A self-silencing fan frame

Abstract

This invention discloses a self-silencing fan frame, belonging to the field of fan frame technology. It includes a frame with an air outlet, a central structure at the air outlet, and several ribs of varying heights arranged between the frame and the central structure. The ribs are arranged in a ring around the center of the air outlet, dividing the air outlet into several regions corresponding to the number of ribs. Each rib includes sound-absorbing ribs and supporting ribs arranged between adjacent sound-absorbing ribs. The height of the sound-absorbing ribs decreases or increases sequentially, while the supporting ribs are of uniform height. This solution utilizes the fan frame's own structure for sound absorption, resulting in rapid, simple, and low-cost production. It does not increase the volume or weight of the fan frame, nor does it reduce the air outlet area, ensuring sufficient airflow from the fan.

Description

Technical Field

[0001] This invention belongs to the field of fan frame technology, specifically relating to a self-silencing fan frame. Background Technology

[0002] An electric fan is a device that uses electricity to drive the blades to rotate and generate airflow. The high-speed rotation of the blades produces harmful noise.

[0003] Chinese patent CN101816534A discloses a noise reduction structure for controlling such noise. This structure includes multiple discrete passive silencers in the form of duct silencers arranged in a first group and a second group. The duct silencers have open ends positioned to face the fan, and the silencers in the first group are separated from those in the second group in both the axial and radial directions.

[0004] The aforementioned pipe-based or common honeycomb-shaped noise reduction structures all use long pipe diameters to reduce noise, increasing the size and weight of the fan. They are suitable for large industrial fans or externally mounted fans, but not for cooling fans widely used for cooling computer CPUs, because cooling fans need to be installed inside the computer where space is limited. Reducing the size and weight of cooling fans, and thus reducing the size and weight of the computer, is a trend in the development of electronic products. Pipe-based and honeycomb-shaped noise reduction structures divide the fan exhaust outlet into densely arranged holes, reducing the air volume and making it easy to collect dust. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is: a self-silencing fan frame, the one-piece molded fan frame includes a frame with an air outlet, a frame center structure located at the air outlet, and a plurality of ribs of different heights disposed between the frame and the frame center structure, the plurality of ribs being arranged in a ring around the center of the air outlet as the base point, dividing the air outlet into a plurality of regions consistent with the number of ribs.

[0006] The ribs include sound-absorbing ribs and support ribs disposed between adjacent sound-absorbing ribs. The height of several sound-absorbing ribs decreases or increases sequentially, while the height of several support ribs is consistent.

[0007] Specifically, the height of several of the sound-absorbing ribs decreases or increases proportionally in sequence.

[0008] Specifically, the cross-section of the rib is rectangular.

[0009] Specifically, the rib is a linear straight rod.

[0010] Specifically, the rib does not pass through the base point.

[0011] Specifically, several of the ribs are bent counterclockwise or clockwise, with a consistent degree of curvature.

[0012] Specifically, the central structure of the frame includes a tray for mounting the circuit board and a shaft hole opened in the bottom of the tray, the shaft hole connecting to a fan shaft whose axis passes through the base point.

[0013] Specifically, the fan shaft is connected to X fan blades, and there are Y ribs in total, where X = Y ± 2n + 1, and Y and X are both natural numbers.

[0014] Specifically, one of the support ribs has a groove for routing circuit board traces.

[0015] Specifically, the frame is provided with sloping sidewalls to gradually increase the diameter of the air outlet.

[0016] The technical solution provided by this invention has the following advantages compared with the prior art:

[0017] The fan is equipped with several folded ribs of varying heights. When mid-to-high frequency noise passes through the ribs, it is refracted between the ribs, thus reducing or even eliminating the noise. The fan frame itself is used for noise reduction. The fan frame is integrally molded, making production quick, simple, and low-cost. Compared with existing cooling fans, it does not increase the size and weight of the fan frame, and can still be installed in computers with limited space. It also does not reduce the air outlet area, ensuring the cooling performance of the fan and preventing dust accumulation at the air outlet. Attached Figure Description

[0018] Figure 1 This is an overall structural diagram of the self-silencing fan frame in an embodiment of the present invention;

[0019] Figure 2 This is the NACA airfoil diagram of the sound-absorbing rib in this embodiment of the invention;

[0020] Figure 3 This is a curve diagram of the sound-absorbing ribs in an embodiment of the present invention;

[0021] Figure 4 This is a graph showing the airflow and air pressure curves for noise testing in an embodiment of the present invention.

