High rotation speed, low noise, small air duct structure

Abstract

To provide a small-sized air duct structure with high rotation speed and low noise, which can effectively rectify airflow, reduce the generation of turbulence, reduce wind resistance and energy loss, thereby effectively improving the blowing wind speed and blowing distance, and reducing operating noise. [Solution] A high-speed, low-noise, compact air duct structure includes a motor frame with an accommodation cavity (101), an air duct housing, a fan, multiple blades (40), and a wind net. An air duct (201) is provided within the air duct housing. The fan includes a motor and a rotating drum (32). Each blade is inclined such that the plane on which one edge exists forms an angle of 10° to 15° with the cross section of the rotating drum. The wind net includes a fixed ring (51) and four to six guide vane groups. Each guide vane group includes one high guide vane (52) and two low guide vanes (53). The high guide vane is higher than the low guide vanes on the side closer to the first end, and both are inclined in a direction away from the second end from the end closest to the fixed ring to the end farthest from the fixed ring, thereby forming an angle of 10° to 15° with the cross section of the rotating drum.

Description

[Technical Field]

[0001] The present invention relates to the technical field of fans, and more particularly to a high-speed, low-noise, small-sized air duct structure. [Background technology]

[0002] Current designs for micro air duct systems, such as portable seat fans and handheld fans, increasingly use high-speed motors (e.g., 13,000 rpm), but the resulting noise and airflow efficiency issues are becoming increasingly prominent. Conventional air duct structures typically employ silencer structures or silicone seals to reduce noise, which not only increase the system's volume and weight but also increase assembly complexity. Especially in applications requiring miniaturization and weight reduction, these additional structures often fail to meet actual needs. Furthermore, typical oblique windscreen designs primarily use linear guide vanes with equal heights, which cannot precisely control the airflow direction, resulting in high turbulence intensity, energy loss, unstable wind speeds, and high noise (typically ≥ 65 dB when operating at 13,000 rpm).

[0003] In view of the above, there is a need to provide a high rotation speed, low noise, and small size air duct structure to overcome the above deficiencies. Summary of the Invention [Problem to be solved by the invention]

[0004] The purpose of this invention is to improve the problems of existing micro air ducts, such as unstable wind speed and high noise, and to provide a high-speed, low-noise, small-sized air duct structure that aims to significantly reduce system noise and improve outlet wind speed and airflow uniformity. [Means for solving the problem]

[0005] In order to achieve the above object, the present invention a motor frame having an accommodation cavity, wherein positions on the motor frame that form openings on both sides of the accommodation cavity are defined as a first end and a second end, respectively; an air duct housing having an air duct provided therein, one end of which is fixed to the second end to connect the air duct to the accommodating cavity, and the other end of which serves as an outlet; a fan provided within the accommodating cavity and including a motor and a rotating drum; a plurality of blades evenly fixed to the outer surface of the rotating drum, each blade having a plane on which an edge portion closer to the second end exists that forms an angle of 10° to 15° with the cross section of the rotating drum, and each blade is inclined in a direction away from the second end from the end closer to the rotating drum to the end farther from the rotating drum; a fixed ring provided near the second end of the motor frame; and a wind net including four to six guide vane groups connected between the fixed ring and the inner wall of the accommodating cavity, each guide vane group including one high guide vane and two low guide vanes, the high guide vane and the low guide vane being flush with each other on the side closer to the second end and both being perpendicular to the surface of the fixed ring, and the high guide vane being higher than the low guide vane on the side closer to the first end and both being inclined in a direction away from the second end from the end closer to the fixed ring to the end farther from the fixed ring, thereby both forming an angle of 10° to 15° with the cross section of the rotating drum.

[0006] In one preferred embodiment, the high guide vanes and the low guide vanes are uniformly distributed and both are inclined at a predetermined angle along the same direction relative to the radial direction of the fixed ring.

[0007] In one preferred embodiment, the side of the high guide vane closer to the first end is curved into an arcuate surface, and the bending direction is opposite to the rotation direction of the blade.

