Air duct structure, machine head assembly and fan

Abstract

The utility model relates to an air duct structure, a machine head assembly and a fan. The air duct structure is used for the fan with a heating body. An air supply duct is arranged in the air duct structure and provided with an air inlet and an air outlet, and the direction from the air inlet to the air outlet is the air supply direction. The air supply duct comprises a contraction section and a straight section, in the air supply direction, the straight section is located on the downstream of the contraction section, and the through-flow area of the contraction section is gradually reduced in the air supply direction. According to the air duct structure, the scheme of the contraction section and the straight section is adopted in the air supply duct, the contraction section is located on the upstream, the gradually-reduced circulation area of the contraction section can gather the supplied air flow and accelerate the supplied air flow, and the straight section is located on the downstream, so that the supplied air flow can be stabilized, and the flow direction of the supplied air flow can be adjusted. The two air duct sections are combined, so that the air outlet is straight, the air speed of an outlet is high, the air supply distance is long, particularly during heating, the air volume of the outlet and the heat flux per unit area are ensured, and the air speed of the outlet and the heating distance are increased at the same time.

Description

Technical Field

[0001] The present application relates to the technical field of fans, and particularly to an air duct structure, a head assembly and a fan. Background Art

[0002] Electric fans or electric heaters are essential household appliances. In recent years, combined heating and cooling products, such as combined heating and cooling tower fans and combined heating and cooling cold fans, have been successively introduced into the market. They can be used for cooling in summer and heating in winter, serving two purposes with one device, and have been recognized by the market. Due to its characteristics of large-angle oscillation and long-distance air circulation, the circulation fan is deeply favored by consumers. The circulation fan with a combined warm air function can achieve a large heating area and long-distance heating. It can blow cold air and also heat, realizing the function of one device for both cooling and heating, and reducing storage and idleness.

[0003] The whole head of the circulation fan is cylindrical, with a small space. It is impossible to use a dense PTC heating element, and only a heating wire with a circumferential distribution and relatively sparse arrangement can be used. In related technologies, due to the heat transfer characteristics of the heating wire itself, in order to ensure the heat flux per unit area to meet the heating effect requirements, it is necessary to reduce the fan speed to reduce the air volume. However, reducing the speed will undoubtedly also reduce the air supply distance, making the fan unable to meet the requirements of long-distance heating and easily resulting in uneven air output. Summary of the Utility Model

[0004] Based on this, it is necessary to provide an air duct structure, a head assembly and a fan that can improve the air supply distance and make the air output more straight for the above problems.

[0005] An air duct structure for a fan with a heating element. The air duct structure has an air supply duct. The air supply duct has an air inlet and an air outlet, and the direction from the air inlet to the air outlet is the air supply direction.

[0006] The air supply duct includes a contraction section and a straight section. In the air supply direction, the straight section is located downstream of the contraction section, and the flow area of the contraction section gradually decreases along the air supply direction.

[0007] In one embodiment, the contraction section is a conical section. The air supply duct further includes an arc section, and in the air supply direction, the conical section is located downstream of the arc section.

[0008] In one embodiment, the angle between the generatrix of the conical section and the axis of the air supply duct is α, and 0°≤α≤10°.

[0009] In one embodiment, one end of the straight section away from the contraction section forms the air outlet; and / or, one end of the contraction section away from the straight section forms the air inlet.

[0010] A head assembly includes a heating element, a blower fan, and the above-described air duct structure. Among them, the blower fan is disposed in the air supply duct, and the heating element is disposed at one end of the air duct structure.

[0011] In one embodiment, the outer diameter of the heating element is d1, the diameter of the air inlet is d2, and d2 ≤ d1.

[0012] In one embodiment, the diameter of the blower fan is d4, the diameter of the air outlet is d3, and d4 ≤ d3 ≤ 1.1d4.

[0013] In one embodiment, the height of the blades of the blower fan in the axial direction of the air supply duct is h, the length of the straight section in the air supply direction is b, and 0 < b < 0.5h.

[0014] In one embodiment, the head assembly further includes a protective net disposed on the side of the heating element facing away from the air duct structure; and / or, the head assembly further includes a filter bracket disposed on the side of the heating element facing away from the air duct structure.

