Fan for ventilation of automobile seat

Abstract

The utility model belongs to the technical field of fan noise reduction, and discloses a fan for ventilation of an automobile seat, which comprises a motor, the motor drives an impeller to rotate, the fan also comprises an odd number of blades which are arranged around the center of the impeller at non-uniform intervals, and the sizes of the blades are consistent. Compared with a traditional fan, the noise value of the fan can be effectively reduced by adopting unequal-pitch non-uniform distribution, the noise peak value corresponding to the passing frequency of the original blade is scattered and distributed, no particularly remarkable peak value exists, and therefore the decibel value of the highest frequency point is reduced by more than 10 dB.

Description

Technical Field

[0001] The utility model belongs to the technical field of fan noise reduction, and specifically relates to a fan for automobile seat ventilation. Background Technique

[0002] Small axial fans are convenient to use and low in cost, and are widely used in civil and commercial heat dissipation and ventilation. In recent years, due to the rapid development of the computer industry and the improvement of people's living standards, small axial fans with high performance and low noise have become the first choice for heat dissipation. Fan noise can be divided into discrete and broadband noise from the perspective of noise frequency. Noise control generally considers three aspects: one is to start from reducing the noise source; the second is to use mufflers or sound insulators to reduce noise from the noise propagation path; the third is to start from the noise receiver and protect it. The aerodynamic noise generated by the fan blades is much greater than the mechanical noise and electromagnetic noise of the fan. If the air inlet, outlet and blade structure of the fan can be improved, the noise radiated by the fan can be greatly reduced, and there is great research and application prospect in reducing noise from the blade aspect. Therefore, some methods for blade treatment have emerged. The common ones are: perforating the blades to reduce the eddy current noise of the fan, using forward-swept blades to reduce noise, cutting the suction surface of flat blades to reduce noise, using soft trailing edges to reduce noise in the small flow rate area, etc. Among them, using blades with unequal pitch and non-uniform distribution is also a noise reduction measure. The blades of traditional small axial fans are evenly distributed, and in this form, the discrete noise peak generated by the fan is relatively large. By changing the blade distribution form and using non-uniform distribution with unequal pitch, the noise value of the fan can be effectively reduced:

[0003] A fan for automobile seat ventilation is now proposed to solve the above problems. Content of the Utility Model

[0004] To solve the problems raised in the above background technique, the utility model provides a fan for automobile seat ventilation, which solves the problems in the prior art.

[0005] To achieve the above object, the utility model provides the following technical solution: A fan for automobile seat ventilation includes a motor that drives an impeller to rotate, and also includes an odd number of blades with non-uniform spacing around the center of the impeller, and the blade sizes are the same.

[0006] Preferably, there are 17 blades, and the spacing angles of the blades around the center of the impeller are set at specific angles in a clockwise and counterclockwise order in turn, with a starting and ending interval angle of 25.13°.

[0007] Preferably, the diameter of the impeller is 80 - 100 mm; the diameter of the blades around the center of the impeller is 76 - 96 mm.

[0008] Preferably, the arc length of the blade is 32-36 mm.

[0009] Preferably, the starting point to the ending point of the interval angle adopts cosine frequency modulation, and the cosine frequency modulation formula is as follows: Φi′ = Φi + Φi * β * cos(mx), where Φi is the original spacing angle of uniformly spaced blades (number of blades / 360°), Φi′ is the new spacing angle of the i-th blade after modification of non-uniform spacing arrangement, β is the maximum percentage of the change in the spacing angle, n is the number of repetitions of the blade spacing angle to be used, and 0 ≤ x ≤ 2π.

[0010] Preferably, the spacing angles of the blades around the center of the impeller are: 25.13°, 23.06°, 20.02°, 17.58°, 17.01°, 18.62°, 21.57°, 18.62°, 21.57°, 24.31°, 25.41°, 24.30°, 21.57°, 18.62°, 21.57°, 18.62°, 17.01°, 17.58°, 20.02°, 23.06°, 25.13°.

[0011] Preferably, it further includes a fan upper cover and a fan bottom case. The fan upper cover, the impeller, the motor, the PCB board, and the fan bottom case are arranged in sequence to form a fan.

[0012] Preferably, the motor includes a magnetic frame, a stator, a shaft core, bearings, and enameled wires, and is fixed in the fan by a circlip; the shaft core passes through the PCB board and is connected to the bearings, and the motor is electrically connected to the PCB board through the enameled wires; a power interface is provided on the fan bottom case, and an external power supply provides power for the PCB board and the motor; a label is provided at the bottom of the fan bottom case, and the label is pasted on the bottom of the fan bottom case.