[0008] In one preferred embodiment, the number of guide vane groups is five.

[0009] In one preferred embodiment, the number of the blades is 7 to 11.

[0010] In one preferred embodiment, the cross-sectional area of ​​the air duct decreases with increasing distance from the motor frame, and the diameter ratio of the end of the air duct closer to the motor frame to the end farther from the motor frame is 1:0.70 to 1:0.80.

[0011] In one preferred embodiment, an air duct nozzle extending into the air duct is provided on the side of the fixed ring closer to the air duct housing, and a fixed drum is provided on the side away from the air duct housing, with a first bearing and a second bearing provided within the fixed drum and spaced apart along the axial direction, a drive shaft is provided within the rotating drum, and the drive shaft is inserted into and fixed within the first bearing and the second bearing, a stator of the motor is fixed to the outer wall of the fixed drum, and a rotor of the motor is provided on the inner wall of the rotating drum.

[0012] In one preferred embodiment, the motor frame has a rounded chamfer on the side located at the first end.

[0013] In one preferred embodiment, the air duct housing further includes a wind direction adjustment ring, wherein the inner wall of the end of the air duct housing remote from the motor frame is provided with an annular groove that is recessed inward and partially spherical, the outer surface of the wind direction adjustment ring is protruding outward to fit into the annular groove, and rotation shafts are provided on both sides opposite the wind direction adjustment ring, and the end of the air duct housing remote from the motor frame is provided with rotation grooves that fit the rotation shafts, and the rotation shafts are inserted into the rotation grooves so that the wind direction adjustment ring can rotate within the annular groove around the straight line on which the two rotation shafts exist.

[0014] In one preferred embodiment, two adjacent blades are projected in the axial direction of the rotating drum so as to partially overlap each other. [Effects of the Invention]

[0015] The high-speed, low-noise, small-sized air duct structure provided by this invention has blade edges inclined at 10° to 15° relative to the axial direction of the rotating drum, and one group of high guide vanes and two groups of low guide vanes are installed within the windscreen. Furthermore, the axial edge on one side of each guide vane is inclined at 10° to 15° relative to the axial direction of the rotating drum. This asymmetric and uneven guide vane arrangement effectively straightens the airflow, reduces turbulence, and reduces wind resistance and energy loss, thereby effectively improving the blowing wind speed and blowing distance and reducing operating noise. [Brief explanation of the drawings]

[0016] In order to more clearly explain the technical solutions of the embodiments of the present invention, the following will briefly describe the drawings necessary for the embodiments. It should be understood that the following drawings only illustrate some embodiments of the present invention and should not be considered as limiting the scope thereof. Those skilled in the art can obtain other related drawings based on these drawings without any creative efforts. [Figure 1] 1 is a perspective view of a high-speed, low-noise, small-sized air duct structure provided by the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the high-speed, low-noise, small-sized air duct structure shown in FIG. 1. [Figure 3] FIG. 2 is a vertical cross-sectional view of the high-speed, low-noise, small-sized air duct structure shown in FIG. 1. [Figure 4] This is a schematic diagram of a high-speed, low-noise, small-sized air duct structure when the blades are on the rotating drum. [Figure 5] FIG. 5 is a top view of the blade shown in FIG. 4 when it is on the rotating drum. [Figure 6] This is a schematic diagram of a wind net with a high rotation speed, low noise, and small air duct structure. [Figure 7] 7 is a view of the wind net in the motor frame shown in FIG. 6 taken along the arrow AA. [Figure 8] FIG. 2 is a vertical cross-sectional perspective view of the wind net. DETAILED DESCRIPTION OF THE INVENTION

[0017] In order to make the objectives, technical solutions and beneficial technical effects of the present invention more clearly understood, the present invention will be described in more detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are for the purpose of illustrating the invention, but are not for the purpose of limiting the invention.

[0018] It should also be understood that the terminology used in the specification of the present invention is for the purpose of describing particular embodiments only, and is not intended to limit the present invention. As used in the specification of the present invention and the claims, the singular forms "a," "one," and "the" are intended to include the plural forms unless the context clearly dictates otherwise.