[0015] A fan includes the above-described air duct structure or the above-described head assembly.

[0016] For the above-described air duct structure, head assembly, and fan, the air supply duct adopts a scheme of a contraction section + a straight section. The contraction section is located upstream, and its gradually decreasing flow area can converge the air supply airflow and accelerate the air supply airflow. The straight section is located downstream, which can stabilize the air supply airflow and adjust the flow direction of the air supply airflow. The combination of the two air duct sections makes the air outlet straight, the outlet air velocity high, and the air supply distance far. Especially during heating, it ensures the outlet air volume and the heat flux per unit area, while increasing the outlet air velocity and the heating distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of a head assembly with an air duct structure in an embodiment of the present application.

[0019] Figure 2 It is Figure 1 a schematic cross-sectional structural diagram of the head assembly shown.

[0020] Figure 3 It is Figure 1Partial structural schematic diagram of the nose component shown

[0021] Figure 4 is Figure 1 Structural schematic diagram of the air duct structure and the air blade in the nose component shown

[0022] Figure 5 is Figure 1 Another angle structural schematic diagram of the nose component shown

[0023] Figure 6 is Figure 1 Exploded structural schematic diagram of the nose component shown

[0024] Figure 7 is Figure 5 Structural schematic diagram of the heating element in the nose component shown

[0025] Figure 8 is Figure 5 Structural schematic diagram of the rear grille and the protective net in the nose component shown

[0026] Figure 9 Structural schematic diagram of the air duct structure and the air blade of Comparative Example 1

[0027] Figure 10 Structural schematic diagram of the air duct structure and the air blade of Comparative Example 2

[0028] Figure 11 Structural schematic diagram of the air duct structure and the air blade of Comparative Example 3

[0029] Explanation of reference numerals: 100, air duct structure; 10, air supply duct; 11, air inlet; 12, air outlet; 13, contraction section; 14, straight section; 15, arc section; 200, nose component; 210, heating element; 211, support frame; 2111, spoke; 212, heating wire; 220, air blade; 230, rear grille; 240, motor; 250, front grille; 260, air duct housing; 270, filter support; 280, protective net; 300, air duct body Detailed implementation manners

[0030] In order to make the above objects, features and advantages of the present application more obvious and understandable, the following will describe the detailed implementation manners of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below

[0031] In the description of the present application, it should be understood that if there are terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application.

[0032] In addition, if there is a term "and / or", "and / or" is only a description of the relationship between associated objects and indicates that there can be three relationships. For example, A and / or B can represent the relationship between A and B: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after it. If there are terms such as "first" and "second", these terms are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present application, if there is a term "plurality", the meaning of "plurality" is at least two, such as two, three, four, five, etc., unless otherwise specifically defined.

[0033] In the present application, unless otherwise clearly specified and limited, if there are terms such as "install", "connect", "couple", "fix", etc., these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the connection inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0034] In this application, unless otherwise clearly specified and defined, if there is a description such as a first feature being "on" or "under" a second feature, its meaning can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is less than that of the second feature.

[0035] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If present, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in this application are only for the purpose of illustration and do not represent the only implementation.

[0036] Except as described in the background art, when using heating wires that are circumferentially distributed and relatively sparse, when the whole machine is heating, the hot air blown out may be mixed with cold air, resulting in a poor experience. In the related art, there is a circulation fan that controls the radial air intake of the fan through a driving device, and all the air flows into the heating body axially, improving the heating body feeling effect. However, as described in the background art, limited by the heat transfer characteristics of the heating wire itself, if the air volume of the circulation fan is large, the heat flux per unit area will be reduced, resulting in a low outlet temperature and poor heating effect, and it cannot meet the requirements of long-distance heating. At the same time, the air outlet is prone to unevenness.

