hair dryer

Abstract

The present invention provides a hair dryer. The hair dryer has an output power of 500W-1500W, a wind speed of 40m / s-100m / s, and an air volume of 200cfm-800cfm. The hair dryer comprises: a housing provided with a grip; an axial fan located within the housing; a motor driving the axial fan to generate airflow; and an air duct assembly connected to the housing. The air duct assembly includes at least one air duct section, the end of the at least one air duct section away from the housing being an air outlet end, and the air outlet end of the at least one air duct section being provided with a sawtooth structure, the sawtooth structure extending in the direction of air outlet, and the teeth of the sawtooth structure gradually converging along the direction of air outlet to form a tip portion. The present invention solves the problem of high noise levels in existing hair dryers.

Description

Technical Field

[0001] The present invention relates to the field of electric tools, in particular to a hair dryer. Background Art

[0002] A hair dryer primarily consists of a duct section, a housing, an axial-flow fan housed within the housing, and a motor that drives the fan. The motor rotates the fan, which in turn drives air flow, which is then blown out of the outlet end of the duct section. The axial-flow fan drives air toward the outlet end of the duct section, creating a high vortex volume and generating considerable noise. Summary of the Invention

[0003] The main purpose of the present invention is to provide a hair dryer to solve the problem of high noise of hair dryers in the prior art.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a hair dryer is provided, the output power of the hair dryer is 500W-1500W, the wind speed of the hair dryer is 40m / s-100m / s, and the air volume is 200cfm-800cfm, the hair dryer comprises: a casing, the casing is provided with a grip portion; an axial fan, the axial fan is located in the casing; a motor, the motor drives the axial fan to generate airflow; an air duct assembly, the air duct assembly is connected to the casing, and the air duct assembly includes at least one air duct section, the end of the at least one air duct section away from the casing is an air outlet end, the air outlet end of the at least one air duct section is provided with a serrated structure, the serrated structure extends toward the direction of air outlet, and the teeth of the serrated structure gradually shrink along the direction of air outlet to form a tip portion.

[0005] Furthermore, the sawtooth structure has a plurality of teeth, and the plurality of teeth are sequentially arranged along the circumference of the air duct section to form a ring structure.

[0006] Furthermore, the teeth are of a pointed type, or the sawtooth structure is of a sinusoidal type.

[0007] Furthermore, the thickness of the teeth of the sawtooth structure gradually decreases along the air outlet direction.

[0008] Furthermore, the teeth of the serrated structure have an inner side surface of the tooth facing the inside of the tube of the air duct section, and an outer side surface of the tooth facing the outside of the tube of the air duct section. The inner side surface of the tooth and the outer side surface of the tooth are planes, and the angle between the inner side surface of the tooth and the outer side surface of the tooth is 0-15 degrees; or the inner side surface of the tooth is an arc surface, and the arc surface bulges in the direction away from the outer side surface of the tooth.

[0009] Furthermore, a plurality of pits are formed on the inner side surface of the teeth of the sawtooth structure facing the inside of the air duct section, and / or a plurality of pits are formed on the inner wall of the air duct section close to the sawtooth structure.

[0010] Furthermore, the cross-sectional shape of the plurality of pits is circular, the diameter of the plurality of pits is 2-5 mm, and the spacing between the centers of the plurality of pits is 2-10 mm.

[0011] Furthermore, at least one air duct section only includes a blowing pipe, the bottom width of each tooth of the sawtooth structure of the blowing pipe is λ3, the height of each tooth of the sawtooth structure of the blowing pipe is h3,

[0012] Furthermore, at least one air duct section only includes a blowing pipe, the inner diameter of the blowing pipe is 50 mm-100 mm, and the number of teeth of the serrated structure of the blowing pipe is 8-30.

[0013] Furthermore, the air duct assembly includes multiple air duct sections, and the inner diameters of at least two adjacent air duct sections are different, and the inner diameter of the air duct section close to the air outlet side is larger than the inner diameter of the air duct section close to the air inlet side.

