Noise reduction equipment and method for fan in terminal

Abstract

The embodiment of the invention relates to noise reduction equipment and method for a fan in a terminal. The noise reduction equipment comprises a first air duct, at least one noise reduction air duct and a switch combination. One end of the first air duct is connected with a fan air outlet, and the other end of the first air duct is connected with a terminal air outlet; one end of the noise reduction air duct is connected with the fan air outlet, and the other end of the noise reduction air duct is connected with the terminal air outlet; switches in the switch combination are arranged at an air inlet and an air outlet of the noise reduction air duct, and the switch combination is used for controlling the noise reduction air duct to be opened or closed; the air channel length difference between the first air channel and the noise reduction air channel is nL + L / 2, n is a natural number, and L is the wind noise wavelength at the air outlet of the fan. According to the embodiment of the invention, the wind noise at the air outlet of the terminal is mutually counteracted, so that the wind noise is reduced.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of terminals, and in particular, to a noise reduction device and method for a fan in a terminal. Background Art

[0002] Currently, products such as mobile phones, CPE (Customer Premise Equipment), tablet computers, and laptops will generate heat during use, so the terminals need to be cooled.

[0003] The current cooling method is to install a fan inside the terminal. The wind generated by the fan will generate noise when it is transmitted to the terminal outlet, affecting the user experience. Summary of the invention

[0004] The embodiments of the present application provide a noise reduction device and method for a fan in a terminal, so as to at least solve the problem of noise generated by fan cooling.

[0005] In the first aspect, an embodiment of the present application provides a noise reduction device for a fan in a terminal, the noise reduction device comprising: a first air duct, at least one noise reduction air duct and a switch combination; one end of the first air duct is connected to the fan outlet, and the other end of the first air duct is connected to the terminal outlet; one end of the noise reduction air duct is connected to the fan outlet, and the other end of the noise reduction air duct is connected to the terminal outlet; the switches in the switch combination are arranged at the air inlet and air outlet of the noise reduction air duct, and the switch combination is used to control the opening or closing of the noise reduction air duct; the air duct length difference between the first air duct and the noise reduction air duct is nL+L / 2, where n is a natural number and L is the wavelength of wind noise at the fan outlet.

[0006] In a second aspect, an embodiment of the present application provides a noise reduction method for a fan in a terminal, the method comprising: obtaining a current gear position at the fan outlet, wherein different gear positions correspond to different wind speeds; based on a preset mapping relationship, turning on a target noise reduction air duct corresponding to the current gear position by a control switch, wherein the preset mapping relationship indicates that different gear positions correspond to noise reduction air ducts of different lengths; through a first air duct with a fixed length and the target noise reduction air duct, the air outlet at the fan outlet is delivered to the terminal outlet, so that the waveforms of the wind noise generated by the first air duct and the target noise reduction air duct at the terminal outlet are consistent, and the waveform phase difference is m 180°, wherein m is a positive integer.

[0007] In the third aspect, an embodiment of the present application provides an electronic device, comprising: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor connected to the at least one bus; at least one memory connected to the at least one bus, wherein the processor is configured to: obtain the current gear position at the fan outlet, wherein different gear positions correspond to different wind speeds; based on a preset mapping relationship, turn on the target noise reduction air duct corresponding to the current gear position through a control switch, wherein the preset mapping relationship indicates that different gear positions correspond to noise reduction air ducts of different lengths; through a first air duct of a fixed length and the target noise reduction air duct, the air outlet at the fan outlet is delivered to the terminal air outlet, so that the waveform of the wind noise generated by the first air duct and the target noise reduction air duct at the terminal air outlet is consistent, and the waveform phase difference is m 180°, wherein m is a positive integer.

[0008] In a fourth aspect, an embodiment of the present application further provides a computer storage medium storing computer executable instructions, wherein the computer executable instructions are used to execute the method for reducing noise of a fan in a terminal as described in any one of the above items of the present application.