[0019] It should be further understood that the term "and / or," as used in the specification and appended claims, means and includes any and all possible combinations of one or more of the associated listed items.

[0020] In one embodiment, a high rotation speed, low noise, small air duct structure 100 is provided that can be applied to micro air duct systems such as portable seat fans and handheld fans, which has the advantages of high rotation speed, long blowing distance, and low operating noise.

[0021] As shown in FIGS. 1 to 8, the high rotation speed, low noise, compact air duct structure 100 includes a motor frame 10 having an accommodation cavity 101, an air duct housing 20, a fan 30, a plurality of blades 40, and a wind net 50.

[0022] The motor frame 10 is generally cylindrical. The accommodating cavity 101 is coaxially formed inside the motor frame 10 and has a cylindrical shape. Both axial ends of the accommodating cavity 101 penetrate the motor frame 10, forming two openings. To facilitate the description of the positions of each component, the positions on the motor frame 10 that form the openings on both sides of the accommodating cavity 101 are defined as a first end 11 and a second end 12, respectively. The first end 11 is the location of the air inlet. Furthermore, the side of the motor frame 10 located at the first end 11 is chamfered to form a bell-mouth structure 102, which effectively increases the airflow, improving the airflow rate by approximately 1.2 times compared to a structure without the chamfer. It also effectively pre-compresses the airflow and reduces turbulence. Meanwhile, because the diameter of the accommodating cavity 101 remains unchanged, it stabilizes the laminar flow and reduces speed fluctuations.

[0023] An air duct 201 is provided within the air duct housing 20. The air duct 201 is generally conical in shape with a truncated top. One end of the air duct housing 20 is fixed to the second end 12, connecting the air duct 201 to the accommodation cavity 101, and the other end is an air outlet 202. The overall flow direction of the airflow is from the external environment to the first end 11 of the motor frame 10, the second end 12, the air duct 201, the air outlet 202, and back to the external environment.

[0024] Furthermore, the cross-sectional area of ​​the air duct 201 decreases with increasing distance from the motor frame 10, forming a tapered air duct. The diameter ratio of the end of the air duct 201 closest to the motor frame 10 to the end farther from the motor frame 10 is 1:0.70 to 1:0.80, preferably 1:0.75. This tapered air duct accelerates the discharged air to approximately 8 m / s, suppresses airflow separation, and extends the discharge distance. Combined with the bell-mouth structure 102 at the first end 11 of the motor frame 10, this creates a two-stage tapered structure for the entire motor frame 10 and air duct housing 20, synergistically reducing turbulence and lowering measured noise to 53.8 dB (less than the industry average of 60 dB).

[0025] The fan 30 is provided in the accommodating cavity 101 and includes a motor 31 and a rotating drum 32. The motor 31 includes a coil stator 311 and a magnet rotor 312. For example, the coil stator 311 of the motor 31 is fixed inside the accommodating cavity 101, the magnet rotor 312 is provided on the inner wall of the rotating drum 32, a drive shaft 33 is provided inside the rotating drum 32, and the magnet rotor 312 rotates around the drive shaft 33.

[0026] A plurality of blades 40 are uniformly fixed to the outer surface of the rotating drum 32. Conventional blades are usually in the form of a twisted sheet, and the plane of the edge facing the blowing side (the edge line of which may be twisted depending on the blade) is perpendicular to the cross section of the fixed cylindrical surface where the contact line is located (i.e., parallel to the cross section of the fixed cylindrical surface). On the other hand, in this embodiment, the plane of the edge of each blade 40 near the second end 12 forms an angle of 10° to 15° with the cross section of the rotating drum 32, and the blade is inclined in a direction away from the second end 12 from the end closest to the rotating drum 32 to the end farthest from the rotating drum 32. In other words, the upwind side of each blade 40 is shifted inward by 10° to 15° along the axial direction of the rotating drum 32, thereby forming a hypotenuse with an inclination angle of 10° to 15°. This inclination angle may be 10°, 11°, 12°, 13°, 14°, 15°, or other values.