[0014] Furthermore, the air duct assembly includes two air duct sections, which are blowing pipes; a siphon pipe, which is connected to the blowing pipe, and the inner diameter of the siphon pipe is larger than the inner diameter of the blowing pipe, so as to form a siphon air inlet gap between the air inlet end of the siphon pipe and the air outlet end of the blowing pipe; the hair dryer has an air volume mode that increases the airflow through the siphon pipe and blows the air out from the siphon pipe, and a wind speed mode that blows the air directly out from the blowing pipe.

[0015] Furthermore, when the hair dryer is in wind speed mode, the wind speed is 50m / s-90m / s, the Mach number is 0.15-0.27, and the sawtooth structure is used to reduce the shrill noise of the hair dryer by 1.8db-2.1db.

[0016] Furthermore, when the hair dryer is in air volume mode, the wind speed is 40m / s-70m / s, the Mach number is 0.1-0.2, and the sawtooth structure is used to reduce the shrill noise of the hair dryer by 1.5db-1.8db.

[0017] Furthermore, the air outlet end of the blowing pipe is provided with a serrated structure, and / or the air outlet end of the siphon pipe is provided with a serrated structure.

[0018] Furthermore, the bottom width of each tooth of the sawtooth structure of the siphon tube is λ1, and the height of each tooth of the sawtooth structure of the siphon tube is h1. Alternatively, the inner diameter of the blowing pipe is 50 mm to 100 mm, and the number of teeth of the serrated structure of the blowing pipe is 8 to 30.

[0019] Furthermore, the bottom width of each tooth of the sawtooth structure of the blowing pipe is λ2, and the height of each tooth of the sawtooth structure of the blowing pipe is h2. Alternatively, the inner diameter of the siphon tube is 50-100 mm, and the number of teeth of the serrated structure of the siphon tube is 12-36.

[0020] Furthermore, both the air outlet end of the blowing pipe and the air outlet end of the siphon pipe are provided with a serrated structure, and the ratio of the number of teeth of the serrated structure of the blowing pipe to the number of teeth of the serrated structure of the siphon pipe is 0.3-1.2.

[0021] Furthermore, the material of the air duct section is any one of PP, PC, ABS, and nylon.

[0022] Using the technical solution of the present invention, a motor drives the axial fan to rotate, generating airflow that flows into the branch section. The end of the air duct section away from the housing serves as the outlet. The outlet end of at least one section of the air duct is provided with a serrated structure. The serrated structure extends in the direction of the airflow, with the teeth of the serrated structure gradually converging to form a pointed end in the direction of the airflow. This serrated structure breaks up large vortices and reduces noise, achieving the goal of reducing noise and achieving silent operation of the hair dryer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 A schematic diagram showing a first embodiment of the air duct assembly of the present invention; and

[0025] Figure 2 Shown Figure 1 A schematic diagram of the internal structure of

[0026] Figure 3 Shown Figure 2 An enlarged view of position A;

[0027] Figure 4 Shown Figure 2 An enlarged view of position B;

[0028] Figure 5 A schematic diagram showing a siphon tube provided with a serrated structure but a blowpipe not provided with a serrated structure;

[0029] Figure 6 A schematic diagram showing a blowpipe provided with a sawtooth structure but a siphon pipe not provided with a sawtooth structure;

[0030] Figure 7 Shown Figure 1 Schematic diagram of adjusting to wind speed mode;

[0031] Figure 8 Shown Figure 1 Schematic diagram of the change in thickness of the teeth of the first sawtooth structure and the second sawtooth structure;

[0032] Figure 9 Shown Figure 1 Schematic diagram of the change in thickness of the teeth of the first sawtooth structure and the second sawtooth structure;

[0033] Figure 10 Shown Figure 1 Schematic diagram of noise reduction curve of the duct assembly;

[0034] Figure 11 Shows the internal structure of the hair dryer;

[0035] Figure 12 A schematic diagram showing another embodiment of the air duct assembly of the present invention is shown;

[0036] The above drawings include the following reference numerals:

[0037] 10. Duct section; 11. Siphon tube; 111. First serrated structure; 112. Concave pit; 12. Blowing pipe; 121. Second serrated structure; 20. Connecting sleeve; 30. Support plate; 40. Casing; 41. Grip; 50. Axial fan; 60. Motor. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0040] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity direction; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above directional words are not used to limit the present invention.