[0009] The embodiment of the present application sets noise reduction air ducts of different lengths corresponding to each gear position of the fan, and can open the corresponding target noise reduction air duct according to the current gear position, thereby dividing the same wind into two paths, so that the wind reaches the terminal air outlet from the first air duct and the target noise reduction air duct respectively, forming a waveform with a consistent waveform and a waveform phase difference of m 180° at the terminal air outlet, so that the two winds cancel out the wind noise and reduce the wind noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0011] 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, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0012] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0013] Figure 1 A schematic diagram of a noise reduction device for a fan in a terminal provided in an embodiment of the present application;

[0014] Figure 2 A flow chart of a method for reducing noise of a fan in a terminal provided in an embodiment of the present application;

[0015] Figure 3 A schematic diagram of the air duct opening control process at three fan gears provided in an embodiment of the present application;

[0016] Figure 4 A schematic diagram of the structure of a noise reduction device for a fan in a terminal provided in an embodiment of the present application;

[0017] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0019] The disclosure below provides many different embodiments or examples to realize the different structures of the embodiments of the present invention. In order to simplify the disclosure of the embodiments of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the embodiments of the present invention. In addition, the embodiments of the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0020] The embodiment of the present application provides a noise reduction device for a fan in a terminal, such as Figure 1 As shown, the noise reduction device includes: a first air duct, at least one noise reduction air duct and a switch combination.

[0021] One end of the first air duct is connected to the fan outlet, and the other end of the first air duct is connected to the terminal outlet, and is used to send the wind from the fan outlet to the terminal outlet. The first air duct is the air duct where the fan outlet normally flows. Figure 1 As shown, the first air duct is the leftmost air duct.

[0022] One end of the noise reduction air duct is connected to the fan outlet, and the other end of the noise reduction air duct is connected to the terminal outlet. The noise reduction air duct may be one or more. The air duct length difference between each noise reduction air duct and the first air duct is nL+L / 2, where n is a natural number, and L is the wavelength of wind noise at the fan outlet. Figure 1As shown, the noise reduction air duct includes noise reduction air duct ①, noise reduction air duct ② and noise reduction air duct ③ on the right.

[0023] The switches in the switch combination are arranged at the air inlet and the air outlet of the noise reduction air duct, and the switch combination is used to control the opening or closing of the noise reduction air duct, that is, the first air duct can be opened at the same time as one noise reduction air duct, or the first air duct and multiple noise reduction air ducts can be opened at the same time.

[0024] Since the length of the air duct between the first air duct and the noise reduction air duct differs by nL+L / 2, the time when the wind from the fan outlet reaches the terminal outlet from the noise reduction air duct is nT+T / 2 later than the time when the wind from the first air duct reaches the terminal outlet, where T is the period of the waveform, that is, the waveform of the wind in the first air duct and the waveform of the wind in the noise reduction air duct at the terminal outlet are consistent and have a phase difference of m*180°, and the wind noise formed by the two winds cancel each other out, thereby achieving the function of reducing wind noise. Where m is a positive integer.

[0025] Whether one or multiple noise reduction ducts are opened, since the duct length between each noise reduction duct and the first duct differs by nL+L / 2, the phase of the wind waveform of the noise reduction duct and the wind waveform of the first duct differs by m*180°.

[0026] The embodiment of the present application sets a plurality of switches, and the setting method of the switches includes at least the following two embodiments.

[0027] In one embodiment, a switch is provided at the air inlet or outlet of each noise reduction air duct, and the switch is used to open or close the noise reduction air duct.

[0028] In another embodiment, the same switch is used between the air inlets or air outlets of two adjacent noise reduction air ducts, and the switch is used to open one noise reduction air duct while closing the other noise reduction air duct.

[0029] Exemplarily, the noise reduction device includes a first noise reduction air duct, a second noise reduction air duct and a third noise reduction air duct, the air duct lengths of which increase sequentially, and the first noise reduction air duct, the second noise reduction air duct and the third noise reduction air duct are sequentially arranged in parallel.

[0030] A switch is provided between the air inlet of the first noise reduction air duct and the air inlet of the second noise reduction air duct, and a switch is provided between the air outlet of the first noise reduction air duct and the air outlet of the second noise reduction air duct. By turning the switch between the first noise reduction air duct and the second noise reduction air duct, only the first noise reduction air duct is closed and the second noise reduction air duct is opened, so that the wind passes through the second noise reduction air duct; or by turning the switch between the first noise reduction air duct and the second noise reduction air duct, only the second noise reduction air duct is closed and the first noise reduction air duct is opened, so that the wind passes through the first noise reduction air duct.