[0022] The figure shows: 1. Frame; 2. Frame center structure; 21. Tray; 22. Hole; 23. Shaft hole; 3. Silencing device; 31. Silencing rib; 32. Supporting rib; 4. Air outlet; 5. Sloping side wall; 6. Cable trough. Detailed Implementation

[0023] For ease of understanding, the self-silencing fan frame is described below with reference to embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation and positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Example 1

[0027] like Figure 1 As shown, a self-silencing fan frame includes an integrally formed frame 1, a central frame structure 2, and a silencing device 3. A motor is installed inside the frame 1, which drives the fan shaft to rotate. The fan blades connected to the fan shaft rotate accordingly, causing airflow to generate wind. A circular air outlet 4 facing the fan is provided on the front side of the frame 1. The wind generated by the fan blades is discharged from the air outlet 4. The frame 1 is provided with an inclined side wall 5 that gradually increases the diameter of the air outlet 4 from back to front, ensuring that the air outlet 4 has sufficient airflow space.

[0028] A frame center structure 2 is provided at the center of the air outlet 4. The frame center structure 2 includes a tray 21, which is circular. A slot 22 with the same shape as the circuit board is opened in the middle of the tray, and a shaft hole 23 for the fan shaft to be inserted is opened at the bottom of the tray. The PCBA circuit board is installed in the slot 22. The frame 1 and the frame center structure 2 are both centered on the fan shaft. The axis of the fan shaft passes through the center of the air outlet 4, which makes the fan shaft highly balanced when rotating.

[0029] A silencing device 3 is provided between the frame 1 and the central structure 2 of the frame. The silencing device 3 is composed of several ribs. The ribs and the fan blades are arranged around the fan shaft. Each rib is connected to the inner wall of the frame 1 at one end and to the outer wall of the central structure 2 at the other end, dividing the air outlet 4 between the frame 1 and the tray 21 into multiple areas with the same number of ribs. The ribs are linear straight rods or curved rods with rectangular cross-sections that do not pass through the center of the air outlet 4. If they are curved rods, all the ribs need to be bent in the same direction, either counterclockwise or clockwise, with the same degree of curvature.

[0030] The ribs include sound-absorbing ribs 31 and support ribs 32 disposed between adjacent sound-absorbing ribs 31. The height of several sound-absorbing ribs 31 decreases proportionally along the rotation direction of the fan blades to improve the noise reduction effect of the fan frame. All sound-absorbing ribs 31 have the same width and their height is lower than that of the support ribs 32. One of the support ribs 32 has a groove 6 for the circuit board wiring. All support ribs 32 have the same height and width.

[0031] The number of fan blades is X, and the number of ribs is Y, where X = Y ± 2n + 1. Both Y and X are natural numbers, which makes the number of fan blades and the number of ribs inconsistent and conforms to the principle of odd numbers to even numbers, thus avoiding the frequency overlap between ribs and fan blades and the generation of resonance.

[0032] In this embodiment, the number of ribs M1 is 10, including 5 supporting ribs 32 and 5 sound-absorbing ribs 31. The width B1 of each rib is 2mm and the length L1 is 24.6mm.

[0033] The area S of the silencing device 3 01 =M1*B1*L1=10*2mm*24.6mm=492mm2.

[0034] Noise reduction principle: A sound contains sound waves of different frequencies. After the noise passes through the ribs, the different sound waves are refracted between the ribs at different heights until they are weakened or even disappear, thus achieving a filtering function. It has a good noise reduction effect on the mid-to-high frequency range.

[0035] Example 2

[0036] The only difference between this embodiment and Embodiment 1 is that the number of ribs M2 in this embodiment is 11, of which there are 5 supporting ribs 32 and 6 sound-absorbing ribs 31. The width B2 of each rib is 2mm and the length L2 is 24.6mm.

[0037] The area S of the silencing device 3 02 =M2*B2*L2=11*2mm*24.6mm=541.2mm 2 .

[0038] Example 3

[0039] The only difference between this embodiment and Embodiment 1 is that the number of ribs M3 in this embodiment is 12, of which there are 6 supporting ribs 32 and 6 sound-absorbing ribs 31, and the width B3 of each rib is 2mm and the length L3 is 24.6mm.

[0040] The area S of the silencing device 3 03 =M3*B3*L3=12*2mm*24.6mm=590.4mm 2 .

[0041] Comparative Example

[0042] The fan frame in this comparative example is currently used in computer internal cooling fans. The difference from Example 1 is that this comparative example does not have a sound-absorbing rib 31. There are 4 supporting ribs 32 between the frame 1 and the frame center structure 2. Among them, 3 ribs have a width B4 of 4.0mm, 1 rib has a width B5 of 9mm, and the length L4 of each supporting rib 32 is 24.6mm.

[0043] Support ribs 32, total area S 04 =3*B4*L 3+ B5*L3;

[0044] S 04 =3*4mm*24.6mm+9mm*24.6mm=516.6mm 2 .