[0041] In order to solve the problem of high noise of hair dryers in the prior art, the present invention provides a hair dryer.

[0042] There are three main types of hair dryers on the market: handheld hair dryers for drying hair, garden hair dryers for garden cleaning, and blowers for industrial use. Specifically, handheld hair dryers are mainly used for users to dry their hair. Their power is generally 50-200w, the wind speed is 15-50m / s, and the air volume is 10-30cfm. They need to be small in size, so the inner diameter of their air duct is often 28-60mm. Garden hair dryers are actually cleaning tools. Users need to hold the garden hair dryer to collect fallen leaves and other debris on the ground. There are certain requirements for their handheld weight and blowing performance. Their power is 500W-1500W, and the wind speed is The speed is 40-100m / s, the air volume is 200-800cfm, and the duct diameter is 45-120mm to match the user's needs for both handheld and performance. For blowers for industrial use, they do not need to be handheld, but only need to be fixed in a certain place to directly perform blowing operations. They often pursue high performance. The power of industrial blowers is generally around 1000-5000W, the wind speed is 5-40m / s, and the air volume is generally large. The inner diameter of the duct is less than 1m, and there are also those greater than 1m and up to 2m. It can be seen that the performance of these three hair dryers is quite different. Although they are all used for blowing air, their structures are completely different, and the design ideas during design and development are completely different. This application only makes innovative designs for garden hair dryers.

[0043] like Figure 11 As shown, the hair dryer includes a housing 40, an axial flow fan 50, a motor 60, and an air duct assembly. The housing 40 is provided with a handle 41 and has an air inlet and an air outlet. The axial flow fan 50 is located within the housing 40. The motor 60 drives the axial flow fan 50 to generate airflow. The air duct assembly is connected to the air outlet of the housing 40 and includes at least one air duct segment 10. The end of the at least one air duct segment 10 away from the housing 40 is an air outlet. The airflow generated by the axial flow fan enters the air inlet of the housing, blows into the air duct assembly through the air outlet, and then blows out from the air outlet end of the air duct assembly.

[0044] During use, the hair dryer generates a lot of noise due to the presence of vortices in the airflow. The reasons for this can be traced back to several main stages: First, the axial fan 50 rotates, driving the air flow and generating airflow. At this point, the gas is accelerated from a static state, and vortices are generated in the process of changing from static pressure to dynamic pressure. Second, as the airflow passes through the axial fan 50, the blades of the axial fan 50 cut the airflow, also generating vortices during the cutting process. Third, the axial fan includes a hub and blades, and the airflow initially blows out is annular. This change from annular to circular creates turbulence, which in turn generates vortices. Vortices are continuously generated throughout the entire airflow path, and the larger the vortex, the greater the noise.

[0045] The present invention provides a sawtooth structure at the outlet end of at least one air duct section 10 (see Figure 1 and Figure 12 The sawtooth structure extends in the direction of airflow, and the teeth taper to form a pointed end. This breaks up the large vortex in the air duct, reducing noise and achieving quiet operation while having little effect on wind speed and force.

[0046] The sawtooth structure can be either pointed or sinusoidal. The sinusoidal sawtooth structure has a smoother sawtooth curve, which can mitigate the interaction between the airflow and the sawtooth to a certain extent, resulting in better noise reduction. Considering that the tip of the sawtooth structure may wear during use, the top of the tip has a flat cut surface. This flat cut surface can reduce stress concentration at the tooth end, extend service life, and prevent scratches on the operator during use.

[0047] In addition, the thickness of the teeth of the sawtooth structure gradually decreases along the direction of the air outlet. Figure 8 As shown, the teeth of the sawtooth structure have an inner side of the teeth facing the inside of the air duct section 10, and an outer side of the teeth facing the outside of the air duct section 10. The inner side and the outer side of the teeth are planes, and the angle between the inner side and the outer side of the teeth is r, and r is 0-15 degrees. The thickness of the teeth gradually decreases in the direction of the wind, which makes the sawtooth thinner and sharper in the direction of the wind, which has a better breaking effect on large vortices. When r is 15 degrees, the sawtooth has both a certain strength and a good breaking effect. In another embodiment, as Figure 9 As shown, the inner side of the tooth is an arc surface, which bulges in the direction away from the outer side of the tooth. This arrangement can significantly reduce the stress of the first sawtooth structure 111 and the second sawtooth structure 121, making them less likely to be damaged during a fall.

