A fan and a range hood

Abstract

The present invention relates to the technical field of range hoods, and specifically discloses a fan and a range hood, wherein the fan comprises a volute, a power member and an impeller, wherein the power member is arranged in the volute, the impeller is connected to the output end of the power member by transmission, and the blades of the impeller are arranged at an angle with the axial direction of the output shaft of the power member along the width direction of the volute and are not perpendicular. The above arrangement allows the circumferential non-uniform airflow flowing out of the blades to be dispersed on the volute tongue surface in a direction perpendicular to the output shaft, that is, the pulse airflow acting on the volute tongue surface is phase-shifted, thereby reducing the pulse force generated on the volute tongue surface, and greatly reducing the noise of the fan.

Description

Technical Field

[0001] The present invention relates to the technical field of range hoods, and in particular to a fan and a range hood. Background Art

[0002] At present, with the improvement of people's living standards, range hoods are gradually becoming popular in ordinary households. Range hoods are constantly developing. Range hoods not only need to meet the smoke extraction effect, but also need to consider the noise problem during the smoking process.

[0003] The range hood includes an outer shell and a fan arranged in the outer shell. The fan includes a volute fixed on the outer shell, an impeller rotatably arranged inside the volute, and a power component connected to the impeller in a transmission manner. The impeller rotates under the action of the power component, and the uneven airflow generated during the rotation will flow to the volute and flow out from the outlet of the volute under the guidance of the volute. However, the existing fan structure will generate relatively large noise during the working process. Summary of the invention

[0004] The object of the present invention is to provide a fan and a range hood to solve the problem of high noise during operation of the fan in the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides a fan, comprising:

[0007] snail shell;

[0008] A power member, wherein the power member is disposed in the volute;

[0009] An impeller is drivingly connected to the output end of the power member, and the blades of the impeller are arranged at an angle along the width direction of the volute to the axial direction of the output shaft of the power member and are not perpendicular.

[0010] Preferably, the angle between the blade and the axial direction of the output shaft of the power component is 12°-16°.

[0011] Preferably, the fan further comprises a transition section, and the transition section is arranged at the outlet of the volute.

[0012] Preferably, the volute includes a volute front plate, a volute rear plate and a volute side plate, and the volute side plate is connected between the volute rear plate and the volute front plate; the blades are inclined to the transition section along the direction from the volute rear plate to the volute front plate.

[0013] Preferably, the transition section comprises a front curved surface, a left curved surface, a rear curved surface and a volute tongue surface which are connected in sequence, the lower ends of the front curved surface, the left curved surface, the rear curved surface and the volute tongue surface are all straight, the front curved surface and the rear curved surface are respectively used to connect with the volute front plate and the volute rear plate; the volute tongue surface and the left curved surface are respectively used to connect with the starting end and the end of the volute side plate; and / or

[0014] The volute tongue surface of the transition section is located inside the shell, the distance between the volute front plate and the volute rear plate is B, the distance between the front and rear plate surfaces of the shell is C, C≥1.5B, and the upper ends of the front curved surface, the left curved surface, the rear curved surface and the volute tongue surface are in the shape of four non-concentric arcs.

[0015] Preferably, the volute tongue surface is a concave surface near the outlet of the volute, and the volute tongue surface is a flat surface near the starting point of the volute.

[0016] Preferably, the plane of the volute tongue surface is arranged at an angle to the output shaft and is not perpendicular.

[0017] Preferably, the angle between the plane of the volute tongue surface and the axial direction of the output shaft is 12°-16°.

[0018] Preferably, the fan further comprises an air outlet section, the inlet of the air outlet section is connected to the outlet of the transition section, the inlet shape of the air outlet section is the same as the outlet shape of the transition section, and the outlet shape of the air outlet section is circular.

[0019] On the other hand, the present invention provides a range hood, comprising a housing and a fan as described in any of the above technical solutions.

