CN107725487B - Noise reduction device for fan - Google Patents
Noise reduction device for fan Download PDFInfo
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- CN107725487B CN107725487B CN201711203585.7A CN201711203585A CN107725487B CN 107725487 B CN107725487 B CN 107725487B CN 201711203585 A CN201711203585 A CN 201711203585A CN 107725487 B CN107725487 B CN 107725487B
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- noise reduction
- fan
- air outlet
- noise
- pickup
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
- F04D29/661—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for elastic fluid pumps
- F04D29/663—Sound attenuation
- F04D29/665—Sound attenuation by means of resonance chambers or interference
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
The invention provides a noise reduction device for a fan, which comprises an active noise reduction assembly and a passive noise reduction assembly, wherein the passive noise reduction assembly is a sound elimination cover with a hyperboloid; the active noise reduction assembly comprises a loudspeaker, a first pickup and an active noise control module, and the loudspeaker is positioned on the air outlet side of the fan; the first pickup is located at the focal point of the hyperboloid; the active noise control module is respectively in communication connection with the loudspeaker and the first pickup. The invention can effectively reduce noise under the condition of meeting the design requirements of ventilation and electromagnetic compatibility of the ventilated type case.
Description
Technical Field
The invention relates to the field of computers, in particular to a noise reduction device for a fan.
Background
The computer noise of the ventilated case mainly comes from the rotation of the fan, and the main sources of the fan noise specifically analyzed are random noise generated by friction vibration of fan blades and air, motor bearing noise and other mechanical noise. With the improvement of the processing precision and the structural form of the motor, the precise high-speed rotation of the bearing can be realized, and the rotation noise of the bearing is extremely low; the noise of the fan blades and air can be improved by optimizing the shape of the fan blades and the design of the air duct, but the improvement method is limited at present. At present, with the increasingly powerful functions of electronic products, the heating power of electronic equipment is increased, so that the rotating speed of a common cooling fan is higher and higher, the tip speed of a fan blade is higher and higher, and the noise is higher and higher.
The ruggedized computer usually requires good ventilation and heat dissipation conditions due to the harsh use environment, so a higher-speed fan is usually required, which causes a non-negligible noise problem and seriously affects the physical and psychological health of operators. At present, the noise reduction design is mainly carried out by selecting a low-noise fan, but the low-noise fan is usually low in air volume and air pressure, the heat dissipation requirement cannot be met necessarily, and the cost is high, so that the noise elimination and sound absorption design is necessary to be carried out from the structural level.
There is therefore a need for a noise reducer for a fan that can effectively reduce noise while meeting the design requirements of ventilation and electromagnetic compatibility of a ventilated enclosure.
Disclosure of Invention
In view of the above problems in the prior art, it is desirable to effectively reduce noise while meeting the design requirements of ventilation and electromagnetic compatibility of a ventilated casing.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
according to the present invention, there is provided a noise reducing device for a fan, comprising an active noise reducing assembly and a passive noise reducing assembly, wherein,
the passive noise reduction assembly is a sound attenuation cover with a hyperboloid, the sound attenuation cover is positioned on the air outlet side of the fan in the fan box, an air cavity is formed between the sound attenuation cover and the fan box, and the focus of the hyperboloid is positioned on the air outlet side of the fan;
the active noise reduction assembly comprises a loudspeaker, a first pickup and an active noise control module, and the loudspeaker is positioned on the air outlet side of the fan; the first pickup is located at the focal point of the hyperboloid; the active noise control module is respectively in communication connection with the loudspeaker and the first pickup.
Furthermore, the silencing cover is provided with micropores.
Further, the active noise reduction assembly further comprises a second pickup located on the air intake side of the fan box.
Furthermore, an air inlet cover plate is arranged at the air inlet of the fan box, and an air outlet cover plate is arranged at the air outlet of the fan box; the air inlet cover plate is provided with an air inlet, and the air outlet cover plate is provided with an air outlet.
Furthermore, the air inlet and the air outlet are respectively two semicircular holes.
Furthermore, an air outlet hole is formed in the middle of the silencing cover and corresponds to an air outlet of the air outlet cover plate.
Further, the air outlet cover plate is provided with a ventilation window on the outer side, and the ventilation window is provided with a gap for ventilation.
Furthermore, a sound insulation lining is arranged between the inner side of the fan box and the fan.
Further, the ventilation window and/or the sound insulation lining are made of foamed metal materials.
Further, the active noise control module is positioned on the outer side of the fan box; the active noise control module is in communication with the second pickup.