[0048] like Figures 1 to 4 As shown, multiple dimples 112 are formed on the inner side of the teeth of the sawtooth structure facing the interior of the air duct section 10. Multiple dimples 112 are also formed on the inner wall of the air duct section 10 near the sawtooth structure. As air flows through the siphon tube 11, it is divided into a boundary layer close to the inner tube wall and a vortex layer connected to the boundary layer. A pressure difference exists between the vortex layer and the boundary layer. The dimples 112 structure allows the boundary layer to extend into the dimples 112 structure, expanding the area of the boundary layer. This reduces the pressure difference between the boundary layer and the vortex layer, thereby reducing noise.

[0049] The cross-section of the plurality of dimples 112 is circular, with a diameter of 2-5 mm and a spacing of 2-10 mm between the centers of the dimples 112. Specifically, the diameter of the dimples 112 is 3 mm, and the spacing between the centers of the dimples 112 is 5 mm. The circular dimples 112 are easy to manufacture and, given the same circumference, have the largest area, maximizing the area of the boundary layer, thereby reducing the pressure difference between the boundary layer and the turbulent layer and lowering noise.

[0050] The air duct assembly includes a blow pipe 12, and a serrated structure is provided at the air outlet end of the blow pipe 12. With respect to the setting of the serrated structure at the end of the blow pipe 12, it is necessary to consider the possibility of the air pipe falling. During the use of the hair dryer, the user holds it through the grip 41, and the air outlet end faces the ground to perform a blowing operation. If the hand is released, the air outlet end will first come into contact with the ground. Therefore, the air outlet end needs to have a certain strength so as not to be damaged during the fall. When the serrations are provided at the end of the blow pipe, the strength of the serrations must be particularly considered, so the serrations cannot be too sharp. Therefore, the bottom width of each tooth of the serrated structure is λ3, and the height of each tooth of the serrated structure of the blow pipe 12 is h3. Alternatively, the inner diameter of the blower tube 12 is 50 mm to 100 mm, and the number of teeth in the serrated structure of the blower tube 12 is 8 to 30. In this embodiment, the inner diameter of the blower tube 12 is 60 mm, and the number of teeth is 12, thereby achieving both noise reduction and strength requirements. The duct assembly is made of any of PP, PC, ABS, or nylon, making it less susceptible to damage during a drop.

[0051] During the experimental verification of the sawtooth structure, the same garden hair dryer was used, running at the same motor speed and with the same air duct length. The difference was that the end of one set of air ducts 12 did not have a sawtooth structure, e.g. Figure 10 another set of blowing pipe 12 is provided at the end of the serrated structure, such as Figure 10 The middle dashed line segment compares the noise reduction effect between the two. Figure 10As shown, the solid and dashed line segments have almost corresponding narrowband noise and broadband noise distributions. Narrowband noise actually refers to a sound with a large amplitude at a certain frequency, more commonly known as a sharp sound. The sawtooth structure has no effect on the noise distribution. Both the solid and dashed line segments have corresponding sharp sounds A and B. We found that the sawtooth structure has a significant noise reduction effect on the sharp sounds: at sharp sound A, the noise level was 73.94dB without the sawtooth structure, but it dropped to 72.67dB with the sawtooth structure, a decrease of 1.27dB in the sharp sound. At sharp sound B, the noise level was 61.65dB without the sawtooth structure, but it dropped to 58.28dB with the sawtooth structure, a decrease of 3.37dB in the sharp sound. The sawtooth structure has a significant noise reduction effect on fixed-frequency sharp sounds. In fact, the serrated structure of the air outlet pipe of the air duct section 10 of the garden hair dryer of the present application significantly reduces the shrill sound, thereby improving the sound quality (sharpness) of the noise.