[0037] Improving the instant heating effect means that it is necessary to increase the outlet temperature, that is, to increase the temperature change. According to formula 1: Q = C p mΔT and ΔT = Q / C p m = q / C p , it can be seen that the outlet temperature can be increased by increasing the heat flux per unit area q. The ways to increase the heat flux per unit area q include reducing the rotation speed or reducing the air outlet area. However, if the rotation speed is reduced and the air volume is reduced to increase the heat flux per unit area q, it will lead to a weakening of the overall air supply distance and a poor long-distance heating effect. And simply restricting the air outlet area will increase the air volume loss when the circulation fan blows cold air. Therefore, it is necessary to provide a duct and a fan that can achieve a large air volume when blowing cold air, a good instant heating effect when heating, a long heating distance, and a straight air supply.

[0038] For the above problems, please refer to Figures 1 to 4The air duct structure 100 provided in one embodiment of the present application is used for a fan having a heating element 210. The air duct structure 100 has an air supply duct 10, which has an air inlet 11 and an air outlet 12. The direction from the air inlet 11 to the air outlet 12 is the air supply direction (corresponding to Figure 2 The air supply duct 10 includes a contraction section 13 and a straight section 14. In the air supply direction, the straight section 14 is located downstream of the contraction section 13, and the flow area of the contraction section 13 gradually decreases along the air supply direction.

[0039] It can be understood that the fan blades 220 can be arranged in the air supply duct 10. Driven by the rotating fan blades 220, the air flow flows in the air supply duct 10 along the air supply direction (such as Figure 2 The fan having the heating element 210 has at least a warm air mode. In this mode, the heating element 210 operates, heating the air flow to form warm air. Furthermore, the fan may have a cool air mode. In this mode, the heating element 210 does not operate, and the air flow is directly delivered outward without being heated.

[0040] The contraction section 13 is connected and communicated with the straight section 14, and the contraction section 13 is located upstream of the straight section 14, that is, the supply air flow flows from the contraction section 13 to the straight section 14, wherein the flow area of the contraction section 13, that is, the cross-sectional area perpendicular to the air supply direction, gradually decreases.

[0041] The above-mentioned air duct structure 100, its air supply duct 10 adopts the solution of contraction section 13 + straight section 14. The contraction section 13 is located upstream, and its gradually decreasing flow area can gather the supply air flow and accelerate the supply air flow. The straight section 14 is located downstream, which can stabilize the supply air flow and adjust the flow direction of the supply air flow. The combination of the two air duct sections makes the air outlet straight, the outlet wind speed high, and the air supply distance long. Especially when heating, it ensures the outlet air volume and heat flux per unit area, while improving the outlet wind speed and heating distance. According to formula 1, if the initial ambient temperature is 10℃~15℃, when the outlet temperature reaches 60°, the air volume required for heating is about 150m 3 / h~170m 3 / h, the air duct structure 100 can meet this requirement.

[0042] In some embodiments, the end of the straight section 14 away from the contraction section 13 is formed as an air outlet 12. Thus, one end of the straight section 14 is formed as the air outlet 12, and the air flow can be output outward after being rectified by the straight section 14, which helps to improve the straightness of the air output.

[0043] In some embodiments, one end of the converging section 13 away from the straight section 14 is formed as the air inlet 11. Thus, the external air flow can enter the converging section 13 from the air inlet 11 and be converged and accelerated by the converging section 13.

[0044] In some embodiments, the converging section 13 is a conical section, and the air supply duct 10 further includes an arc section 15. In the air supply direction, the conical section is located downstream of the arc section 15.

[0045] It can be understood that the arc section 15 extends in an arc along the axial direction of the air supply duct 10, its generatrix is an arc, and specifically it can be a circular arc, and the center of the circle is outside the air supply duct 10. The conical section extends in a conical shape along the axial direction of the air supply duct 10, and its generatrix is a straight line obliquely intersecting the axial direction of the air supply duct 10.

[0046] The conical section can be directly connected to the arc section 15, and the two are tangent at the connection, that is, the surface of the conical section is tangent to the surface of the arc section 15 at the connection with the arc section 15, that is, the slope of the generatrix of the conical section is consistent with the slope of the tangent line of the generatrix of the arc section 15 at the connection.

[0047] Thus, the arc section 15 is upstream and can effectively gather the air flow into the air supply duct 10 within a short distance, that is, divert it towards the air inlet 11, which helps to increase the air volume of the air flow. And under the guidance of the arc section 15, the transition of the air flow is smoother and the wind resistance is lower. The conical section is downstream and can smoothly accelerate the air flow in it, increasing the overall speed of the air flow. After the air flow is accelerated by the conical section, it enters the straight section 14.