[0013] Preferably, the diameter of the impeller is 96 mm; the diameter of the blades around the center of the impeller is 92 mm.

[0014] Preferably, the arc length of the blade is 35.37 mm.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0016] In the present utility model, by providing odd-numbered blades with non-uniformly distributed spacing around the center of the impeller, the distance of each blade is scattered. The non-uniformly distributed spacing of the blades modulates the frequency, and the noise peaks corresponding to the frequency of the original uniformly spaced blades are scattered and distributed, without particularly significant peaks, and the noise of the non-uniformly spaced blades through the frequency is also reduced by more than 10 dB. At this time, the whistling sound that can be heard by the human ear is significantly reduced. When installed on a car seat, it is completely inaudible that there is a whistling sound, and only the sound of the wind exists, effectively improving the human auditory sense. Description of the Drawings

[0017] Figure 1 Schematic diagram of the fan structure of the present utility model;

[0018] Figure 2 Schematic diagram of the non-uniform pitch of the blades of the present utility model;

[0019] Figure 3 Schematic diagram of the blade pitch angle of the present utility model;

[0020] Figure 4 Schematic diagram of the size of the impeller of the present utility model;

[0021] Figure 5 FFT spectrum diagram of the rotation of a conventional uniformly spaced impeller;

[0022] Figure 6 FFT spectrum diagram of the rotation of the non-uniformly spaced impeller of the present utility model.

[0023] In the figure: 1. Fan upper cover; 2. Impeller; 3. Magnetic frame; 4. Shaft core; 5. Enameled wire; 6. Stator; 7. PCB board; 8. Bearing; 9. Fan bottom shell; 10. Spring; 11. Snap ring; 12. Label; 201. Blade. Specific implementation manners

[0024] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0025] As Figures 1 - 4 shown, in Embodiment 1, the present utility model provides a fan for automotive seat ventilation, including a motor, the motor drives the impeller to rotate, and further includes an odd number of blades with non-uniform spacing around the center of the impeller. As shown in the figure, the spacing angle of each blade is different, that is, the spacing angles A≠B≠C≠D....; the blade sizes are the same; there are 17 blades, and the starting points of the spacing angles of the blades around the center of the impeller are sequentially set at specific angles clockwise and counterclockwise, with an interval angle of 25.13° as the starting and ending points.

[0026] The diameter of the impeller is 80 - 100 mm; the diameter of the blades around the center of the impeller is 76 - 96 mm. Preferably, the diameter of the impeller is 96 mm; the diameter of the blades around the center of the impeller is 92 mm.

[0027] The arc length of the blade is 32 - 36 mm; preferably, the arc length of the blade is 35.37 mm. The inner diameter of the blade is 52.1 mm.

[0028] The spacing angle of the blades around the impeller center from the starting point to the ending point of the spacing angle adopts cosine frequency modulation. The cosine frequency modulation formula is as follows: Φi′ = Φi + Φi * β * cos(mx), where Φi is the original spacing angle of the evenly spaced blades (number of blades / 360°), Φi′ is the new spacing angle of the i-th blade after modification of the non-uniform spacing arrangement, β is related to the maximum percentage change in the spacing angle, n is the number of repetitions of the blade spacing angle to be used, generally between n = 2 and n = 11, 0 ≤ x ≤ 2π; through a large number of tests, the variable β related to the maximum percentage change in the spacing angle generally remains in the range of about 0.005 to about 0.05, and n = 9 is optimal.

[0029] The spacing angles of the blades around the impeller center are: 25.13°, 23.06°, 20.02°, 17.58°, 17.01°, 18.62°, 21.57°, 18.62°, 21.57°, 24.31°, 25.41°, 24.30°, 21.57°, 18.62°, 21.57°, 18.62°, 17.01°, 17.58°, 20.02°, 23.06°, 25.13°.

[0030] A fan for automotive seat ventilation includes a motor that drives the impeller to rotate, and also includes an odd number of blades with non-uniform spacing around the impeller center, and the blade sizes are the same; it also includes a fan upper cover and a fan bottom shell. The fan upper cover, impeller, motor, PCB board, and fan bottom shell are arranged in sequence to form a fan. The motor includes a magnetic frame, a stator, a shaft core, bearings, and enameled wire, and is fixed in the fan by a snap ring; the shaft core passes through the PCB board and is connected to the bearings, and the motor is electrically connected to the PCB board through the enameled wire; a power interface is provided on the fan bottom shell, and an external power supply provides power for the PCB board and the motor; a label is provided at the bottom of the fan bottom shell, and the label is pasted on the bottom of the fan bottom shell.