[0027] In this embodiment, the number of blades 40 is 7 to 11, and preferably 9 (the number of blades 40 is usually an odd number). Furthermore, as shown in Fig. 5, two adjacent blades 40 partially overlap when projected in the axial direction of the rotating drum 32, and the partial overlap of the blades 40 can effectively increase the speed of the airflow.

[0028] As shown in FIGS. 2 to 3 and 6 to 8, the windscreen 50 includes a fixed ring 51 provided near the second end 12 of the motor frame 10 and four to six guide vane groups connected between the fixed ring 51 and the inner wall of the accommodating cavity 101. Preferably, the number of guide vane groups is five. Specifically, each guide vane group includes one high guide vane 52 and two low guide vanes 53. On the side closer to the second end 12, the high guide vane 52 and the low guide vane 53 are flush with each other and are both perpendicular to the surface of the fixed ring 51 (i.e., the cylindrical surface of the fixed ring 51). On the side closer to the first end 11, the high guide vane 52 is higher than the low guide vane 53. Both the high guide vane 52 and the low guide vane 53 are inclined in a direction away from the second end 12 from the end closest to the fixed ring 51 to the end farthest from the fixed ring 51, i.e., approaching the second end 12 as they move from the inside to the outside. As a result, both form an angle of 10° to 15° with the cross section of the rotating drum 32, and preferably the inclination angle is 10°. By designing both guide vanes with this inclination angle structure, verification through CFD (Computational Fluid Dynamics) has shown that turbulent energy loss can be reduced by approximately 12%, thereby accelerating the discharge airflow and reducing operating noise.

[0029] The high guide vanes 52 and the low guide vanes 53 are uniformly distributed and both are inclined at a predetermined angle (for example, 10°) along the same direction relative to the radial direction of the fixed ring 51. Furthermore, the high guide vanes 52 are bent into an arcuate surface 521 on the side closer to the first end 11, and the bending direction is opposite to the rotation direction of the blades 40.

[0030] In one embodiment, an air duct nozzle 60 is provided on the side of the fixing ring 51 closer to the air duct housing 20, extending into the air duct 201. The air duct nozzle 60 is generally conical and can redirect the radial airflow to flow axially, avoiding excessive wind resistance, ensuring efficient discharge of the airflow, and directing the airflow along a predetermined path, thereby avoiding energy loss due to airflow collisions and turbulence within the air duct 201.

[0031] A fixed drum 54 is provided on the side of the fixed ring 51 away from the air duct housing 20. A coil stator 311 of the motor 31 may be fixed to the circumferential side of the fixed drum 54. A first bearing 55 and a second bearing 56 are provided in the fixed drum 54 and spaced apart in the axial direction, and a drive shaft 33 is provided in the rotating drum 32. The drive shaft 33 is fixedly secured within the first bearing 55 and the second bearing 56, and one end of the drive shaft 33 may be fixed to the inside of the rotating drum 32 by a rivet connection.

[0032] In one embodiment, as shown in FIG. 2 , the high-speed, low-noise, compact air duct structure 100 further includes a wind direction adjustment ring 70. The inner wall of the air duct housing 20 at the end remote from the motor frame 10 is provided with an inwardly recessed, partially spherical annular groove 203. The outer surface of the wind direction adjustment ring 70 is convex outward to fit into the annular groove 203, allowing the wind direction adjustment ring 70 to slip out of the annular groove 203 along both axial ends. Rotation shafts 71 are provided on both opposite sides of the wind direction adjustment ring 70, and rotation grooves 204 that fit the rotation shafts 71 are formed at the end of the air duct housing 20 remote from the motor frame 10. The rotation shafts 71 are inserted into the rotation grooves 204 so that the wind direction adjustment ring 70 can rotate within the annular groove 203 around the line where the two rotation shafts 71 are located, thereby changing the direction in which the air duct 201 blows outward within a certain range.