[0052] Of course, the air duct assembly may include not only the blowing pipe 12 but also the siphon pipe 11. The air outlet end of the blowing pipe 12 is provided with a serrated structure, and the air outlet end of the siphon pipe 11 is provided with a serrated structure, or only the air outlet end of the blowing pipe 12 is provided with a serrated structure, or only the air outlet end of the siphon pipe 11 is provided with a serrated structure. That is, the air duct assembly may not only be a single section, but may also be a plurality of air duct sections 10; and when there are multiple air duct sections 10, all air duct sections 10 may have a serrated structure (see Figure 1 ), or a portion of the air duct section 10 may be provided with a serrated structure (not shown in the figure).

[0053] When there are multiple air duct sections 10, the inner diameters of at least two adjacent air duct sections 10 are different, and the inner diameter of the air duct section 10 close to the air outlet side is larger than the inner diameter of the air duct section 10 close to the air inlet side. Figures 1 to 7 In the specific embodiment shown, the air duct section 10 has two sections, namely a blowing pipe 12 and a siphon pipe 11. The air inlet end of the siphon pipe 11 is connected to the air outlet end of the blowing pipe 12. The inner diameter of the siphon pipe 11 is larger than the inner diameter of the blowing pipe 12, so as to form a siphon air inlet gap between the air inlet end of the siphon pipe 11 and the air outlet end of the blowing pipe 12.

[0054] The hair dryer in this embodiment has an air volume mode in which the air flow is increased through the siphon tube 11 and blown out from the siphon tube 11 , and a wind speed mode in which the air flow is directly blown out from the blowing pipe 12 .

[0055] When the hair dryer is in air volume mode, the siphon tube 11 needs to be additionally installed at the outlet end of the blowpipe 12; or if the siphon tube 11 is already connected to the blowpipe 12, the positional relationship between the two needs to be changed so that the air blown out of the blowpipe 12 enters the siphon tube 11. In other words, when the air flows through the outlet duct section 10, the airflow speed is relatively fast, generating negative pressure. The outside air is replenished by atmospheric pressure and enters from the outlet end of the previous duct section 10, which increases the air volume. When the hair dryer is in air speed mode, only the blowpipe 12 is in use, while the siphon tube 11 is not used or does not operate.

[0056] Specifically, in Figure 2 or Figure 7 In the embodiment shown, the siphon tube 11 is slidably connected to the blowing pipe 12 via a connecting structure, so that the siphon tube 11 can be slidably adjusted along the axial direction of the blowing pipe 12. Specifically, the connecting structure includes a connecting sleeve 20 and a support plate 30 fixed along the circumference of the connecting sleeve 20, and the support plate 30 is fixed to the siphon tube 11. In this way, when the connecting sleeve 20 is sleeved on the outer surface of the air outlet end of the blowing pipe 12 and can slide along the blowing pipe 12, the connecting sleeve 20 can drive the siphon tube 11 to move, so as to change the positional relationship of the siphon tube 11 relative to the blowing pipe 12. Optionally, the support plate 30, the connecting sleeve 20 and the siphon tube 11 are integrally formed. Figure 2 It can be seen that the inner diameter of the connecting sleeve 20 is slightly larger than the outer diameter of the blowing pipe 12, and the outer diameter of the connecting sleeve 20 is smaller than the inner diameter of the siphon pipe 11. Under the action of the support plate 30, a siphon air intake gap is formed between the connecting sleeve 20 and the siphon pipe 11. Therefore, Figure 2 The status shown is air volume mode.

[0057] and Figure 7 Shown state is wind speed mode. When wind speed mode, it can be seen that siphon tube 11 slides backward and retreats to the position overlapping with blow pipe 12, so when the hair dryer is working, only blow pipe 12 is put into use, and siphon tube 11 has no effect.

[0058] Of course, in an embodiment not shown in the figure, the siphon tube 11 can also be installed at the air outlet end of the blowing pipe 12 in a detachable manner, such as by snapping. In the air volume mode, the siphon tube 11 is snapped onto the air outlet end of the blowing pipe 12; in the wind speed mode, the siphon tube 11 is removed, leaving only one section of the blowing pipe 12.

[0059] like Figure 11 As shown, in this embodiment, the axial fan 50 is arranged in the casing 40 to drive the air to flow. When the air flow flows from the blowing pipe 12 through the siphon tube 11, a high-speed air flow is blown out from the blowing pipe 12, forming a negative pressure near the blowing pipe 12. The external atmospheric pressure replenishes the external air flow, and the gas flow rate will become larger.

