CN114483653A - Volute, centrifugal fan and range hood - Google Patents

Abstract

The application relates to the technical field of range hoods, and the embodiment of the application provides a volute, a centrifugal fan and a range hood. The molded line of the volute comprises a first molded line segment, a second molded line segment, a third molded line segment and a fourth molded line segment which are connected in sequence, and the two connected molded line segments are in smooth transition. The third molded line section forms a main body of the volute, the second molded line section forms a volute tongue of the volute, and the third molded line section is located on the logarithmic spiral curve. The logarithmic spiral curve where the third molded line segment is located is an arc line segment generated by the same circle center, the curvature of the third molded line segment is continuous, and meanwhile, the radial clearance between the logarithmic spiral curve and the reference circle is gradually increased by designing the reference circle, so that the change of the polar radius of the third molded line segment is continuous, the molded line error of the volute is reduced, vortex can be prevented from being generated in the volute to reduce the noise of the volute, gas in the volute can be concentrated, and the smoke exhaust efficiency of the volute is improved.

Description

Volutes, centrifugal fans and range hoods

technical field

The present application relates to the technical field of range hoods, in particular to a volute, a centrifugal fan and a range hood.

Background technique

In the related art, the volute profile design mostly uses four arcs with different centers to generate the volute profile. In this process, since the arc radius is positively related to the impeller speed, the greater the speed of the impeller, the greater the error of the volute profile. In this way, the profile line of the volute does not match the impeller, resulting in low smoke exhaust efficiency and high noise of the volute. At the same time, in the method of generating the volute profile, the arc radius of the adjacent arcs changes greatly, which will cause vortexes to be generated in the volute, so that the air volume, wind pressure and efficiency of the fan will be greatly reduced, and the volute will be greatly reduced. Large pressure gradients develop in the shell, resulting in increased vortex noise.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a volute, a centrifugal fan and a range hood to improve the smoke exhaust efficiency of the volute and reduce the noise of the volute in view of the above technical problems.

According to one aspect of the present application, an embodiment of the present application provides a volute, and the profile of the volute includes a first profile segment, a second profile segment, a third profile segment, and a fourth profile segment connected in sequence. The smooth transition between the two profile segments; the third profile segment constitutes the main body of the volute, the second profile segment constitutes the volute tongue of the volute, the first profile segment and the fourth profile segment The profile segment constitutes the air outlet of the volute, and the third profile segment is located on the logarithmic spiral curve;

The third-type line segment and the second-type line segment are tangent to the first tangent point, the third-type line segment and the fourth-type line segment are tangent to the second tangent point, and from the first tangent point along the The direction from the third type line segment to the second tangent point is the first path direction; define a circle with the pole of the logarithmic spiral curve as the center and the radius r of the impeller located in the volute as the radius is a reference circle, the logarithmic spiral curve intersects with the reference circle at a first intersection point, and the contour of the reference circle is located between the first intersection point and the second tangent point of the logarithmic spiral curve A radial gap is constructed between;

Wherein, in the direction of the first path, the radial gap gradually increases, and the curvature of the third-shaped line segment is continuous.

In the above volute, since the logarithmic spiral curve where the third-shaped line segment is located is an arc segment generated by the same circle center, the curvature of the third-shaped line segment is continuous. At the same time, by designing the reference circle, the logarithmic spiral curve and the reference circle are constructed. The radial gap between them gradually increases, so that the change of the pole radius of the third profile line segment is continuous, which reduces the error of the volute profile, not only can prevent the eddy current from being generated in the volute to reduce the noise of the volute, It can also make the gas in the volute more concentrated, and improve the smoke exhaust efficiency of the volute.

In one of the embodiments, the line connecting the pole and the first tangent point and the outline of the reference circle intersect at a second intersection point, and the line connecting the second intersection point and the first tangent point intersects at a second intersection point. The length is d1; wherein, the ratio of r to d1 is 5.73-8.8. In this way, the distance between the third-shaped line segment and the reference circle can be defined, that is, the minimum distance between the volute tongue of the volute and the matched impeller, that is, between the volute and the matched impeller The minimum distance to prevent wind noise at the volute tongue due to fluid shunting, and prevent wind noise from being transmitted to the outside through the volute tongue and affecting the user's experience of use.

In one of the embodiments, the second-shaped line segment is an arc. In this way, the wind resistance at the volute tongue can be reduced by the arc shape.