[0020] The beneficial effects of the present invention are:

[0021] The present invention provides a fan, i.e., a range hood, which includes a volute, a power member, and an impeller, wherein the power member is arranged in the volute, the impeller is connected to the output end of the power member by transmission, and the blades of the impeller are arranged at an angle with the axial direction of the output shaft of the power member along the width direction of the volute and are not perpendicular. The above arrangement allows the circumferential non-uniform airflow flowing out of the blades to be dispersed on the volute tongue surface in a direction perpendicular to the output shaft, that is, the pulse airflow acting on the volute tongue surface is phase-shifted, thereby reducing the pulse force generated on the volute tongue surface, and greatly reducing the noise of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a range hood in an embodiment of the present invention;

[0023] Figure 2 It is a structural schematic diagram of a fan in an embodiment of the present invention;

[0024] Figure 3 Schematic diagram of the exploded structure of the fan in the embodiment of the present invention;

[0025] Figure 4 Schematic diagram of the spiral structure forming the volute in an embodiment of the present invention;

[0026] Figure 5 It is a schematic diagram of the structure of the transition section in an embodiment of the present invention;

[0027] Figure 6 is a schematic diagram of the structure of a blade in an embodiment of the present invention;

[0028] Figure 7 It is a schematic diagram of the top view of the transition section in an embodiment of the present invention;

[0029] Figure 8 Schematic diagram of the structure of the tongue surface of the snail from the first perspective in an embodiment of the present invention;

[0030] Fig. 9 2 is a schematic diagram of the structure of the tongue surface of the snail from a second viewing angle in an embodiment of the present invention;

[0031] Fig.10 Schematic diagram of the top view of the fan in an embodiment of the present invention;

[0032] Fig.11 It is a schematic diagram of the side structure of the fan in an embodiment of the present invention;

[0033] Fig.12 It is a schematic diagram of the main structure of the fan in an embodiment of the present invention.

[0034] In the figure:

[0035] 100, housing; 200, power part; 300, impeller; 301, blades;

[0036] 1. Volute front plate; 2. Volute rear plate; 3. Volute side plate;

[0037] S1, first volute curve; S2, second volute curve; L1, volute straight line; S3, third volute curve; S4, fourth volute curve; S5, transition outer contour arc; S6, first outer contour arc; S7, second outer contour arc; S8, volute tongue contour arc;

[0038] 4. Transition section; 41. Front curved surface; 411. Front first surface; 412. Front second surface; 413. Front third surface; 42. Left curved surface; 43. Back curved surface; 44. Snail tongue surface;

[0039] 5. Air outlet section; 51. First curved surface; 52. Second curved surface; 53. Third curved surface; 54. Fourth curved surface; 501. Curve cluster. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0044] Embodiment 1

[0045] like Figure 1-12As shown, this embodiment provides a volute, which includes a volute rear plate 2, a volute front plate 1 and a volute side plate 3, and the volute side plate 3 is connected between the volute rear plate 2 and the volute front plate 1. The inner side wall of the volute side plate 3 is formed by sequentially connecting the first volute curve S1, the second volute curve S2, the volute straight line L1, the third volute curve S3, and the fourth volute curve S4. The opening degree of the volute at the first volute curve S1, the second volute curve S2, the third volute curve S3 and the fourth volute curve S4 gradually increases along the outlet direction, the volute straight line L1 is a horizontal line at the bottom of the volute, and the opening degree of the volute at the volute straight line L1 remains unchanged along the outlet direction. In the above-mentioned volute, since the volute curve gradually increases along the outlet direction of the volute as a whole, the opening of the volute at the bottom of the volute is already much larger than the outer diameter of the impeller 300, and only setting the volute straight line L1 at the bottom of the volute will not affect the outer diameter of the impeller 300. Therefore, the above-mentioned setting does not need to reduce the outer diameter of the impeller 300 on the basis of reducing the height H of the entire volute, and the volute will not cause the power of the impeller 300 to be reduced on the basis of adapting to the housing 100 with a slightly smaller height. Compared with the solution in the prior art of reducing the outer diameter of the impeller 300 by reducing the overall size of the volute, the setting of this embodiment helps to increase the power of the impeller 300 when the speed is the same, and helps to reduce noise when the power is the same.