[0060] like Figures 1 to 4 As shown, in this embodiment, the air outlet end of the siphon pipe 11 and the air outlet end of the blowing pipe 12 are both provided with corresponding sawtooth structures. Thus, the number of sawtooth structures is two, namely, a first sawtooth structure 111 provided on the air outlet end of the siphon pipe 11, and a second sawtooth structure 121 provided on the air outlet end of the blowing pipe 12. Figure 5 As shown, the sawtooth structure can be provided only at the air outlet end of the siphon tube 11, and the blower tube 12 is not provided with a sawtooth structure. Figure 6 As shown, the serrated structure can also be provided only at the outlet end of the blowpipe 12, without being provided on the siphon pipe 11. It is understandable that, compared with the embodiment in which the air duct assembly only includes the blowpipe and the embodiment in which the air duct assembly includes both the blowpipe and the siphon pipe, the embodiment with only the blowpipe clearly produces less noise overall, as the siphon pipe introduces a new noise source. The embodiment in which the serrated structure is provided on both the blowpipe and the siphon pipe achieves significantly better noise reduction than the embodiment in which only the blowpipe or only the siphon pipe has the serrated structure.

[0061] In the embodiment where both the blowing pipe 12 and the siphon pipe 11 are provided with sawtooth structures, as the airflow flows from the blowing pipe 12 through the siphon pipe 11, outside air is replenished into the siphon pipe 11 through the siphon intake gap. The second sawtooth structure 121 at the outlet end of the blowing pipe 12 breaks up large vortices in the airflow blown out of the blowing pipe, reducing the vortex volume and lowering noise. When the airflow flows out of the outlet end of the siphon pipe 11, the first sawtooth structure 111 provided at the outlet end of the siphon pipe 11 can further break up large vortices, reducing the vortex volume and further reducing noise.

[0062] like Figures 1 to 4 As shown, the first serrated structure 111 and the second serrated structure 121 have multiple teeth. The multiple teeth of the first serrated structure 111 are sequentially arranged along the circumference of the siphon tube 11 to form a ring-shaped structure. The multiple teeth of the second serrated structure 121 are also sequentially arranged along the circumference of the blowing pipe 12 to form a ring-shaped structure. In this embodiment, the multiple teeth of the first serrated structure 111 and the second serrated structure 121 have a better vortex breaking effect. When the airflow within the siphon tube 11 and the blowing pipe 12 comes into contact with the outside air, vortices are generated in all directions. The multiple teeth of the first serrated structure 111 are sequentially arranged along the circumference of the siphon tube 11 to form a ring-shaped structure, which has a better effect on breaking up large vortices, further achieving the purpose of reducing noise. The multiple teeth of the second serrated structure 121 are also sequentially arranged along the circumference of the blowing pipe 12 to form a ring-shaped structure, which also has a better effect on breaking up large vortices, further achieving the purpose of reducing noise.

[0063] The design of the serrated structure of the blowpipe and the siphon tube needs to be designed from different angles. When the hair dryer falls, since the siphon tube 11 hits the ground first, the possibility of damage to the first serrated structure 111 of the siphon tube 11 is higher. Therefore, the first serrated structure 111 of the siphon tube 11 needs to be more stable and less sharp. When the hair dryer falls, the outer diameter of the blowpipe 12 is smaller than the outer diameter of the siphon tube 11. The second serrated structure 121 of the blowpipe 12 will not directly contact the ground and will not be easily damaged. Therefore, the second serrated structure 121 of the blowpipe 12 can be made sharper to achieve a better noise reduction effect.

[0064] like Figure 3 As shown, the bottom width of each tooth of the first sawtooth structure 111 of the siphon tube 11 is λ1, and the height of each tooth of the first sawtooth structure 111 of the siphon tube 11 is h1. The function of the first sawtooth structure 111 is to break up the large vortex at the outlet end, reduce the vortex volume, and reduce noise. Although the sharper the sawtooth of the first sawtooth structure 111, the better the noise reduction effect, it is also easy to break. Therefore, it is necessary to limit the ratio between the height of the tooth and the bottom width of the tooth. In this embodiment,

[0065] like Figure 4 As shown, the bottom width of each tooth of the second sawtooth structure 121 of the blowing pipe 12 is λ2, and the height of each tooth of the second sawtooth structure 121 of the blowing pipe 12 is h2. Therefore, the serration structure of the blowing pipe 12 is sharper, achieving a better noise reduction effect, and the serration structure of the siphon pipe 11 tends to be blunter, taking into account its strength requirements.