Through the technical scheme, the invention can obtain the following beneficial technical effects:
according to the noise reduction device for the fan, the active noise reduction assembly and the passive noise reduction assembly are provided, so that the composite noise reduction of the combination of the passive noise reduction and the active noise reduction of the air resonant cavity can be realized, the effective noise reduction is realized under the condition that the design requirements of ventilation and electromagnetic compatibility of a ventilated type case are met, and meanwhile, the modularization degree is high, the processing cost is low, and the installation is more convenient.
Of course, it is not necessary for any one product in which the invention is practiced to achieve all of the above-described technical effects simultaneously.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a cross-sectional view of one embodiment of a noise reducer for a fan provided in accordance with the present invention;
FIG. 2 is a schematic view of one embodiment of a noise reducer for a fan provided in the present disclosure;
FIG. 3 is a side view of one embodiment of a noise reducer for a fan provided by the present invention.
Detailed Description
As used in the specification and in the claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The following description is of the preferred embodiment for carrying out the invention, and is made for the purpose of illustrating the general principles of the invention and not for the purpose of limiting the scope of the invention. The scope of the present invention is defined by the appended claims.
In one embodiment of the present invention, as shown in fig. 1 to 3, a noise reduction device for a fan is provided, which includes an active noise reduction component and a passive noise reduction component, the passive noise reduction component is a noise reduction cover 5, the noise reduction cover 5 is located at the air outlet side of the fan 4 (i.e. located on the main propagation path of noise) in the fan case 1, specifically, the noise reduction cover 5 may be a thin metal plate material, and the noise reduction cover 5 is fixed on the fan case 1 without contacting with the fan 4. An air cavity is formed between the silencing cover 5 and the fan box 1. The active noise reduction assembly comprises a loudspeaker 6 and a first pickup 7, the first pickup 7 being located on the air outlet side of the fan 4. The muffling enclosure 5 is hyperboloid-shaped (i.e. the cross section conforms to a hyperbolic characteristic) and the focus of the hyperboloid is located on the air outlet side, and the first pickup 7 is located at the focus of the hyperboloid of the muffling enclosure (i.e. the focus corresponding to a part of the hyperboloid). The inner surface of the noise reduction cover 5 can reflect and converge most of sound to the vicinity of a fan rotating shaft (namely, the first pickup 7) so as to facilitate the pickup of scattered noise emitted by the fan 4, so that after the noise at the air outlet side of the fan 4 meets the noise reduction cover 5 during the transmission, part of the noise is reflected and reflected to a hyperboloid focus (namely, the first pickup 7) and is sampled and picked up by the first pickup 7, the active noise control module 11 processes the sampled noise sound wave, controls the loudspeaker to emit sound which is equal to the amplitude of the noise source, has the same frequency and opposite phase, and the sound and the noise are mutually superposed during the transmission process; and another part of the noise is transmitted through the silencing cover 5 and reaches an air cavity between the silencing cover 5 and the fan box 1, the air layer of the air cavity is not equal in thickness, so that the noise can be continuously reflected between the air cavity and resonated with the air, so that the noise energy is consumed, and the noise along the transmission direction can be eliminated by utilizing the air resonance in the air cavity, and the aim of passive noise reduction is fulfilled. Similarly, when noise propagates inside the hyperbolic surface, the noise resonates with air in the air cavity, and noise energy is consumed.
In some embodiments, the muffling enclosure 5 has micro-holes thereon. The micropores are several, preferably evenly distributed. The muffling enclosure 5 with the micropores constitutes a micropore muffling structure (helmholtz resonance chamber) capable of muffling a part of noise waves by air resonance.
In some embodiments, the active noise reduction assembly further comprises a second pickup 8 located on the air intake side of the fan box 1. The first pickup 7 mainly picks up noise partially emitted from the fan 4. The second pickup 8 mainly picks up external noise from the air intake side of the fan 4, which is mainly noise from the inside of the chassis in the case where the fan 4 is a chassis fan of a computer.
In some embodiments, an air inlet cover plate 2 is arranged at the air inlet of the fan box 1, and an air outlet cover plate 3 is arranged at the air outlet of the fan box 1; the air inlet cover plate 2 is provided with an air inlet, and the air outlet cover plate 3 is provided with an air outlet. Preferably, the loudspeaker 6 is fixed on the air outlet cover plate 3, and the second pickup 8 is fixed on the air inlet cover plate 2. The intake cover 2 and the fan case 1 fix and restrain the fan 4, in one example, the fan case 1 or a fixing protrusion extending from the fan case 1 fixes the fan 4 radially in a suitable fixing manner, and the intake cover 2 or a fixing protrusion extending from the intake cover 2 fixes the fan 4 axially in a suitable fixing manner, which may preferably adopt a fastener, such as an adhesive, a screw, welding, etc. Fan box 1 and air inlet apron 2, the cooperation of air-out apron 3 are sealed fan 4 in fan box 1 completely, form the structure of ventilating around only, also are the main passageway that sound was propagated and was controlled.