[0048] In some embodiments, the angle between the generatrix of the conical section and the axial direction of the air supply duct 10 is α, and 0° ≤ α ≤ 10°. Preferably, 5° ≤ α ≤ 6°, and α can be but is not limited to 5°, 5.25°, 5.5°, 5.75°, 6°, etc., which are not specifically defined here.

[0049] The air volume generated by the fan through the air duct structure 100 has a direct relationship with the angle of the conical section, and as the taper increases, the air volume first increases and then decreases.

[0050] Thus, by selecting a suitable angle for the conical section, the air volume can be adjusted to a higher level to meet the requirements of cold and warm air.

[0051] In some other embodiments, in the air supply direction, the converging section 13 can also extend in an arc or include an arc extension part and a conical extension part, etc., as long as the flow-through area can be gradually reduced, which is not specifically defined here.

[0052] Please refer to Figure 5 and Figure 6, the present application also provides a head assembly 200, which includes a heating element 210, a blower fan 220, and the above-mentioned air duct structure 100. Among them, the blower fan 220 is arranged in the air supply duct 10, and the heating element 210 is arranged at one end of the air duct structure 100.

[0053] Understandably, to achieve its normal function, the head assembly 200 may further include a conventional rear grille 230, a motor 240, a front grille 250, an air duct housing 260, etc., which will not be elaborated here. Among them, the rear grille 230 is located upstream of the air duct structure 100 and faces the air inlet 11. The rear grille 230 is also the air inlet grille. The motor 240 can be located in the air duct. An installation bracket is provided in the air duct structure 100. The motor 240 is fixed on the installation bracket. The blower fan 220 is installed on the output shaft of the motor 240 and is located in the air supply duct 10. The front grille 250 is located downstream of the air duct structure 100 and specifically seals the air outlet 12. The front grille 250 is also the air outlet grille. The air duct housing 260 wraps around the air duct structure 100 to protect the air duct structure 100.

[0054] Please refer to Figure 7 specifically, the heating element 210 includes a support frame 211 and heating wires 212. The support frame 211 has a plurality of spokes 2111 that radially extend perpendicular to the axial direction of the air duct structure 100. The heating wires 212 are arranged in a circumferential manner around the axis and are arranged on the spokes 2111. Compared with the PTC heating element, this heating element 210 has good permeability and can effectively reduce the air resistance.

[0055] The heating element 210 is arranged at one end of the air duct structure 100 close to the air inlet 11, that is, the heating element 210 is located upstream of the air duct structure 100. In this way, the air flow entering the air duct structure 100 can be fully heated by the heating element and then send out air along the air supply duct 10 in the air duct structure 100.

[0056] In some embodiments, the outer diameter of the heating element 210 is d1, and the diameter of the air inlet 11 is d2, and d2 ≤ d1.

[0057] In this way, along the axial projection of the air supply duct 10, the heating element 210 can cover the air inlet 11, ensuring that after the air flow enters axially, all of it passes through the heating element 210. After the air flow is heated, it all flows into the air supply duct 10, effectively reducing the probability of cold air leakage in the warm air mode.

[0058] Further, the diameter of the air outlet 12 is d3, and d3 < d2, ensuring that the air inlet area is larger than the air outlet area. Specifically, one end of the conical section in the axial direction is the air inlet 11, and its area is the air inlet area. The other end of the conical section in the axial direction is connected to the straight section 14 and has the same flow area as the straight section 14. One end of the straight section 14 forms the air outlet 12. Therefore, the area of the other end of the conical section in the axial direction is equal to the air outlet area. Since the flow area of the conical section gradually decreases in the air supply direction, the air outlet area must be smaller than the air inlet area.

[0059] In some embodiments, the diameter of the fan blade 220 is d4, and d4 ≤ d3 ≤ 1.1d4. In other words, along the axial projection of the air supply duct 10, the fan blade 220 is slightly smaller than the air outlet 12.