[0033] Furthermore, because the principles of fluid dynamics are not yet fully understood, the above-described structure, which was achieved through a fortuitous inspiration and continuous improvement efforts, cannot be accurately explained by detailed mathematical modeling as to why it has the above-described advantages and functions. However, CFD verification and actual sample testing can provide more reliable verification. Below, we will explain the significant advances and substantial features of the improved structure of the present invention compared to the prior art using an illustrative example including specific parameters. Example 1

[0034] (1) Two-stage tapered air duct structure: The bell-mouth structure 102 at the first end 11 of the motor frame 10 has a length of 4.5 mm and a diameter that gradually changes from 42 mm to 40 mm, thereby pre-compressing the airflow and reducing turbulence intensity. The accommodation cavity 101 in the motor frame 10 is cylindrical, with a diameter of 40 mm and a length of 27 mm, to stabilize the laminar flow and reduce speed fluctuations. The air duct 201 in the air duct housing 20 has a diameter that gradually changes from 40 mm to 29.5 mm and a length of 32 mm to accelerate the discharge and suppress airflow separation.

[0035] (2) The motor 31 is a brushless motor, with the following parameters: 18 mm diameter / 20 mm height, copper-based heat dissipation housing, PWM speed control (13,000 rpm ±2%); maximum rotation diameter of the blades 40: 39.3 mm, total of 9 blades (inclination angle of the upwind side is 10°, overall thickness is 0.8 mm, PBT material is used), chip gap 0.35 mm.

[0036] (3) The wind net 50 is provided with five groups of guide vanes, each consisting of two low guide vanes 53 (height 9.5 mm) and one high guide vane 52 (height 12.7 mm, with a radian at the end opposite to that of the blade 40), and the inclination angle of the two guide vanes on the side closer to the first end 11 is set to 10°, and the spacing between adjacent guide vanes is 4.5 mm. Comparative Example:

[0037] There was no inclination angle on the side of the guide vane closer to the first end 11, and all the guide vanes were the same height (i.e., no distinction between high guide vanes 52 and low guide vanes 53), there was no inclination angle on the upwind side of the blade 40 (i.e., conventional structure), and the remaining parameters were the same as in Example 1. The fans manufactured in Example 1 and Comparative Example were subjected to various tests in the same environment (bare motor), and the test results are shown in Table 1 below.

[0038] [Table 1]

[0039] As can be seen from the table above, compared to the existing structure, the improved structure has a faster wind speed at the same blowing distance, i.e., a longer blowing distance, a lower rotation speed, requires less power (from 4.1W in the conventional structure to approximately 3.5W), and generates less noise if the motor operating parameters are the same.

[0040] As described above, the high-speed, low-noise, compact air duct structure 100 provided by the present invention has the edges of the blades 40 inclined 10° to 15° in the axial direction relative to the rotary drum 32, one group of high guide vanes and two groups of low guide vanes arranged within the windscreen 50, and the axial edge on one side of each guide vane is inclined 10° to 15° in the axial direction relative to the rotary drum 32. This asymmetric and uneven guide vane arrangement effectively rectifies the airflow, reduces the generation of turbulence, and reduces wind resistance and energy loss, thereby effectively improving the blowing wind speed and blowing distance and reducing operating noise.

[0041] The present invention is not limited to the details described in the specification and embodiments, and additional advantages and modifications will readily occur to those skilled in the art. Accordingly, without departing from the spirit and scope of the general concept as defined by the appended claims and their equivalents, the present invention is not limited to the specific details, representative apparatus, and illustrative examples shown and described herein. [Explanation of symbols]

[0042] 100 High rotation speed, low noise, small air duct structure 10 Motor Frame 101 Storage Cavity 102 Bellmouth structure 11 1st end 12 2nd end 20 Air duct housing 201 Air Duct 202 Air Outlet 203 Annular groove 204 Rotating groove 30 fans 31 Motor 311 Coil stator 312 Magnet rotor 32 Rotating Drum 33 Drive shaft 40 Feathers 50 Windbreaker Net 51 Fixing ring 52 High guide vane 521 Arc Surface 53 Low guide vane 54 Fixed drum 55 First bearing 56 Second bearing 60 Air Duct Nozzle 70 Wind direction adjustment ring 71 Rotation axis