In one of the embodiments, the arc radius of the second shaped line segment is R; wherein, the ratio of r to R is 7.33-10.15. In this way, the size of the arc radius of the second-shaped line segment can be limited, that is, the size of the corner of the volute tongue can be limited, and the wind noise at the volute tongue can be further reduced.

In one embodiment, a line connecting the pole of the logarithmic spiral curve and the arc center of the second-shaped line segment is a first connecting line, and the connecting line between the pole and the first intersection point and the first connecting line The included angle of a connecting line is α1; among them, 76°≤α1≤86°. In this way, the arc length of the second-shaped line segment can be defined, and the volute tongue with a preset shape can be constructed to further improve the dynamic characteristics of the fluid flowing through the volute tongue.

In one embodiment, the fourth-shaped line segment is a straight line, and the included angle between the fourth-shaped line segment and the line connecting the pole and the second intersection is α2; wherein, 80°≤α2≤90 °. In this way, a reasonable expansion angle of the volute can be obtained, the gas inside the volute is prevented from flowing back into the volute, and the exhaust efficiency is improved.

In one embodiment, the length of the line connecting the first intersection point and the second tangent point is d2; wherein, the ratio of r to d2 is 1.38-1.56. In this way, the third-shaped line segment can be limited, and further the curvature of the third-shaped line segment can be limited, which further reduces the error of the volute molding line.

In one embodiment, the equation of the logarithmic spiral curve is:

为所述对数螺旋曲线的极半径与所述极点和所述第一交点的连线的夹角，

为R的修正值。如此，通过设置修正值，对螺旋曲线进行修正，可以降低蜗壳型线的误差。Wherein, r is the radius of the impeller, e is the base of the natural logarithm, a is the back flow angle of the blade of the impeller, b is the outlet width of the impeller, B is the height of the volute,

is the angle between the pole radius of the logarithmic spiral curve and the line connecting the pole and the first intersection,

is the corrected value of R. In this way, by setting the correction value to correct the helical curve, the error of the volute profile can be reduced.

In one embodiment, the maximum rotational speed of the impeller is 800r/min-1000r/min, and l is 10mm-15mm;

The maximum rotational speed of the impeller is 600r/min-800r/min, and l is 5mm-10mm. In this way, different degrees of correction can be made according to the impellers of different rotational speeds.

According to another aspect of the present application, an embodiment of the present application provides a centrifugal fan, comprising an impeller and the above-mentioned volute;

Wherein, the impeller is arranged in the volute, and the center of the impeller coincides with the pole of the logarithmic spiral curve. In this way, the centrifugal fan can have high smoke exhaust efficiency and low noise.

In one embodiment, the number of blades of the impeller ranges from 64 blades to 70 blades. In this way, the profile of the volute and the impeller can be more matched, the smoke exhaust efficiency of the volute is improved, and the noise is reduced.

According to another aspect of the present application, an embodiment of the present application provides a range hood, including the centrifugal fan described above. In this way, the smoke exhausting efficiency of the range hood can be high and the noise is low.

Additional aspects and advantages of embodiments of the present application will be set forth, in part, in the following description, and in part will be apparent from the following description, or learned by practice of embodiments of the present application.

Description of drawings

1 is a schematic diagram of a volute profile in an embodiment of the related art;

2 is a schematic diagram of a volute profile in another embodiment of the related art;

3 is a schematic structural diagram of a volute in an embodiment of the application;

4 is a schematic cross-sectional structural diagram of a volute in an embodiment of the application;

5 is a schematic diagram of a volute profile in an embodiment of the application;

Fig. 6 is the partial enlarged schematic diagram of the second type line segment in Fig. 5 of the application;

7 is a schematic structural diagram of a volute profile in an embodiment of the application;

8 is a schematic diagram of a sound pressure cloud diagram of a volute provided in an embodiment of the application;

9 is a schematic diagram of a sound pressure cloud diagram of a volute provided in another embodiment of the application;

FIG. 10 is a schematic diagram of a sound pressure cloud diagram of a volute provided in another embodiment of the present application.