[0031] A switch is provided between the air inlet of the second noise reduction air duct and the air inlet of the third noise reduction air duct, and a switch is provided between the air outlet of the second noise reduction air duct and the air outlet of the third noise reduction air duct. By toggling the switch between the second noise reduction air duct and the third noise reduction air duct, only the second noise reduction air duct is closed and the third noise reduction air duct is opened, so that the wind passes through the third noise reduction air duct; or by toggling the switch between the second noise reduction air duct and the third noise reduction air duct, only the third noise reduction air duct is closed and the second noise reduction air duct is opened, so that the wind passes through the second noise reduction air duct.

[0032] Optionally, the shape of the first air duct is any one of a straight line shape, an arc shape or a bent shape, and the shape of the noise reduction air duct is any one of a straight line shape, an arc shape or a bent shape. The specific shape of the air duct is designed according to the internal structure of the terminal device and is not limited in the embodiments of the present application.

[0033] Based on the same technical concept, the embodiment of the present application also proposes a noise reduction method for a fan in a terminal, such as Figure 2 As shown, the method includes:

[0034] Step 201: Obtain the current gear position at the fan outlet.

[0035] Among them, different gears correspond to different wind speeds.

[0036] A fan for heat dissipation is provided inside the terminal. Different gears of the fan correspond to different wind speeds. The terminal obtains the current gear at the fan outlet.

[0037] Step 202: Based on a preset mapping relationship, the target noise reduction air duct corresponding to the current gear position is turned on by controlling the switch.

[0038] Among them, the preset mapping relationship indicates that different gears correspond to noise reduction air ducts of different lengths.

[0039] The terminal obtains the wind noise frequency of the wind speed corresponding to the current gear at the fan outlet, and then determines the wind noise wavelength of the wind speed according to the preset coefficient u and the wind noise frequency. The calculation formula of the wind noise wavelength is λ=u / f, where λ is the wind noise wavelength, u is the wave speed, and f is the wind noise frequency.

[0040] Since the same wind at the fan outlet flows through the first air duct and the noise reduction air duct, the wind noise frequency and wind noise wavelength of the first air duct and the noise reduction air duct are the same.

[0041] The terminal determines the duct length of the noise reduction duct according to the wind noise wavelength and the duct length of the first duct, thereby ensuring that the duct length of the noise reduction duct differs from the duct length of the first duct by nL+L / 2, where n is a natural number, L is the wind noise wavelength,

[0042] In this way, the terminal obtains the duct length of the noise reduction air duct corresponding to the current gear. The above operation is performed for each gear of the fan to obtain the duct length of the noise reduction air duct corresponding to each gear, thereby establishing a mapping relationship between the fan gear and the duct length of the noise reduction air duct, and saving the mapping relationship.

[0043] After the fan is turned on, the terminal determines the target noise reduction air duct corresponding to the current gear of the fan according to the preset mapping relationship, and turns on the target noise reduction air duct through the control switch, so that only the first air duct and the target noise reduction air duct are turned on, and other noise reduction air ducts are closed.

[0044] Step 203: The air at the fan outlet is delivered to the terminal outlet through a first air duct and a target noise reduction air duct of fixed length, so that the waveforms of the wind noise generated by the first air duct and the target noise reduction air duct at the terminal outlet are consistent, and the waveform phase difference is m 180°, where m is a positive integer.

[0045] The air outlet of the fan is divided into two paths. One path passes through the first air duct of fixed length from the fan outlet to the terminal outlet, and the other path passes through the target noise reduction air duct from the fan outlet to the terminal outlet. The waveforms of the wind noise generated by the two paths at the terminal outlet are consistent, and the phase difference of the waveforms is m 180°. The wind noises cancel each other out, and finally the wind noise heard at the terminal outlet is reduced.

[0046] The embodiment of the present application sets noise reduction air ducts of different lengths corresponding to each gear position of the fan, and can open the corresponding target noise reduction air duct according to the current gear position, thereby dividing the same wind into two paths, so that the wind reaches the terminal air outlet from the first air duct and the target noise reduction air duct respectively, forming a waveform with a consistent waveform and a waveform phase difference of m 180° at the terminal air outlet, so that the two winds cancel out the wind noise and reduce the wind noise.