Claims

1. A high rotation speed, low noise, small air duct structure, a motor frame having an accommodation cavity, wherein positions on the motor frame that form openings on both sides of the accommodation cavity are defined as a first end and a second end, respectively; an air duct housing having an air duct provided therein, one end of which is fixed to the second end to connect the air duct to the accommodating cavity, and the other end of which serves as an outlet; a fan provided within the accommodating cavity and including a motor and a rotating drum; a plurality of blades fixed evenly to the outer surface of the rotary drum, each blade having a plane on which an edge portion closer to the second end exists that forms an angle of 10° to 15° with a cross section of the rotary drum, and each blade being inclined in a direction away from the second end from an end closer to the rotary drum to an end farther from the rotary drum; a fixed ring provided near the second end of the motor frame; and a wind net including four to six guide vane groups connected between the fixed ring and the inner wall of the accommodating cavity, each guide vane group including one high guide vane and two low guide vanes, the high guide vane and the low guide vane being flush with each other on the side closer to the second end and both being perpendicular to the surface of the fixed ring, and the high guide vane being higher than the low guide vane on the side closer to the first end and both being inclined in a direction away from the second end from an end closer to the fixed ring to an end farther from the fixed ring, thereby both forming an angle of 10° to 15° with the cross section of the rotating drum.

2. 2. The high rotation speed, low noise, small-sized air duct structure according to claim 1, wherein the high guide vanes and the low guide vanes are uniformly distributed and both are inclined at a predetermined angle along the same direction relative to the radial direction of the fixed ring.

3. 3. The high rotation speed, low noise, small-sized air duct structure according to claim 2, wherein the side of the high guide vane near the first end is bent into an arcuate surface, and the bending direction is opposite to the rotation direction of the blade.

4. 2. The high rotation speed, low noise, small-sized air duct structure according to claim 1, wherein the number of said guide vane groups is five.

5. 2. The high rotation speed, low noise, small size air duct structure according to claim 1, wherein the number of the blades is 7 to 11.

6. 2. The high-speed, low-noise, compact air duct structure according to claim 1, wherein the cross-sectional area of ​​the air duct decreases with increasing distance from the motor frame, and the diameter ratio of the end of the air duct close to the motor frame to the end of the air duct far from the motor frame is 1:0.70 to 1:0.

80.

7. 2. The high-speed, low-noise, small-sized air duct structure according to claim 1, wherein an air duct nozzle extending into the air duct is provided on the side of the fixed ring closer to the air duct housing, and a fixed drum is provided on the side away from the air duct housing, a first bearing and a second bearing are provided within the fixed drum and spaced apart along the axial direction, a drive shaft is provided within the rotating drum, and the drive shaft is inserted and fixed into the first bearing and the second bearing, a stator of the motor is fixed to the outer wall of the fixed drum, and a rotor of the motor is provided on the inner wall of the rotating drum.

8. 2. The high-speed, low-noise, small-sized air duct structure according to claim 1, wherein a rounded chamfer is formed on the side of the motor frame located at the first end.

9. 2. The high-speed, low-noise, compact air duct structure of claim 1, further comprising an air direction adjustment ring, wherein an inner wall of the air duct housing at an end remote from the motor frame is provided with an annular groove that is recessed inward and partially spherical, an outer surface of the air direction adjustment ring is convex outward to fit into the annular groove, and rotation shafts are provided on both sides opposite the air direction adjustment ring, and a rotation groove that fits the rotation shaft is opened at the end of the air duct housing remote from the motor frame, and the rotation shaft is inserted into the rotation groove so that the air direction adjustment ring can rotate within the annular groove around a straight line on which the two rotation shafts exist.

10. 10. A high-speed, low-noise, small-sized air duct structure according to claim 1, wherein two adjacent blades partially overlap in the axial direction of the rotating drum.

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