[0045] The fan outer frame in the above-mentioned Embodiment 1, Embodiment 2, Embodiment 3 and comparative example has an outer dimension of 92mm*92mm*25mm and a thickness of 2mm on one side. Ignoring the increase in the diameter of the air outlet 4 due to the inclined sidewall 5, the diameter L5 of the air outlet 4 is 88mm, and the outer diameter r of the central structure 2 of the frame is 38.8mm.

[0046] It can be seen that the area S of the air outlet 4 q =π(L5 / 2) 2 ;

[0047] Substituting L5 = 88mm into the above formula, we get S q =π(L5 / 2) 2 =6079mm 2 ;

[0048] The central structure of the frame has an area of ​​S. p =π(r / 2) 2 ;

[0049] Substituting r = 38.8 mm into the above formula, we obtain S. p=π(r / 2) 2 =1181mm 2 ;

[0050] The actual air outlet area of ​​the fan frame S = S q -S p -S0.

[0051] Calculations show that the area occupied by the ribs in the second embodiment of the air outlet 4 is slightly larger than that occupied by the ribs in the comparative example. According to the principle of the silencing device 3, the more silencing devices there are, the higher the sound refractive index and the better the silencing effect. The preferred number of ribs is 11, with 5 supporting ribs 32 and 6 silencing ribs. The fan frame has a rib width of 2mm. Based on the number of ribs, to avoid the ribs and fan blades coinciding, the fan frame is preferably assembled with a fan shaft of 8 fan blades.

[0052] The specific steps for designing the sound-absorbing rib 31 are as follows:

[0053] Step 1: Select the NACA airfoil, such as... Figure 2 As shown;

[0054] Step 2: Generate 172 point parameters and input the point parameters into the design table, as shown in Table 1 below;

[0055] Step 3: By adjusting the table parameters, including the outer diameter, inner diameter, inclination angle, mounting angle, and outclination angle of the sound-absorbing rib 31, a curve graph is generated, such as... Figure 3 As shown;

[0056] Step 4: Import the data corresponding to the curve into the 3D software to generate a 3D image of the sound-absorbing rib 31 and perform feature editing.

[0057] Table 1. Data Table of Sound-Absorbing Rib Location Parameters

[0058]

[0059] According to the PQ test standard AMCA210 and the noise test standard ISO10302, motors of the same specifications and models were installed in the fan frames of Example 2 and the comparative example. The motors drove the fan shaft to run at 4500 rpm, and the airflow and air pressure curves were obtained, as shown in the figure. Figure 4 As shown, Figure 4 In Table 2, a represents the fan frame with a noise level of 4500 rpm-45.2 dB in the comparative example, and b represents the fan frame with a noise level of 4500 rpm-42.8 dB in Example 2. The noise data are shown in Table 2 below.

[0060] Table 2 Noise Test Statistics Table

[0061]

[0062] Among them, the noise of three different rotation speeds was tested. In each of the two examples with the same rotation speed, the fan frame noise was 2-3 dBA lower than that of the fan frame in the comparative example, and the noise was significantly improved.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-silencing fan frame, characterized in that, The one-piece molded fan frame includes a frame with an air outlet, a frame center structure located at the air outlet, and several ribs of different heights disposed between the frame and the frame center structure. The several ribs are arranged around the center of the air outlet, dividing the air outlet into several areas with the same number of ribs. The ribs include sound-absorbing ribs and support ribs disposed between adjacent sound-absorbing ribs. The height of several sound-absorbing ribs decreases or increases sequentially, and the height of several support ribs is the same. All sound-absorbing ribs have the same width and are lower than the height of the supporting ribs. All supporting ribs have the same height and width.

2. The self-silencing fan frame as described in claim 1, characterized in that, The height of several of the aforementioned sound-absorbing ribs decreases or increases proportionally in sequence.

3. The self-silencing fan frame as described in claim 1, characterized in that, The cross-section of the rib is rectangular.

4. The self-silencing fan frame as described in claim 3, characterized in that, The ribs are linear straight rods.

5. The self-silencing fan frame as described in claim 4, characterized in that, The ribs do not pass through the base point.

6. The self-silencing fan frame as described in claim 3, characterized in that, Several of the aforementioned ribs are bent counterclockwise or clockwise, with a consistent degree of curvature.

7. The self-silencing fan frame as described in claim 1, characterized in that, The central structure of the frame includes a tray for mounting the circuit board and a shaft hole opened in the bottom of the tray, the shaft hole being connected to a fan shaft whose axis passes through the base point.

8. The self-silencing fan frame as described in claim 7, characterized in that, The fan shaft is connected to X fan blades, and there are Y ribs in total, where X = Y ± 2n + 1, and Y and X are both natural numbers.

9. The self-silencing fan frame as described in claim 7, characterized in that, One of the support ribs has a groove for routing circuit board traces.

10. The self-silencing fan frame as described in claim 1, characterized in that, The frame is provided with sloping sidewalls to gradually increase the diameter of the air outlet.

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