In some embodiments, the air inlet and the air outlet are two semicircular holes respectively. Alternatively, the air inlet and the air outlet can be any number of circular holes, semicircular holes, square holes and the like.
In some embodiments, the muffling enclosure 5 has an air outlet in the middle, and the air outlet corresponds to the air outlet of the air outlet cover plate 3. Preferably, an air outlet hole in the middle of the muffling cover 5, an air inlet on the air inlet cover plate 2 and an air outlet on the air outlet cover plate 3 are positioned on the same axis. If the air outlet hole, the air inlet and the air outlet are composed of a plurality of holes or gaps, the axis is limited by the central line of the combination composed of the holes or the gaps.
In some embodiments, the outer side of the air outlet cover plate 3 is provided with a ventilation window 9, and the ventilation window 9 is provided with a gap for ventilation, so as to achieve the purposes of ventilation, noise reduction and electromagnetic compatibility design. Set up ventilation window 9 and can prevent that the noise from propagating (for example propagating to quick-witted case) through air outlet department structure (for example air-out apron 3), both can the fixed fan module of switching, reach again with quick-witted case sound insulation's purpose, also satisfy ventilation and electromagnetic compatibility's demand.
In some embodiments, a sound insulating lining 10 is provided between the inside of the fan case 1 and the fan 4. The provision of sound insulating liner 10 acoustically insulates fan 4 from fan case 1, preventing fan noise from propagating through fan case 1, while defining the main propagation direction of the noise to define a noise reduction processing path. In one example, the sound insulation lining 10 may be filled on the inner side wall of the fan case 1, specifically, may be filled in all the portions except the air inlet cover plate 2 and the air outlet cover plate 3, and further may be filled in all the portions except the air inlet and the air outlet. The main propagation path of the noise is thus defined as air inlet (if external noise is present) -fan-muffling enclosure 5 (air chamber) -air outlet, to facilitate the noise reduction process.
In some embodiments, the ventilation window 9 and/or the sound insulating lining 10 are foamed metal materials. Alternatively, sound insulating liner 10 may be another high acoustic resistance material, such as acoustic rubber or a foam material.
In some embodiments, the active noise reduction assembly further comprises an Active Noise Control Module (ANCM)11 disposed outside the fan case 1; the active noise control module 11 is respectively connected with the loudspeaker 6, the first pickup 7 and the second pickup 8 in a communication way. The active noise control module 11 may be packaged in the same module with the fan power supply module and the rotation speed control chip. The second pickup device 8 collects the air inlet noise and other source noise as reference noise and transmits the reference noise into the active noise control module 11, at the moment, the first pickup device 7 at the air outlet of the fan 4 collects the noise at the air outlet of the fan 4 and also transmits the reference noise into the active noise control module 11, the active noise control module 11 is subjected to modulation analysis and calculates propagation delay and sends out a control signal to control the loudspeaker 6 to send out the sound which is equal to the amplitude of the noise source, the frequency is the same, the phases are opposite, the sound and the frequency are mutually superposed in the propagation process, and the purposes of offsetting and reducing the noise are achieved due to the opposite amplitudes, so that the active noise. In the active noise reduction method, the noise of the fan and the sound which is emitted by the active control and has equal amplitude and opposite phase are superposed and offset in a hyperboloid space through a feedforward-feedback-control principle, so that the noise is actively eliminated.
The noise reduction device for the fan provided by the invention utilizes the noise reduction cover 5 with the double-curved-surface structure to construct the air resonant cavity for passive noise reduction, and is combined with an active noise reduction (ANC) technology, wherein high-frequency noise is mainly eliminated through passive noise reduction, and low-frequency noise is mainly eliminated through active noise reduction. Moreover, the noise reduction device can be used for a ventilated case.
The noise reduction device for the fan provided by the invention has the following beneficial effects:
(1) the noise reduction cover 5 with a hyperboloid structure is arranged, so that effective convergence control of noise is realized, and signal acquisition is facilitated;
(2) air resonance is realized by utilizing an air cavity between the sound-absorbing cover 5 with a hyperboloid structure and the fan box and utilizing the Helmholtz principle, so that noise is eliminated;
(3) the passive noise reduction and the active noise reduction are reasonably combined, and the combined and wide-frequency-band noise reduction is realized on the premise of ensuring the ventilation and heat dissipation requirements;
(4) the active noise control module is organically combined with the fan and the noise reduction structure, so that the modular and compact design is realized.
The foregoing are exemplary embodiments of the present disclosure, but it should be noted that, although elements of the present disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated, without departing from the scope of the present disclosure as defined in the claims. It should be understood that, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly supports the exception. It should also be understood that "and/or" as used herein is meant to include any and all possible combinations of one or more of the associated listed items.