[0046] Regarding the specific structure of the first volute curve S1, optionally, the first volute curve S1 is given by equation Determine; wherein the angle range of the first volute curve S1 is 38° to 205°, D is the outer diameter of the impeller 300, e is the base of a natural number, t1 is the curve control parameter, and 0<t1≤0.1, is the angle between the line connecting the point on the first volute curve S1 and the center of the circle O and the starting ray. The above equation is simpler and the adjustment is more flexible and convenient.

[0047] Regarding the specific structure of the fourth volute curve S4, optionally, the fourth volute curve S4 is given by equation Determine; wherein the angle range of the fourth volute curve S4 is 265° to 360°, D is the outer diameter of the impeller 300, e is the base of a natural number, t2 is the curve control parameter, and 0<t2≤0.1, is the angle between the line connecting the point on the second volute curve S2 and the center of the circle O and the starting ray. The above equation is simpler and the adjustment is more flexible and convenient.

[0048] Regarding the opening degree of the volute at various locations, in this embodiment, as a preference, the opening degree of the volute at the first volute curve S1 is The opening degree of the volute at the fourth volute curve S4 is Wherein, t2≥t1. Preferably, t1 is t1=0.0439, and t2 is t1=0.0445. Of course, in other embodiments, t1 and t2 can be other values, specifically, they can be determined according to the height size of the housing 100. The above setting can realize the widening of the spiral line of the volute near the outlet side, thereby increasing the exhaust passage area. The coordination of the above equations can realize the change of the opening degree of the volute on the one hand, and divide the spiral line of the volute into five, so as to realize segmented control and make it easier to adjust; it helps the first volute curve S1 to be perpendicular to the line connecting the point and the center of the circle 0 at 205 degrees, and helps the fourth volute curve S4 to be perpendicular to the line connecting the point and the center of the circle 0 at 265 degrees, which is convenient for drawing the second volute curve S2 and the third volute curve S3, and is conducive to realizing that the second volute curve S2 and the third volute curve S3 are tangent to the first volute curve S1 and the fourth volute curve S4 respectively, thereby reducing the overall mutation.

[0049] To achieve smooth connection of the volute, in this embodiment, preferably, the second volute curve S2 is an arc, and its two ends are tangent to the first volute curve S1 and the volute straight line L1 respectively. The third volute curve S3 is an arc, and its two ends are tangent to the fourth volute curve S4 and the volute straight line L1 respectively. Of course, in other embodiments, an elliptical arc can be used for connection, which is not limited to this.

[0050] Embodiment 2

[0051] This embodiment also provides a fan, comprising a transition section 4 and a volute in any of the above embodiments, wherein the transition section 4 is disposed at the outlet of the volute. A power part 200 and an impeller 300 are also disposed in the volute of the fan, wherein the power part 200 is preferably a motor, wherein the impeller 300 is drivingly connected to the output end of the motor fixed to the housing 100. With the structure of the volute, the fan can adapt to a housing 100 with a slightly lower height, without reducing the working efficiency of the impeller 300 and without increasing the noise in the air duct.

[0052] Specifically, the transition section 4 includes a front curved surface 41, a left curved surface 42, a rear curved surface 43 and a volute tongue surface 44 which are connected in sequence. The lower ends of the front curved surface 41, the left curved surface 42, the rear curved surface 43 and the volute tongue surface 44 are all straight lines. The front curved surface 41 and the rear curved surface 43 are respectively used to connect with the volute front plate 1 and the volute rear plate 2; the volute tongue surface 44 and the left curved surface 42 are respectively used to connect with the starting end and the end of the volute side plate 3; and / or

[0053] The volute tongue surface 44 of the transition section 4 is located in the housing 100, the distance between the volute front plate 1 and the volute rear plate 2 is B, the distance between the front and rear plates of the housing 100 is C, C ≥ 1.5B, the front curved surface 41, the left curved surface 42, the rear curved surface 43 and the upper end of the volute tongue surface 44 are in the shape of four non-concentric arcs. Among them, 90mm ≤ B ≤ 120mm, C = 180mm. Due to the height restriction of the housing 100, the smooth transition between the width dimension at the outlet of the volute and the diameter dimension of the outlet of the transition section 4 is ensured. In order to avoid sudden changes caused by the flow channel, the transition section 4 cannot transition to a circle in the housing 100.