[0047] Exemplarily, the gears include a first gear, a second gear, and a third gear whose corresponding wind speeds decrease in sequence, the noise reduction air duct includes a first noise reduction air duct, a second noise reduction air duct, and a third noise reduction air duct whose air duct lengths increase in sequence, and based on a preset mapping relationship, opening the target noise reduction air duct corresponding to the current gear by controlling the switch includes the following three embodiments.

[0048] In the first embodiment, when it is detected that the current gear position is the first gear position, the second noise reduction air duct and the third noise reduction air duct are closed by controlling the switch, and the first noise reduction air duct is opened.

[0049] In the second embodiment, when it is detected that the current gear position is the second gear position, the first noise reduction air duct and the third noise reduction air duct are closed by controlling the switch, and the second noise reduction air duct is opened.

[0050] In the third embodiment, when it is detected that the current gear position is the third gear position, the first noise reduction air duct and the second noise reduction air duct are closed by controlling the switch, and the third noise reduction air duct is opened.

[0051] Combine the following Figure 1 The embodiments of the present application are explained in detail.

[0052] The fan has three gears: high, medium and low. The fan is wrapped by an external structure, and the wind generated can only start from the fan outlet and flow to the terminal outlet in a fixed direction through the air duct. The left side below the fan is the first air duct with normal flow, and the right side is the noise reduction air duct ①, noise reduction air duct ② and noise reduction air duct ③. There are two switches on the upper and lower parts of the noise reduction air duct, which can be turned to the horizontal and vertical states to close and open different noise reduction channels.

[0053] When the fan rotates at high speed, the corresponding wind speed is A1, the wind noise frequency generated is the highest, which is f1, the wavelength of the wind noise waveform is L1, the wavelength is the shortest, and the period is T1. Therefore, the noise reduction flow direction flows to the terminal air outlet through the shortest noise reduction air duct ①. At this time, it is necessary to turn the air duct switch 1 to the vertical upward direction, turn the air duct switch 4 to the vertical downward direction, close the noise reduction air duct ③, turn the air duct switch 2 to the vertical upward direction, turn the air duct switch 3 to the vertical downward direction, close the noise reduction air duct ②, and ensure that the wind flows from the noise reduction air duct ① to the terminal air outlet. The wind flows from the noise reduction air duct ① to the terminal air outlet, and arrives at the terminal air outlet position nT1+T1 / 2 later than the wind in the first air duct. Therefore, the wind noise waveform that reaches the air outlet position through the two air ducts is basically straight, with a phase difference of m 180°. The wind noise formed by the two winds cancels each other out, achieving the function of reducing wind noise.

[0054] When the fan is working at medium speed, the corresponding wind speed is A2, the frequency of wind noise generated is f2, the wavelength of wind noise waveform is L2, the wavelength is medium, and the period is T2. Therefore, the noise reduction flow direction flows to the terminal outlet through the medium-length noise reduction air duct ②. At this time, it is necessary to turn the air duct switch 1 to the vertical upward direction, turn the air duct switch 4 to the vertical downward direction, close the noise reduction air duct ③, turn the air duct switch 2 to the horizontal left direction, and turn the air duct switch 3 to the horizontal left direction to close the noise reduction air duct ①, so as to ensure that the wind flows from the noise reduction air duct ② to the terminal outlet position. The wind flows from the noise reduction air duct ② to the terminal outlet, and arrives at the terminal outlet position nT2+T2 / 2 later than the wind flowing to the air duct normally. Therefore, the wind noise waveform that reaches the terminal outlet position through the two air ducts is basically straight, with a phase difference of m 180°. The wind noise formed by the two winds cancels each other out, achieving the function of reducing wind noise.