[0066] In addition, the inner diameter of the blowing pipe 12 is 50-100 mm, and the number of teeth of the serration structure of the blowing pipe 12 is 8-30; for the inner diameter of the siphon pipe 11 is 50-100 mm, the number of teeth of the serration structure of the siphon pipe 11 is 12-36. Optionally, the ratio of the number of teeth of the serration structure of the blowing pipe 12 to the number of teeth of the serration structure of the siphon pipe 11 is 0.3-1.2.

[0067] When the above relationship is satisfied, in a specific embodiment, the inner diameter of the siphon tube 11 is larger than the inner diameter of the blowing tube 12, and the number of serrations on the siphon tube 11 is larger than the number of serrations on the blowing tube 12. The siphon tube 11 has 16 teeth, and the blowing tube 12 has 12 teeth. Furthermore, the second serration structure 121 of the blowing tube 12 has 12 teeth, and the first serration structure 111 of the siphon tube 11 has 16 teeth.

[0068] When the hair dryer of the above embodiment is in the air volume mode, the wind speed is 40m / s-70m / s, the Mach number is 0.1-0.2, and the squeal noise reduction is 1.8db-3.4db.

[0069] Furthermore, the aforementioned analysis leads to the conclusion that a sharper second serration structure 121 of the blowpipe 12 achieves better noise reduction. Therefore, in the aforementioned experiments, the inventors also conducted tests to verify this, resulting in Table 1, which shows the test results for a comparative example and an embodiment with two sets of serration structures having different ratios of tooth height to tooth width.

[0070] Table 1. Test results of comparative examples and embodiments with different ratios of tooth height to tooth width for two sets of sawtooth structures

[0071]

[0072] As shown in Table 1, a larger ratio of tooth height to tooth width results in sharper teeth and greater noise reduction. Furthermore, the actual measured squeal reduction was significantly better than the predicted reduction, which was unexpected. This demonstrates that the sawtooth structure's superior squeal reduction significantly improves the hair dryer's overall noise level.

[0073] The previous test was conducted on the hair dryer in air volume mode, and achieved good verification results. The following will further verify the hair dryer in air speed mode.

[0074] like Figure 7 As shown, in wind speed mode, the wind speed is 50m / s-90m / s, the Mach number is 0.15-0.27, and the squeal noise reduction is 1.8dB-3.4dB. Because the siphon 11 introduces a new noise source, the overall noise in air volume mode is greater than that in wind speed mode, and the noise reduction in air volume mode is less than that in wind speed mode.

[0075] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, tasks, devices, components and / or combinations thereof.

[0076] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0077] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A hair dryer, characterized in that: The output power of the hair dryer is 500W-1500W, the wind speed of the hair dryer is 40m / s-100m / s, and the air volume is 200cfm-800cfm. The hair dryer includes: A housing (40), wherein the housing (40) is provided with a grip portion (41); an axial flow fan (50), the axial flow fan (50) being located in the housing (40); a motor (60), the motor (60) driving the axial flow fan (50) to generate airflow; An air duct assembly, the air duct assembly being connected to the housing (40), and the air duct assembly comprising at least one air duct section (10), one end of the at least one air duct section (10) away from the housing (40) being an air outlet end, the air outlet end of the at least one air duct section (10) being provided with a sawtooth structure, the sawtooth structure extending in the direction of air outlet, and the teeth of the sawtooth structure gradually shrinking along the direction of air outlet to form a tip portion; The at least one air duct section (10) comprises only a blowing pipe (12), the bottom width of each tooth of the sawtooth structure of the blowing pipe (12) is λ3, the height of each tooth of the sawtooth structure of the blowing pipe (12) is h3, ; The thickness of the teeth of the serrated structure gradually decreases along the direction of the air outlet.

