the piezoelectric film vibrate, and then extracting the AC current through charge separation. In conjunction with the rectifier circuit, the electric energy generated by the Holmtz generator is input into the energy storage battery for use by local equipment, and the noise of the soundproof cover is reduced. At the same time, the residual sound wave energy is absorbed by the cavity to achieve the noise reduction effect.

[0066] It should be noted that the double-layered noise reduction cover body 1 provided in this embodiment, with its Holmz generator 2, is designed to reduce excessively high decibel noise to a level relatively harmless to humans, thereby protecting passengers. It does not isolate the sounds within the subway, but the degree of protection provided is essentially the same, with lower cost and greater practicality.

[0067] Specifically, an inlet and outlet are provided on the noise reduction cover body 1, and a closed door 3 of matching shape is provided inside the inlet and outlet. The closed door 3 is movably installed inside the inlet and outlet, and a sealing strip is provided between the closed door 3 and the inlet and outlet, thereby improving the noise reduction effect inside the noise reduction cover body 1.

[0068] The Holmtz generator 2 includes a Holmtz resonance cavity, a diaphragm, a magnet and a coil;

[0069] The Holmtz resonance cavity is a funnel-shaped structure. The inlet end of the Holmtz resonance cavity faces the sound collecting hole. The diaphragm is installed at the outlet end of the Holmtz resonance cavity. The coil is wound on the magnetic steel and the diaphragm covers the magnetic steel.

[0070] In this embodiment, the material of the noise reduction cover body 1 is PC board. PC board has excellent sound insulation, flame retardancy, and transparency. It can be placed around the seat area inside the vehicle to effectively reduce noise, and can also be seen into the outside space and the interior space, ensuring the safety of the interior of the sound insulation cover.

[0071] In a preferred embodiment, a sound insulation pad 5 is provided inside the noise reduction cover body 1. The sound insulation pad 5 is provided on the subway floor to absorb the noise generated by the friction and vibration between the wheels and the track. The material of the sound insulation pad 5 includes polyurethane rubber or polyethylene.

[0072] By arranging the sound insulation pad 5 on the subway floor, it can assist in absorbing the noise generated by the friction and vibration between the subway wheels and the tracks when running along the tracks, and further improve the noise reduction effect of the subway car noise reduction cover.

[0073] The noise reduction enclosure body 1 houses a display screen and speakers, which are mounted on the subway's sidewall. Batteries are electrically connected to the screen and speakers, respectively. The display screen, mounted above the entrance and exit of the enclosure, displays real-time data such as the current and next station names and the interior temperature of the carriage. It is located in front of passengers inside the enclosure for easy viewing.

[0074] Specifically, the Holmz generator 2 is connected to a battery. A ventilation fan is provided inside the noise reduction cover body 1. The ventilation fan is located in the air vent 12 and is electrically connected to the battery.

[0075] The electric energy generated by the Holmz generator 2 is stored in a battery to supply power to electrical appliances in the noise reduction area or other areas, thereby reducing the consumption of additional energy for the subway and being more economical and environmentally friendly.

[0076] This embodiment also provides a noise reduction method for a subway car noise reduction cover based on sound energy conversion, comprising the following steps:

[0077] Determine local noise reduction areas on the subway based on the passenger density in each area of ​​the subway;

[0078] Installing noise reduction covers with Holmz generators on seats in localized noise reduction areas, and installing sound insulation components on subway floors in localized noise reduction areas;

[0079] The acoustic energy of some noise inside the subway car is converted into electrical energy to power the local noise reduction area.

[0080] Based on the density of pedestrian traffic in various areas of the subway, local noise reduction areas are reasonably selected, with priority given to areas with relatively low pedestrian density to avoid affecting the riding experience of other passengers. In areas with low pedestrian density, noise reduction covers with Holmz generators are installed to convert the noise energy around the local noise reduction areas into electrical energy. While reducing noise, they can also generate electricity for use in the local noise reduction areas, reducing the use of additional energy and making it more economical and practical. Compared with directly dealing with the mutual coupling between the wheels and rails of rail transit vehicles (i.e., dealing with noise at the sound source), this can reduce costs, save time, and be more efficient.

[0081] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A subway car noise reduction cover based on sound energy conversion, characterized in that: It comprises a noise reduction cover body (1) and a Holmes generator (2); The noise reduction cover body (1) is mounted on a subway seat, the open end of the noise reduction cover body (1) is fixed on a subway side wall, the noise reduction cover body (1) is a double-layer structure, comprising an outer shell and an inner shell, and an auxiliary noise reduction cavity is formed between the outer shell and the inner shell; The Holmtz generator (2) is installed in the auxiliary noise reduction cavity, the noise reduction cover body (1) is provided with a sound collecting hole (11) and a vent hole (12), and the Holmtz generator (2) is located in the sound collecting hole.

2. The subway car noise reduction cover based on sound energy conversion according to claim 1 is characterized in that: The noise reduction cover body (1) is provided with an inlet and an outlet, a closed door (3) of matching shape is provided inside the inlet and an inlet is movably installed inside the inlet and an airtight strip is provided between the closed door (3) and the inlet and an outlet.

3. The subway car noise reduction cover based on sound energy conversion according to claim 1 is characterized in that: The Holmitz generator (2) comprises a Holmitz resonance cavity, a diaphragm, a magnetic steel and a coil; The Holmtz resonance cavity is a funnel-shaped structure, the inlet end of the Holmtz resonance cavity is directly opposite to the sound collecting hole, the diaphragm is installed at the outlet end of the Holmtz resonance cavity, the coil is wound on the magnetic steel, and the diaphragm covers the magnetic steel.

4. The subway car noise reduction cover based on sound energy conversion according to claim 1 is characterized in that: The material of the noise reduction cover body (1) is a PC board.

5. The subway car noise reduction cover based on sound energy conversion according to claim 1 is characterized in that: A sound insulation pad (5) is provided inside the noise reduction cover body (1); the sound insulation pad (5) is arranged on the subway floor and is used to absorb the noise generated by the friction and vibration between the wheels and the rails.

6. The subway car noise reduction cover based on sound energy conversion according to claim 5 is characterized in that: The material of the sound insulation pad (5) includes polyurethane rubber or polyethylene.

7. The subway car noise reduction cover based on sound energy conversion according to claim 1 is characterized in that: The Holmes generator (2) is connected to a battery.

8. The subway car noise reduction cover based on sound energy conversion according to claim 7 is characterized in that: A display screen and a sound system are arranged inside the noise reduction cover body (1); the display screen and the sound system are mounted on the side wall of the subway; and the storage battery is electrically connected to the display screen and the sound system respectively.

9. The subway car noise reduction cover based on sound energy conversion according to claim 7, characterized in that: A ventilation fan (4) is provided inside the noise reduction cover body (1); the ventilation fan (4) is located in the air vent and is electrically connected to a storage battery.

10. A noise reduction method for a subway car noise reduction cover based on sound energy conversion according to any one of claims 1 to 9, characterized in that: The following steps are involved: Determine the local noise reduction areas on the subway based on the passenger density in each area of ​​the subway; The seats in the local noise reduction area are covered with noise reduction covers with Holmes generators, and sound insulation components are installed on the subway floor surface in the local noise reduction area; The acoustic energy of some noise inside the subway car is converted into electrical energy to provide power for local noise reduction areas.

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