[0055] When the fan is working at a low gear, the corresponding wind speed is A3, the frequency of the wind noise generated is f3, the wavelength of the wind noise waveform is L3, the wavelength is the largest, and the period is T3. Therefore, the noise reduction flow direction flows to the terminal outlet through the longest noise reduction air duct ③. At this time, it is necessary to turn the air duct switch 1 to the horizontal left direction, turn the air duct switch 4 to the horizontal left direction, close the noise reduction air duct ②, and ensure that the wind flows from the noise reduction air duct ③ to the terminal outlet position. The wind flows from the noise reduction air duct ③ to the terminal outlet, and arrives at the terminal outlet position nT3+T3 / 2 later than the wind flowing to the air duct normally. Therefore, the wind noise waveform that reaches the terminal outlet position through the two air ducts is basically straight, with a phase difference of m 180°. The wind noise formed by the two winds cancels each other out, achieving the function of reducing wind noise.

[0056] Figure 3 Schematic diagram of the air duct opening control process at three fan gears.

[0057] Compared with the prior art, the embodiment of the present application does not use MIC and speakers for active noise reduction, and does not need to add MIC and speakers and other auxiliary circuits, so the cost will not increase significantly. At the same time, no MIC and speakers are added inside the mobile phone, which will not interfere with the antenna and radio frequency indicators and will not increase the design difficulty.

[0058] Based on the same technical concept, the embodiment of the present application provides a noise reduction device for a fan in a terminal, such as Figure 4 As shown, the device comprises:

[0059] An acquisition module 401 is used to acquire the current gear position at the fan outlet, wherein different gear positions correspond to different wind speeds;

[0060] An opening module 402 is used to open the target noise reduction air duct corresponding to the current gear position by controlling the switch based on a preset mapping relationship, wherein the preset mapping relationship indicates that different gear positions correspond to noise reduction air ducts of different lengths;

[0061] The transmission module 403 is used to deliver the air at the fan outlet to the terminal outlet through a first air duct and a target noise reduction air duct of fixed length, so that the waveforms of the wind noise generated by the first air duct and the target noise reduction air duct at the terminal outlet are consistent, and the waveform phase difference is m 180°, where m is a positive integer.

[0062] Optionally, the start module 402 is used to:

[0063] Determine the wind noise frequency corresponding to the wind speed at the fan outlet at the current gear;

[0064] Determine the wind noise wavelength of the wind speed according to the preset coefficient and wind noise frequency;

[0065] Determine the length of the noise reduction duct according to the wind noise wavelength and the duct length of the first duct, wherein the difference between the duct length of the noise reduction duct and the duct length of the first duct is nL+L / 2, wherein n is a natural number and L is the wind noise wavelength;

[0066] A mapping relationship between the gear position and the air duct length of the noise reduction air duct is established.

[0067] Optionally, the gear position includes a first gear position, a second gear position and a third gear position corresponding to successively decreasing wind speeds, the noise reduction air duct includes a first noise reduction air duct, a second noise reduction air duct and a third noise reduction air duct whose air duct lengths successively increase, and the opening module 402 is used to:

[0068] When it is detected that the current gear position is the first gear position, the second noise reduction air duct and the third noise reduction air duct are closed by controlling the switch, and the first noise reduction air duct is opened; or,

[0069] When it is detected that the current gear position is the second gear position, the first noise reduction air duct and the third noise reduction air duct are closed by controlling the switch, and the second noise reduction air duct is opened; or,

[0070] When it is detected that the current gear position is the third gear position, the first noise reduction air duct and the second noise reduction air duct are closed by controlling the switch, and the third noise reduction air duct is opened.

[0071] like Figure 5 As shown, an embodiment of the present application provides an air conditioner control device, including a processor 501, a communication interface 502, a memory 503 and a communication bus 504, wherein the processor 501, the communication interface 502, and the memory 503 communicate with each other through the communication bus 504.

[0072] The memory 503 is used to store computer programs.

[0073] In one embodiment of the present application, the processor 501 is used to implement the fan noise reduction method in the terminal provided by any one of the aforementioned method embodiments when executing the program stored in the memory 503.

[0074] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the method for reducing noise of a fan in a terminal provided in any one of the aforementioned method embodiments are implemented.