[0060] In this way, the air supply airflow formed by driving the fan blade 220 fully passes through the air outlet 12, with relatively low flow resistance. At the same time, the air outlet 12 should not be too large, as this will cause the air supply airflow to easily diverge, and during heating, the heat flux will decrease and the heating effect will deteriorate.

[0061] In some embodiments, in the axial direction of the air supply duct 10, the length of the duct structure 100 is L1, the length of the conical section is a, and the length of the straight section 14 is b, where L1 > a + b.

[0062] In some embodiments, the height of the blade of the fan blade 220 in the axial direction of the air supply duct 10 is h, and the length of the straight section 14 in the air supply direction is b, and 0 < b < 0.5h. Specifically, b is not less than 25 mm and not more than 35 mm.

[0063] In this way, after the air supply airflow is accelerated through the conical section, it enters the straight section 14. Appropriately selecting the length of the straight section 14 can effectively control the frictional loss of the air supply airflow in the straight section 14 and ensure the air outlet velocity.

[0064] In some embodiments, the head assembly 200 further includes a filter net and a filter net bracket 270. The filter net bracket 270 is disposed on the side of the heating element 210 facing away from the duct structure 100 and is used for installing the filter net.

[0065] The filter net bracket 270 can be disassembled and assembled together with the rear grille 230 and can install or replace the filter net. The filter net can filter the airflow flowing from the rear grille 230 into the air supply duct 10.

[0066] In this way, the head assembly 200 can install the filter net with the help of the filter net bracket 270 to pre-filter the air supply airflow and improve the air supply quality. In addition, the filter net and the filter net bracket 270 can also play a protective role, separating the heating element 210 from the outside.

[0067] Please refer to Figure 8, in some embodiments, the nose assembly 200 further includes a protective net 280 disposed on a side of the heating element 210 facing away from the air duct structure 100.

[0068] In this way, the protective net 280 can separate the heating element 210 to prevent accidental contact by the user. Especially during the disassembly and assembly of the rear grille 230 and the filter holder 270, and after the rear grille 230 and the filter holder 270 are removed, the protective net 280 can play a protective role to prevent the user from directly contacting the heating element 210.

[0069] In addition, when both the protective net 280 and the filter holder 270 are provided, double protection can be formed for the heating element 210. First, the filter membrane is covered on the filter holder 270, and the filter holder 270 is assembled to the rear grille 230. The rear grille 230, the filter holder 270 and the filter screen filter dust and at the same time play a protective role. When the user disassembles the rear grille 230 and the filter holder 270 together, the protective net 280 blocks to prevent the user from touching the heating element 210. Therefore, with the double protection design of the filter holder 270 and the protective net 280, the filter can be disassembled and replaced more reassuringly.

[0070] Among them, the grille mesh patterns of the rear grille 230 and the protective net 280 are basically the same in the axial projection. In this way, in the case of two layers of nets, the grille gaps are not staggered, ensuring the maximum air inlet smoothness.

[0071] Specifically, the protective net 280 is made of a plastic net similar in shape to the rear grille 230, or an iron net can also be used. The iron net has good permeability and better resistance than the plastic net. When the heating element 210 is working, the surface temperature of the plastic net is lower and the risk of being scalded is lower.

[0072] Next, the air duct structure 100 in the present application will be compared with the air duct bodies 300 of Comparative Example 1 and Comparative Example 2. Among them, in Comparative Example 1, the air duct body 300 adopts a full straight channel (as Figure 9 shown), in Embodiment 2, the air duct body 300 adopts a full straight channel + straight - flat - straight section scheme (as Figure 10 shown), and in Embodiment 3, the air duct body 300 adopts a full conical channel scheme (as Figure 11 shown). The air duct bodies 300 in Comparative Example 1 and Comparative Example 2 both have problems of small outlet air speed, divergent air outlet, and short air supply distance. The outlet air speed of the air duct body 300 in Comparative Example 3 will increase, the degree of air aggregation will increase, but the air outlet is not straight enough and is a bit skewed. When the channel inclination angle is increased from 0 to 8°, as the taper increases, the air volume shows a trend of increasing first and then decreasing, as shown in the following table:

[0073]

[0074] For the air duct structure 100 of the present application, the air volumes in the cold air mode and the warm air mode are as shown in the following table:

[0075]

[0076] The air duct structure 100 of the present application is compared with the air duct bodies 300 of Comparative Examples 1, 2, and 3, and the test data are as shown in the following table:

[0077]

[0078] It can be easily seen that the air duct structure 100 has a significant improvement in the heating effect and long-distance heating compared with Comparative Examples 1, 2, and 3.