Simple description of component symbols:

a first-type line segment L1, a second-type line segment L2, a third-type line segment L3, a fourth-type line segment L4, a first connecting line L5, and a second connecting line L6;

Pole O, reference circle P, radial clearance t;

The first tangent point T1, the second tangent point T2, and the third tangent point T3;

The first intersection point C1, the second intersection point C2;

The volute tongue 100, the air outlet 200, the volute upper plate 300, the volute bottom plate 400, the volute surrounding plate 500, the air inlet 600, and the air guide ring 700;

Impeller 20;

Motor 30.

Detailed ways

In order to make the above objects, features and advantages of the present application more clearly understood, the specific implementations of the embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to facilitate a thorough understanding of the embodiments of the present application. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. The embodiments of 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 invention. Therefore, the embodiments of the present application are not subject to the specific embodiments disclosed below. limits.

It can be understood that the terms "first", "second", "third", "fourth", etc. used in this application can be used to describe various technical terms in this document, and cannot be understood as indicating or implying relative importance. nature or implicitly indicate the number of technical features indicated. However, unless otherwise specified, these professional terms are not limited by these terms. These terms are only used to distinguish one professional term from another. For example, without departing from the scope of the present application, the first type line segment, the second type line segment, the third type line segment and the fourth type line segment are different type line segments, the first tangent point, the second tangent point and the The third tangent point is a different tangent point. In the description of the embodiments of the present application, "plurality" and "several" mean at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the description of the embodiments of the present application, unless otherwise expressly specified and limited, terms such as "installation", "connection", "connection", and "fixation" should be understood in a broad sense. For example, it may be a fixed connection or a It can be 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, it can be the internal connection of two elements or the interaction relationship between the two elements, unless otherwise expressly qualified. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present application according to specific situations.

In the description of the embodiments of the present application, unless otherwise expressly specified and limited, the first feature "on" or "under" the second feature may be in direct contact with the first and second features, or the first and second features Indirect contact through an intermediary. Also, the first feature is "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the level of the first feature is higher than the level of the second feature . The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly or diagonally below the second feature, or simply means that the first feature level is less than the second feature level.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or an intervening element may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in this application in the specification of this application are for the purpose of describing specific embodiments only, and are not intended to limit the application.

The centrifugal volute is one of the core components of the range hood, which can concentrate the gas near the air inlet of the volute, and drive the impeller to rotate through the drive motor, thereby discharging the gas from the outlet of the volute. In this process, the profile of the centrifugal volute not only determines the shape of the volute, but also affects the air volume, air pressure, efficiency and noise of the entire range hood.

Fig. 1 shows a schematic diagram of a volute profile in an embodiment of the related art; Fig. 2 shows a schematic diagram of a volute profile in another embodiment of the related art; Example relevant part.

Referring to FIG. 1 and FIG. 2 , in the related art, the volute profile is composed of multiple arcs, and four arcs with different centers are often used to generate the volute profile. Therefore, this segment of the curve has four arc radii of R1, R2, R3 and R4. The inventor of the present application has noticed that the arc radius of the adjacent arcs varies greatly, which will cause vortices to be generated in the volute, and the air volume, air pressure and efficiency of the fan will be greatly reduced, and a large vortex will be formed in the volute. pressure gradient, resulting in increased vortex noise. In addition, since the arc radius is positively related to the impeller speed, the greater the speed of the impeller, the greater the error of the volute profile. In this way, the profile line of the volute does not match the impeller, resulting in low smoke exhaust efficiency and high noise of the volute.

Based on the above considerations, the inventor has designed a volute after in-depth research. By defining the shape of the volute profile, the smoke exhaust efficiency of the volute can be improved and the noise of the volute can be reduced. The volute provided by the embodiments of the present application will be described below with reference to the relevant descriptions of some embodiments.

The volute disclosed in the embodiments of the present application can be used in a centrifugal fan, the centrifugal fan can be used in a range hood, and can also be used in other wind power systems that need to use the air duct structure formed by the volute. The following description takes the specific structure of the volute in some embodiments as an example, but it is not limited thereto. It should be noted that, the molding line of the volute disclosed in the embodiment of the present application may be clockwise or counterclockwise, which may be selected according to the usage, which is not specifically limited in the embodiment of the present application.

Fig. 3 shows a schematic structural diagram of a volute in an embodiment of the present application; Fig. 4 shows a cross-sectional structural schematic diagram of a volute in an embodiment of the present application; relevant part.