[0031] As Figure 5 shown, the current number of fan blades is 17. When the rotational speed is 4800 rpm, the fan can meet the performance requirements such as the ventilation volume of the automotive seat and the overall chair noise.

[0032] The impeller rotational speed calculation formula: N = 60 * F / P, where N represents the impeller rotational speed, the unit is RPM; F represents the rotational frequency of the impeller, the unit is Hz; P represents the number of impeller blades;

[0033] According to the above formula, when the rotational speed is about 4800 rpm, the impeller rotation frequency is about 1360 Hz, and the human ear is most sensitive to sounds in the range of about 1000 Hz to 4000 Hz;

[0034] As Figure 5 shown, there will be an obvious noise peak near 1360 Hz. At this time, the human ear can clearly hear a high-frequency whistling sound, and this whistling sound is the multiple frequency of the number of blades;

[0035] As Figure 2 shown, by adjusting the angle of each blade of the impeller to make it an unequal pitch blade, the blade angles start from angle A and are 24.31°, 21.57°, 18.62°, 17.01°, 17.58°, 20.02°, 23.06°, 25.13°, 25.13°, 23.06°, 20.02°, 17.58°, 17.01°, 18.62°, 21.57°, 24.31° and 25.41° respectively.

[0036] As Figure 6 shown, the blades form uneven spacing around the central hub or shaft of the impeller, and the normal heat dissipation or other functions of the fan are not affected. The multiple frequency of the number of blades maintains a certain fluctuation over time, but reduces the high-frequency whistling sound emitted from the fan.

[0037] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0038] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fan for automotive seat ventilation, comprising a motor that drives an impeller to rotate, characterized in that: It also includes odd-numbered blades with non-uniformly distributed spacings around the center of the impeller. The starting points of the spacing angles of the blades around the impeller center are sequentially set at specific angles in a clockwise and then counterclockwise manner, with the starting and ending points of the spacing angle being 25.13°.

2. The fan according to claim 1, wherein: The number of the blades is 17.

3. The fan according to claim 1, characterized in that: The diameter of the impeller is 80 - 100 mm; the diameter of the blades around the impeller center is 76 - 96 mm.

4. The fan according to claim 1, wherein: The arc length of the blades is 32 - 36 mm.

5. The fan according to any one of claims 2 to 4, characterized in that: The starting point to the ending point of the spacing angle adopts cosine frequency modulation, and the cosine frequency modulation formula is as follows: Φi′ = Φi + Φi * β * cos(mx), where Φi is the original spacing angle of uniformly spaced blades (number of blades / 360°), Φi′ is the new spacing angle of the i-th blade after modification of non-uniform spacing arrangement, β is the maximum percentage of the change in the spacing angle, n is the number of repetitions of the blade spacing angles to be used, and 0 ≤ x ≤ 2π.

6. The fan according to claim 5, characterized in that: The spacing angles of the blades around the impeller center are: 25.13°, 23.06°, 20.02°, 17.58°, 17.01°, 18.62°, 21.57°, 18.62°, 21.57°, 24.31°, 25.41°, 24.30°, 21.57°, 18.62°, 21.57°, 18.62°, 17.01°, 17.58°, 20.02°, 23.06°, 25.13°.

7. The fan according to claim 1, characterized in that: It also includes a fan upper cover and a fan bottom case. The fan upper cover, impeller, motor, PCB board, and fan bottom case are sequentially arranged to form a fan.

8. The fan according to claim 7, characterized in that: The motor includes a magnetic frame, a stator, a shaft core, bearings, and enameled wire, and is fixed in the fan by a snap ring; the shaft core passes through the PCB board and is connected to the bearings, and the motor is electrically connected to the PCB board through the enameled wire; a power interface is provided on the fan bottom case, and an external power supply provides power for the PCB board and the motor; a label is provided at the bottom of the fan bottom case, and the label is pasted at the bottom of the fan bottom case.

9. The fan according to claim 3, characterized in that: The diameter of the impeller is 96 mm; the diameter of the blades around the impeller center is 92 mm.

10. The fan according to claim 4, characterized in that: The arc length of the blades is 35.37 mm.

11. The fan according to claim 1, characterized in that: The sizes of the blades are the same.

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