[0079] The above-mentioned machine head assembly 200 has a cold air mode and a warm air mode. Cold air mode: The heating element 210 is not turned on, the motor 240 drives the wind blade 220 to rotate, the air flow enters the rear grid 230 from the outside, the filter screen filters dust, etc. and then passes through the protective net 280, and then enters the air supply duct 10 through the heating element 210. Under the rotation of the wind blade 220, the air flow passes through the air supply duct 10 and then accelerates to flow out through the front grid 250 to supply air outward. Warm air mode: The flow direction of the air flow is generally the same as that in the cold air mode, but the heating element 210 needs to be turned on. The air flow enters from the rear grid 230, passes through the filter screen and the protective net 280 in sequence, and passes through the working heating element 210. The air flow is heated by the heating element 210 to form a warm air flow, and flows out through the front grid 250 under the action of the wind blade 220 to supply air outward.

[0080] The present application also provides a fan, including the above-mentioned air duct structure 100 or the above-mentioned machine head assembly 200.

[0081] It can be understood that the fan can be, but is not limited to, a warm air fan, a cold and warm dual-use fan, etc., and specifically can be a circulation fan, as long as it has a heating element and has a warm air mode capable of delivering warm air outward, and no specific limitation is made here.

[0082] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as these combinations of technical features do not conflict, they should all be considered as the scope described in this specification.

[0083] The above-described embodiments only represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An air duct structure, characterized in that, For a fan with a heating element (210), there is an air supply duct (10) in the air duct structure. The air supply duct (10) has an air inlet (11) and an air outlet (12). The direction from the air inlet (11) to the air outlet (12) is the air supply direction; The air supply duct (10) includes a contraction section (13) and a straight section (14). In the air supply direction, the straight section (14) is located downstream of the contraction section (13), and the flow-through area of the contraction section (13) gradually decreases along the air supply direction.

2. The air duct structure according to claim 1, wherein The contraction section (13) is a conical section. The air supply duct (10) further includes an arc section (15), and in the air supply direction, the conical section is located downstream of the arc section (15).

3. The air duct structure according to claim 2, wherein, The angle between the generatrix of the conical section and the axis of the air supply duct (10) is α, and 0° ≤ α ≤ 10°.

4. The air duct structure according to claim 1, characterized in that, One end of the straight section (14) away from the contraction section (13) forms the air outlet (12); and / or, one end of the contraction section (13) away from the straight section (14) forms the air inlet (11).

5. A head assembly, characterized in that, It includes a heating element (210), a fan blade (220), and the air duct structure according to any one of claims 1-4. Among them, the fan blade (220) is arranged in the air supply duct (10), and the heating element (210) is arranged at one end of the air duct structure.

6. The nose component according to claim 5, characterized in that The outer diameter of the heating element (210) is d1, the diameter of the air inlet (11) is d2, and d2 ≤ d1.

7. The nose component according to claim 5, characterized in that, The diameter of the fan blade (220) is d4, the diameter of the air outlet (12) is d3, and d4 ≤ d3 ≤ 1.1d4.

8. The nose component according to claim 5, characterized in that, The height of the blade of the fan blade (220) in the axial direction of the air supply duct (10) is h, the length of the straight section (14) in the air supply direction is b, and 0 < b < 0.5h.

9. The nose component according to claim 5, characterized in that, The head assembly further includes a protective net (280), and the protective net (280) is arranged on the side of the heating element (210) facing away from the air duct structure; and / or, the head assembly further includes a filter screen support (270), and the filter screen support (270) is arranged on the side of the heating element (210) facing away from the air duct structure.

10. A fan, characterized in that, It includes the air duct structure according to any one of claims 1-4 or the head assembly according to any one of claims 5-9.

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