For ease of understanding, as shown in Figure 4, the top of the drawing is defined as the upper side, the lower side of the drawing is defined as the bottom, the left side of the drawing is defined as the left side, the right side of the drawing is defined as the right side, and the drawing is defined as the right side. The left side is defined as the front side, and the right side of the drawing is defined as the back side. The rest of the illustrations follow the definition in Figure 4. It can be understood that the above definitions are only for illustration, and should not be construed as limitations on the present application. It can be understood that the above definitions are only for illustration, and should not be construed as limitations on the present application.

Referring to FIGS. 3 and 4 , an embodiment of the present application provides a volute, the volute includes a volute upper plate 300 , a volute bottom plate 400 and a volute surrounding plate 500 . An air inlet 600 is provided on the upper plate 300 of the volute. The volute bottom plate 400 is spaced apart from the volute upper plate 300 , and the volute bottom plate 400 is provided with a mounting hole for mounting the motor 30 . The volute casing 500 is connected between the volute upper plate 300 and the volute bottom plate 400, and the volute casing 500, the volute upper plate 300 and the volute bottom plate 400 enclose an accommodation space and an air outlet 200 on the rear side , the air inlet 600, the installation hole (marked in the figure) and the air outlet 200 communicate with the accommodating space. The accommodating space is used to accommodate the impeller 20 . A volute tongue 100 is formed on the side of the volute enclosure plate 500 close to the air outlet 200 . The function of the volute tongue 100 is to divide the airflow at the outlet of the volute. The flow field at the volute tongue 100 is relatively complex, and the volute tongue 100 is also the place where the centrifugal volute noise is generated.

The shape of the volute is described below by taking the structure of the volute in some of the above embodiments as an example.

Fig. 5 shows a schematic diagram of a volute profile in an embodiment of the present application; Fig. 6 shows a partially enlarged schematic diagram of the second profile line segment L2 in Fig. 5 of the present application; Relevant parts in the examples.

Referring to FIGS. 5 and 6, an embodiment of the present application provides a volute, and the profile of the volute includes a first profile segment L1, a second profile segment L2, a third profile segment L3, and a fourth profile segment connected in sequence L4. Smooth transition between two connected line segments. The third-shaped line segment L3 constitutes the main body of the volute, the second-shaped line segment L2 constitutes the volute tongue 100 of the volute, the first-shaped line segment L1 and the fourth-shaped line segment L4 constitute the air outlet 200 of the volute, and the third-shaped line segment L3 is located on the opposite side of the volute. number on the spiral curve.

The third-type line segment L3 and the second-type line segment L2 are tangent to the first tangent point T1, and the third-type line segment L3 and the fourth-type line segment L4 are tangent to the second tangent point T2. From the first tangent point T1 along the third The direction from the profile line segment L3 to the second tangent point T2 is the first path direction; the circle obtained by taking the pole O of the logarithmic spiral curve as the center and the radius r of the impeller 20 located in the volute as the radius is the reference circle P, and the logarithm The helical curve intersects the reference circle P at the first intersection point C1, and a radial gap t is formed between the contour of the reference circle P and the logarithmic helical curve located between the first intersection point C1 and the second tangent point T2. Wherein, in the first path direction, the radial gap t gradually increases, and the curvature of the third-shaped line segment L3 is continuous. That is, the difference between the pole radius of the logarithmic spiral curve and the radius of the impeller 20 gradually increases in the first path direction. Taking FIG. 5 as an example, the first path direction is a clockwise direction along the third-shaped line segment L3.

It should be noted that "the main body of the volute" refers to the part of the impeller 20 corresponding to the volute enclosure plate 500 after the impeller 20 is placed in the volute case, and the volute enclosure plate 500 is bent to fit the impeller 20 Correspondingly, the shape of the volute upper plate 300 and the volute bottom plate 400 in this part is also adapted to the volute surrounding plate 500 . The "radial clearance t" starts from zero at the first intersection point C1 and ends at the position corresponding to the second tangent point T2.

Since the logarithmic spiral curve where the third-type line segment L3 is located is an arc segment generated by the same circle center, the curvature of the third-type line segment is continuous. At the same time, by designing the reference circle P, the logarithmic spiral curve and the reference circle P are constructed The radial gap t gradually increases, so that the change of the pole radius of the third type line segment L3 is continuous. That is to say, the radial gap t and the curvature of the third-type line segment L3 constrain the structure of the third-type line segment L3, so that the third-type line segment L3 is more stable and smooth, and the change of the polar radius of the third-type line segment L3 is continuous. , reducing the error of the volute shape line, not only can prevent the vortex from being generated in the volute to reduce the noise of the volute, but also make the gas in the volute more concentrated and improve the smoke exhaust efficiency of the volute.