The numbers of the embodiments disclosed in the embodiments of the present invention are merely for description, and do not represent the merits of the embodiments.
Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, of embodiments of the invention is limited to these examples; within the idea of an embodiment of the invention, also technical features in the above embodiment or in different embodiments may be combined and there are many other variations of the different aspects of an embodiment of the invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, substitutions, improvements, and the like that may be made without departing from the spirit and principles of the embodiments of the present invention are intended to be included within the scope of the embodiments of the present invention.
Claims (11)
1. A noise reducing device for a fan, characterized by: comprises an active noise reduction component and a passive noise reduction component, wherein,
the passive noise reduction assembly is a sound attenuation cover with a hyperboloid, the sound attenuation cover is positioned on the air outlet side of the fan in the fan box, an air cavity is formed between the sound attenuation cover and the fan box, and the focus of the hyperboloid is positioned on the air outlet side of the fan;
the active noise reduction assembly comprises a loudspeaker, a first pickup and an active noise control module, and the loudspeaker is positioned on the air outlet side of the fan; the first pickup is located at a focal point of the hyperboloid; the active noise control module is respectively in communication connection with the loudspeaker and the first pickup.
2. The noise reduction device according to claim 1, characterized in that:
the silencing cover is provided with micropores.
3. The noise reduction device according to claim 1, characterized in that:
the active noise reduction assembly further comprises a second pickup located on the air intake side of the fan box.
4. The noise reduction device according to claim 1, characterized in that:
the air inlet position of the fan box is provided with an air inlet cover plate, and the air outlet position of the fan box is provided with an air outlet cover plate;
the air inlet cover plate is provided with an air inlet, and the air outlet cover plate is provided with an air outlet.
5. The noise reduction device according to claim 4, wherein:
the air inlet and the air outlet respectively comprise two semicircular holes.
6. The noise reduction device according to claim 4, wherein:
the middle of the silencing cover is provided with an air outlet hole, and the air outlet hole corresponds to the air outlet of the air outlet cover plate.
7. The noise reduction device according to claim 4, wherein:
the air outlet cover plate is provided with a ventilation window on the outer side, and a gap for ventilation is formed in the ventilation window.
8. The noise reduction device according to claim 1, characterized in that:
and a sound insulation lining is arranged between the inner side of the fan box and the fan.
9. The noise reduction device according to claim 7, wherein:
the ventilation window is made of a foaming metal material.
10. The noise reduction device according to claim 8, wherein:
the sound insulation lining is made of foamed metal materials.
11. The noise reduction device according to claim 3, characterized in that:
the active noise control module is positioned on the outer side of the fan box;
the active noise control module is in communication with the second pickup.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711203585.7A CN107725487B (en) | 2017-11-27 | 2017-11-27 | Noise reduction device for fan |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201711203585.7A CN107725487B (en) | 2017-11-27 | 2017-11-27 | Noise reduction device for fan |
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| CN107725487A CN107725487A (en) | 2018-02-23 |
| CN107725487B true CN107725487B (en) | 2020-01-14 |
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| CN110735803A (en) * | 2018-07-18 | 2020-01-31 | 讯凯国际股份有限公司 | Fan shell with foaming metal structure and fan with same |
| US20230392822A1 (en) * | 2022-06-03 | 2023-12-07 | International Business Machines Corporation | Acoustic dampening air moving device housing |
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| CN105065308A (en) * | 2015-08-28 | 2015-11-18 | 苏州清听声学科技有限公司 | Active noise reduction exhaust fan and line-spectrum noise active control method thereof |
| CN105298933A (en) * | 2015-09-11 | 2016-02-03 | 中国船舶重工集团公司第七0九研究所 | Active noise control device for axial fan |
| CN105298934A (en) * | 2015-10-30 | 2016-02-03 | 山东超越数控电子有限公司 | Device for achieving noise reduction of fan |
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2017
- 2017-11-27 CN CN201711203585.7A patent/CN107725487B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH04265500A (en) * | 1991-02-21 | 1992-09-21 | Matsushita Electric Ind Co Ltd | Blower |
| CN102536917A (en) * | 2011-07-19 | 2012-07-04 | 平安电气股份有限公司 | Internal conical barrel muffler for mining fan |
| CN203286197U (en) * | 2013-05-17 | 2013-11-13 | 中国科学院声学研究所 | Active-passive composite silencer for ventilation pipeline |
| CN105065308A (en) * | 2015-08-28 | 2015-11-18 | 苏州清听声学科技有限公司 | Active noise reduction exhaust fan and line-spectrum noise active control method thereof |
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