[0054] The maximum distance W1 between the two arcs at the upper ends of the front curved surface 41 and the rear curved surface 43 is ≥ the opening degree A2 of the fourth volute curve S4 at the 360° position, In this example, t2 = 0.0445, The curvature of the left curved surface 42 extends along the volute side plate 3 formed by the fourth volute curve S4, and the maximum distance W2 between the arc formed by the upper end of the left curved surface 42 and the arc formed by the upper end of the volute tongue surface 44 is close to W1. The purpose of this transition end is to transition the quadrilateral at the end section of the volute side to an arc connection structure that is approximately circular, and to ensure that the size of the diffuser section is close to prevent sudden loss.

[0055] The volute tongue surface 44 is formed based on a Bezier curve. The volute tongue surface 44 is a concave structure near the outlet of the volute, and a flat structure near the starting point of the volute. The outlet of the volute is at 360°, that is, 0°, and the starting point of the volute is at 38°. The upper and lower parts of the volute tongue surface 44 at the concave structure are closer to the impeller 300, which helps to improve the outlet static pressure and fan efficiency. The air flow velocity at the middle part of the impeller 300 is relatively large, and the concave structure can reduce flow resistance and eliminate outlet vortex.

[0056] Specifically, the two-dimensional curve line equation of the volute tongue surface 44 is as follows:

[0057]

[0058] This expression can be expressed as an n-order Bezier curve, where P is the coordinate of the control point and n is the number of control points. The Bezier curve can change the shape of the curve by changing the position of the control point. This curve generation method is more intuitive and flexible, and can generate any curve shape.

[0059] The first column number: n = 4, P0 = 28.5, P1 = 43.4, P2 = 47.6, P3 = 51.7, P4 = 42.8, that is

[0060]

[0061] The second column number: n = 4, P0 = 151.6, P1 = 146.0, P2 = 144.7, P3 = 154.4, P4 = 167.9, that is:

[0062]

[0063] The first column represents the coordinates of all X-axis vectors on the curve, and t is an arbitrary number in the range of 0 to 1. The second column represents the coordinates of all Y-axis vectors on the curve, and t is an arbitrary number in the range of 0 to 1. The positions of all points on the spline curve can be represented by B1(t) and B2(t), which determines the shape and size parameters of the curve.

[0064] In this embodiment, the impeller 300 includes blades 301 and an output shaft, and the blades 301 are arranged at an angle with the output shaft along the width direction of the volute and are not perpendicular. Figure 2 As shown, the width direction of the volute is the direction from the volute front plate 1 to the volute rear plate 2 or from the volute rear plate 2 to the volute front plate 1. The angle θ can be any degree between 12° and 16°. This setting allows the circumferential non-uniform airflow flowing out of the blade 301 to be dispersed on the volute tongue surface 44 in a direction perpendicular to the output shaft, that is, the pulse airflow acting on the volute tongue surface 44 is phase-shifted, thereby reducing the pulse force generated on the volute tongue surface 44, and greatly reducing the noise of the fan.

[0065] Preferably, the blade 301 is inclined to the transition section 4 along the direction from the volute rear plate 2 to the volute front plate 1. This arrangement is conducive to conveying the airflow to the volute front plate 1, thereby adapting to the structure in which the outlet end of the transition section 4 is located in front of the volute rear plate 2.

[0066] Optionally, the plane at the lower end of the volute tongue surface 44 is set at an angle to the output shaft. The above setting can disperse the airflow flowing out of the blade 301 on the volute tongue surface 44 along the axial direction of the output shaft, further reducing the pulse force generated on the volute tongue surface 44, thereby further reducing the noise of the range hood. Optionally, the angle between the straight line at the lower end of the volute tongue surface 44 and the output shaft is the same as the angle between the blade 301 and the shaft. That is, the angle between the plane of the volute tongue surface 44 and the axial direction of the output shaft is 12°-16°.