In some embodiments, please continue to refer to FIG. 5 and FIG. 6 , the line between the pole O and the first tangent point T1 intersects the outline of the reference circle P at the second intersection point C2 , and the second intersection point C2 and the first tangent point The length of the T1 connection is d1. Among them, the ratio of r to d1 is 5.73-8.8. In this way, the distance between the third-shaped line segment L3 and the reference circle P can be defined, that is, the minimum distance between the volute tongue 100 of the volute and the impeller 20 used in the volute, that is, the volute and the supporting impeller 20 can be defined. The minimum distance between the impellers 20. The volute tongue 100 can prevent part of the gas from circulating in the volute. When the air flow at the outlet of the blade passage of the impeller 20 passes near the volute tongue 100 , the volute tongue 100 divides the air flow, and most of the air flow flows to the air outlet 200 along the passage. A small part of the airflow flows back into the volute through the gap between the volute tongue 100 and the impeller 20, and returns to the volute tongue 100 after rotating with the impeller 20 for one week in the volute to participate in a new branch flow. If the gap between the volute tongue 100 and the impeller 20 is too small, although the air flow in the backflow volute will be less, the air flow towards the air outlet 200 will increase, and the wind noise will increase. When the gap between the volute tongue 100 and the impeller 20 is too large, the air flow to the air outlet 200 will decrease, and the air flow back into the volute will increase, resulting in low exhaust efficiency of the volute. In this way, by defining the minimum distance between the volute tongue 100 of the volute and the impeller 20 used therewith, not only can the volute tongue 100 be prevented from generating wind noise due to fluid shunting, but also the wind noise can be prevented from being transmitted to the outside through the volute tongue 100 . Affect the user's experience, but also can get good exhaust efficiency.

In some embodiments, please continue to refer to FIG. 5 and FIG. 6 , the second type line segment L2 is an arc. In this way, the wind resistance at the volute tongue 100 can be reduced by the arc shape. Specifically, in some embodiments, the arc radius of the second-shaped line segment L2 is R; wherein, the ratio of r to R is 7.33-10.15. In this way, the size of the arc radius R of the second type line segment L2 can be limited, that is, the size of the corner of the volute tongue 100 can be limited, which can not only smoothly divide the flow, but also further reduce the wind noise at the volute tongue 100 .

In some embodiments, please continue to refer to FIG. 5 and FIG. 6 , the connection line between the pole O of the logarithmic spiral curve and the arc center O2 of the second type line segment L2 is the first connection line L5, and the connection between the pole O and the first intersection C1 The connecting line is the second connecting line L6, and the included angle between the first connecting line L5 and the second connecting line L6 is α1. Among them, 76°≤α1≤86°. That is to say, the construction starting point of the third type line segment L3 is located on the reference circle P, and the line segment between the construction starting point of the third type line segment L3 and the starting point of the third type line segment L3, after obtaining the starting point of the third type line segment L3 , can be removed, which further defines the shape of the third-shaped line segment L3 to match the impeller 20 and improve the smoke exhaust efficiency of the volute. In this way, by defining the included angle between the first connecting line L5 and the second connecting line L6, not only the arc length of the second-shaped line segment L2 can be limited, the volute tongue 100 of the preset shape can be constructed, and the wind noise can be reduced. The starting point of the third-shaped line segment L3 to further improve the dynamic characteristics of the fluid flowing through the volute tongue 100 .

In some embodiments, please continue to refer to FIG. 5 , the fourth-type line segment L4 is a straight line, and the included angle between the fourth-type line segment L4 and the second connecting line L6 is α2 . Among them, 80°≤α2≤90°. Taking FIG. 5 as an example, the case where the included angle α2 is 90° is illustrated. In this way, a reasonable expansion angle of the volute can be obtained, the gas inside the volute is prevented from flowing back into the volute, and the exhaust efficiency is improved.