[0075] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0076] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course, by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the relevant technology can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0077] It should be understood that the terms used in the text are only for the purpose of describing specific example embodiments, and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used in the text may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0078] The above description is only a specific implementation of the embodiments of the present invention, so that those skilled in the art can understand or implement the embodiments of the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A noise reduction device for a fan in a terminal, characterized in that: The noise reduction device comprises: a first air duct, at least one noise reduction air duct and a switch combination; One end of the first air duct is connected to the fan air outlet, and the other end of the first air duct is connected to the terminal air outlet; One end of the noise reduction air duct is connected to the fan air outlet, and the other end of the noise reduction air duct is connected to the terminal air outlet; The switches in the switch combination are arranged at the air inlet and the air outlet of the noise reduction air duct, and the switch combination is used to control the opening or closing of the noise reduction air duct; The difference in air duct length between the first air duct and the noise reduction air duct is nL+L / 2, where n is a natural number and L is the wavelength of wind noise at the fan outlet.

2. The noise reduction device according to claim 1, characterized in that: The same switch is used between the air inlets or air outlets of two adjacent noise reduction air ducts, and the switch is used to open one noise reduction air duct while closing the other noise reduction air duct.

3. The noise reduction device according to claim 1, characterized in that: Each air inlet or air outlet of the noise reduction air duct is provided with a switch, and the switch is used to open or close the noise reduction air duct.

4. The noise reduction device according to claim 2, characterized in that: The noise reduction device comprises a first noise reduction air duct, a second noise reduction air duct and a third noise reduction air duct with increasing air duct lengths in sequence; The first noise reduction air duct, the second noise reduction air duct and the third noise reduction air duct are arranged in parallel in sequence; A switch is provided between the air inlet of the first noise reduction air duct and the air inlet of the second noise reduction air duct, and a switch is provided between the air inlet of the second noise reduction air duct and the air inlet of the third noise reduction air duct; A switch is provided between the air outlet of the first noise reduction air duct and the air outlet of the second noise reduction air duct, and a switch is provided between the air outlet of the second noise reduction air duct and the air outlet of the third noise reduction air duct.

5. The noise reduction device according to claim 1, characterized in that: The first air duct and / or the noise reduction air duct has a straight line shape, an arc shape or a bent shape.

6. A method for reducing noise of a fan in a terminal, characterized in that: The method comprises: Get the current gear position at the fan outlet, where different gear positions correspond to different wind speeds; Based on a preset mapping relationship, the target noise reduction air duct corresponding to the current gear position is turned on by controlling the switch, wherein the preset mapping relationship indicates that different gear positions correspond to noise reduction air ducts of different lengths; The air outlet at the fan outlet is delivered to the terminal outlet through a first air duct of a fixed length and the target noise reduction air duct, so that the waveforms of the wind noise generated by the first air duct and the target noise reduction air duct at the terminal outlet are consistent, and the waveform phase difference is m 180°, where m is a positive integer.

7. The method according to claim 6, characterized in that Based on the preset mapping relationship, the target noise reduction air duct corresponding to the current gear position is turned on by controlling the switch, and the method further includes: Determine the wind noise frequency of the fan at the current gear corresponding to the wind speed at the fan outlet; Determining the wind noise wavelength of the wind speed according to a preset coefficient and the wind noise frequency; Determine the length of the noise reduction duct according to the wind noise wavelength and the length of the first duct, wherein the difference between the length of the noise reduction duct and the length of the first duct is nL+L / 2, wherein n is a natural number and L is the wind noise wavelength; A mapping relationship between the gear position and the air duct length of the noise reduction air duct is established.

8. The method according to claim 6, characterized in that The gears include a first gear, a second gear, and a third gear corresponding to successively decreasing wind speeds, the noise reduction air duct includes a first noise reduction air duct, a second noise reduction air duct, and a third noise reduction air duct whose air duct lengths successively increase, and based on the preset mapping relationship, opening the target noise reduction air duct corresponding to the current gear by controlling the switch includes: When it is detected that the current gear position is the first gear position, the second noise reduction air duct and the third noise reduction air duct are closed by controlling the switch, and the first noise reduction air duct is opened; or, When it is detected that the current gear position is the second gear position, the first noise reduction air duct and the third noise reduction air duct are closed by controlling the switch, and the second noise reduction air duct is opened; or, When it is detected that the current gear position is the third gear position, the first noise reduction air duct and the second noise reduction air duct are closed by controlling the switch, and the third noise reduction air duct is opened.

9. An electronic device, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; Memory, used to store computer programs; A processor, for implementing any of the methods described in claims 6-8 when executing a program stored in a memory.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 6 to 8 is implemented.

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