[0067] Regarding the setting of the transition section 4, in this embodiment, the front curved surface 41 partially protrudes forward from the volute front plate 1, and the horizontal distance between the arc formed at the upper end of the front curved surface 41 and the volute front plate 1 is greater than 0, and the rear curved surface 43 partially protrudes forward from the volute rear plate 2, and the horizontal distance between the arc formed at the upper end of the rear curved surface 43 and the volute rear plate 2 is greater than or equal to 0; the left curved surface 42 and the volute tongue surface 44 are both inclined in the direction toward the volute front plate 1. The above structure makes the projection of the outlet of the transition section 4 on the horizontal plane located in front of the projection of the volute rear plate 2 on the horizontal plane. Then, the range hood equipped with the volute is installed behind the wall, and the transition section 4 does not interfere with the wall.

[0068] Specifically, the front curved surface 41 includes a front first surface 411, a front second surface 412 and a front third surface 413 connected in sequence from left to right, wherein the front first surface 411 protrudes forward from the volute front plate 1, and the horizontal distance between the arc formed by the upper end of the front first surface 411 and the volute front plate 1 is greater than 0, and the rear curved surface 43 includes a rear first surface, a rear second surface and a rear third surface connected in sequence from left to right, wherein the rear first surface protrudes forward from the volute rear plate 2, and the horizontal distance between the arc formed by the upper end of the rear first surface and the volute rear plate 2 is greater than 0. The lower ends of the front second surface and the rear second surface are respectively connected to the ends of the volute front plate 1 and the volute rear plate 2 near the volute side plate 3; the upper ends of the front second surface and the rear second surface are respectively connected to the front and rear sides of the volute tongue surface 44; the upper ends of the front third surface and the rear third surface are respectively connected to the initial ends of the volute front plate 1 and the volute rear plate 2 near the volute side plate 3.

[0069] After the oil smoke comes out of the transition section 4, it needs to continue to be transmitted. In this embodiment, preferably, the fan also includes an air outlet section 5. The air outlet section 5 has an inlet connected to the outlet of the transition section 4. The inlet shape of the air outlet section 5 is the same as the outlet shape of the transition section 4, and the outlet shape of the air outlet section 5 is circular. Specifically, the air outlet section 5 includes a first curved surface 51, a second curved surface 52, a third curved surface 53 and a fourth curved surface 54 connected in sequence. The first curved surface 51, the second curved surface 52, the third curved surface 53 and the fourth curved surface 54 are four non-concentric arcs at the lower end of the air outlet section 5, and the first curved surface 51, the second curved surface 52, the third curved surface 53 and the fourth curved surface 54 are four concentric arcs at the upper end of the air outlet section 5. In this setting, the air outlet section 5 smoothly transitions from the inlet to the outlet to a circle, can smoothly access the circular smoke exhaust pipe, reduce the flow resistance, and reduce the loss of the air flow in the volute due to the sudden change of curvature.

[0070] Among them, preferably, the smooth transition of the air outlet section 5 from the inlet to the outlet is achieved by controlling the curve cluster 501. In computer graphics, the dimensional relationship in the surface space cannot be controlled by constructing a spline surface only by the edge line. The curve cluster 501 is a series of arcs. According to a certain contour control line, a spatial curve cluster 501 with uniform density and gradual transition is formed in space. The spatial curve cluster 501 is scanned through the surface to form a smoothly transitioned and full flow channel space.

[0071] The first outer contour arc S6 of the curve cluster 501 is an inward-concave circular arc, which is smoothly connected to the transition outer contour arc S5 of the transition section 4, thereby suppressing premature flow separation of the airflow, slowing down and pressurizing the outlet airflow of the air outlet section 5, suppressing premature flow separation of the gas from the wall of the air outlet section 5, and reducing aerodynamic noise.

[0072] The second outer contour arc S7 of the curve cluster 501 is an outward convex arc line, which is smoothly connected to the volute tongue contour arc S8 of the volute tongue surface 44, and plays a role in gathering the airflow.