2. The hair dryer according to claim 1, characterized in that The sawtooth structure has a plurality of teeth, and the plurality of teeth are sequentially arranged along the circumference of the air duct section (10) to form a ring-shaped structure.

3. The hair dryer according to claim 1, wherein The teeth are of pointed type, or the sawtooth structure is of sinusoidal type.

4. The hair dryer according to claim 1, wherein The teeth of the sawtooth structure have an inner tooth surface facing the inside of the air duct section (10), and an outer tooth surface facing the outside of the air duct section (10). The inner side surface of the tooth and the outer side surface of the tooth are planes, and the angle between the inner side surface of the tooth and the outer side surface of the tooth is 0-15 degrees; or The inner side surface of the tooth is an arc surface, and the arc surface bulges in a direction away from the outer side surface of the tooth.

5. The hair dryer according to claim 1, wherein The sawtooth structure has a plurality of recesses (112) on the inner side surface of the teeth facing the inside of the air duct section (10), and / or the air duct section (10) has a plurality of recesses (112) on the inner wall of the tube close to the sawtooth structure.

6. The hair dryer according to claim 5, characterized in that The cross-sectional shape of the plurality of pits (112) is circular, the diameter of the plurality of pits (112) is 2-5 mm, and the spacing between the centers of the plurality of pits (112) is 2-10 mm.

7. The hair dryer according to any one of claims 1 to 6, characterized in that The inner diameter of the blowing pipe (12) is 50 mm to 100 mm, and the number of teeth of the sawtooth structure of the blowing pipe (12) is 8 to 30.

8. The hair dryer according to any one of claims 1 to 6, characterized in that The at least one air duct section (10) comprises two air duct sections (10), and the two air duct sections (10) are: Blowing pipe (12); A siphon pipe (11), the siphon pipe (11) being in communication with the blowing pipe (12), the inner diameter of the siphon pipe (11) being larger than the inner diameter of the blowing pipe (12), so as to form a siphon air inlet gap between the air inlet end of the siphon pipe (11) and the air outlet end of the blowing pipe (12); The air outlet end of the blowing pipe (12) is provided with the sawtooth structure, and / or the air outlet end of the siphon pipe (11) is provided with the sawtooth structure; The bottom width of each tooth of the sawtooth structure of the siphon tube (11) is λ1, the height of each tooth of the sawtooth structure of the siphon tube (11) is h1, ; The bottom width of each tooth of the sawtooth structure of the blowing pipe (12) is λ2, the height of each tooth of the sawtooth structure of the blowing pipe (12) is h2, , .

9. The hair dryer according to claim 8, characterized in that The hair dryer has an air volume mode in which the air flow is increased through the siphon tube (11) and blown out from the siphon tube (11), and a wind speed mode in which the air flow is blown out directly from the blowing tube (12).

10. The hair dryer according to claim 9, characterized in that When the hair dryer is in the air volume mode, the wind speed is 40m / s-70m / s, the Mach number is 0.1-0.2, and the sawtooth structure reduces the shrill noise of the hair dryer by 1.8db-3.4db.

11. The hair dryer according to claim 9, characterized in that When the hair dryer is in the wind speed mode, the wind speed is 50m / s-90m / s, the Mach number is 0.15-0.27, and the sawtooth structure reduces the shrill noise of the hair dryer by 1.8db-3.4db.

12. The hair dryer according to claim 8, characterized in that The inner diameter of the blowing pipe (12) is 50 mm to 100 mm, and the number of teeth of the sawtooth structure of the blowing pipe (12) is 8 to 30.

13. The hair dryer according to claim 12, characterized in that The inner diameter of the siphon tube (11) is 50-100 mm, and the number of teeth of the sawtooth structure of the siphon tube (11) is 12-36.

14. The hair dryer according to claim 8, characterized in that The serrated structure is provided on both the air outlet end of the blowing pipe (12) and the air outlet end of the siphon pipe (11), and the ratio of the number of teeth of the serrated structure of the blowing pipe (12) to the number of teeth of the serrated structure of the siphon pipe (11) is 0.3-1.

2.

15. The hair dryer according to any one of claims 1 to 6, characterized in that The material of the air duct section (10) is any one of PP, PC, ABS and nylon.

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