[0073] Based on the combined effect of the first outer contour arc S6 and the second outer contour arc S7, the airflow transition can be smooth, released first and then collected, the airflow separation noise can be reduced, and the sudden loss of a large shape can be avoided. The outlet airflow of the air outlet section 5 can be evenly distributed, solving the problem of large-scale eddies and flow dead zones in the outlet area of ​​the air outlet section 5.

[0074] Optionally, the distance between the circular circle O at the upper end of the air outlet section 5 and the bottom plate of the volute is L2, the distance between the volute front plate 1 and the volute rear plate 2 is B, and B / 2<L2<B. This setting can ensure that the range hood equipped with the volute is installed behind the wall without interference between the air outlet section 5 and the wall.

[0075] Embodiment 3

[0076] This embodiment further provides a range hood, including a housing 100 and a fan disposed in the housing 100 , wherein the fan is disposed inside the housing 100 .

[0077] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A fan, characterized in that: include: snail shell; A power member (200), wherein the power member (200) is disposed in the volute; An impeller (300), the impeller (300) being drivingly connected to the output end of the power member (200), and the blades (301) of the impeller (300) are arranged at an angle along the width direction of the volute to the axial direction of the output shaft of the power member (200) and are not perpendicular; The fan further comprises a transition section (4), wherein the transition section (4) is arranged at the outlet of the volute; The volute comprises a volute front plate (1), a volute rear plate (2) and a volute side plate (3), wherein the volute side plate (3) is connected between the volute rear plate (2) and the volute front plate (1); the blade (301) is inclined at the transition section (4) along the direction from the volute rear plate (2) to the volute front plate (1); The outlet end of the transition section (4) is located in front of the volute rear plate (2); The transition section (4) comprises a front curved surface (41), a left curved surface (42), a rear curved surface (43) and a volute tongue surface (44) which are connected in sequence. The lower ends of the front curved surface (41), the left curved surface (42), the rear curved surface (43) and the volute tongue surface (44) are all in a straight line shape. The front curved surface (41) and the rear curved surface (43) are respectively used to connect to the volute front plate (1) and the volute rear plate (2). The volute tongue surface (44) and the left curved surface (42) are respectively Used to connect with the starting end and the end of the volute side plate (3); the volute tongue surface (44) of the transition section (4) is located in the outer shell (100), the distance between the volute front plate (1) and the volute rear plate (2) is B, the distance between the front and rear plate surfaces of the outer shell (100) is C, C ≥ 1.5B, and the upper ends of the front curved surface (41), the left curved surface (42), the rear curved surface (43) and the volute tongue surface (44) are in the shape of four non-concentric arcs; The front curved surface (41) partially protrudes forward from the volute front plate (1), and the horizontal distance between the arc formed by the upper end of the front curved surface (41) and the volute front plate (1) is greater than 0. The rear curved surface (43) partially protrudes forward from the volute rear plate (2), and the horizontal distance between the arc formed by the upper end of the rear curved surface (43) and the volute rear plate (2) is greater than 0.

2. The fan according to claim 1, characterized in that: The included angle between the blade (301) and the axial direction of the output shaft of the power component (200) is 12°-16°.

3. The fan according to claim 1, characterized in that: The volute tongue surface (44) is a concave surface near the outlet of the volute, and the volute tongue surface (44) is a flat surface near the starting point of the volute.

4. The fan according to claim 3, characterized in that: The plane of the volute tongue surface (44) is arranged at an angle with the output shaft and is not perpendicular.

5. The fan according to claim 4, characterized in that: The angle between the plane of the volute tongue surface (44) and the axial direction of the output shaft is 12°-16°.

6. The fan according to claim 1, characterized in that: The fan further comprises an air outlet section (5), the inlet of the air outlet section (5) being connected to the outlet of the transition section (4), the inlet shape of the air outlet section (5) being the same as the outlet shape of the transition section (4), and the outlet shape of the air outlet section (5) being circular.

7. A range hood, comprising a housing (100), characterized in that: It also includes the fan according to any one of claims 1-6.

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