In some embodiments, please continue to refer to FIG. 5 , the length of the line connecting the first intersection point C1 and the second tangent point T2 is d2 . Among them, the ratio of r to d2 is 1.38-1.56. That is to say, the first intersection point C1 is the construction start point of the third type line segment L3, and the second tangent point T2 is the construction end point of the third type line segment L3. By defining the construction start point of the third type line segment L3 and the third type line segment L3 The distance between the construction end points can limit the third-shaped line segment L3, and further limit the curvature of the third-shaped line segment L3, which further reduces the error of the volute molding line. In addition, the flow rate of the air flow to the air outlet 200 is limited, which does not affect the exhaust efficiency and reduces noise.

In some embodiments, the equation of the logarithmic spiral curve is:

为对数螺旋曲线的极半径与第二连线L6的夹角，

为R的修正值。如此，通过设置修正值，对螺旋曲线进行修正，可以降低蜗壳型线的误差。Wherein, r is the radius of the impeller 20, e is the base of the natural logarithm, a is the back flow angle of the blades of the impeller 20, b is the outlet width of the impeller 20 (that is, the height of the impeller 20 shown in FIG. 4 in the up-down direction) ), B is the height of the volute (that is, the height of the volute shown in FIG. 4 in the up-down direction, that is, the distance between the upper plate 300 of the volute and the bottom plate 400 of the volute),

is the angle between the pole radius of the logarithmic spiral curve and the second connecting line L6,

is the corrected value of R. In this way, by setting the correction value to correct the helical curve, the error of the volute profile can be reduced.

In some embodiments, the maximum rotational speed of the impeller 20 is 800r/min-1000r/min, and l is 10mm-15mm. In other embodiments, the maximum rotational speed of the impeller 20 is 600r/min-800r/min, and l is 5mm-10mm. In this way, different degrees of correction can be performed according to the impellers 20 with different rotational speeds.

Based on the same inventive concept, the embodiment of the present application provides a centrifugal fan, which includes an impeller 20 and the volute in the above embodiment. Wherein, the impeller 20 is arranged in the volute, and the center of the impeller 20 coincides with the pole O of the logarithmic spiral curve. In this way, the centrifugal fan can have high smoke exhaust efficiency and low noise.

In some embodiments, the number of blades of the impeller 20 is 64-70 blades. In this way, the profile of the volute and the impeller 20 can be more matched, the smoke exhaust efficiency of the volute can be improved, and the noise can be reduced.

Based on the same inventive concept, an embodiment of the present application provides a range hood, including the centrifugal fan in the above embodiment. In this way, the smoke exhausting efficiency of the range hood can be high and the noise is low.

FIG. 7 shows a schematic diagram of the structure of the volute profile in an embodiment of the present application; for the convenience of description, only the parts related to the embodiment of the present application are shown.

The following will illustrate the construction method of the volute profile of the volute provided by the embodiment of the present application. Please refer to FIG. 7 , and the steps are as follows:

形成螺旋曲线S；S100. Construct a logarithmic spiral curve: take any point as the pole of the logarithmic spiral curve, determine the radius r of the impeller 20, and take the radius r of the impeller 20 as the initial radius, and take the endpoint A on the initial radius as the logarithmic spiral curve The starting point of , according to the equation of the logarithmic spiral curve

form a spiral curve S;

角度76°-86°的位置确定第二型线段L2，且第二型线段L2与参考圆P之间最小距离为15mm-23mm，第二型线段L2的圆弧半径为13mm-18mm；S200, constructing the second type line segment L2: at the included angle

The position of the angle 76°-86° determines the second type line segment L2, and the minimum distance between the second type line segment L2 and the reference circle P is 15mm-23mm, and the arc radius of the second type line segment L2 is 13mm-18mm;

S300, constructing a third-shaped line segment L3: take the end point of the second-shaped line segment L2 as the starting point of the third-shaped line segment L3, and use the point B on the spiral curve S with a distance of 85 mm-95 mm from the end point A as the third-shaped line segment L3 The end point, and the third-type line segment L3 is tangent to the second-type line segment L2;

S400, constructing a fourth-type line segment L4: the included angle between the fourth-type line segment L4 and the line segment OA is 80°-90°, and the fourth-type line segment L4 is tangent to the third-type line segment L3;

S500 , constructing a first-type line segment L1 : the first-type line segment L1 and the second-type line segment L2 are tangent to the starting point of the second-type line segment L2 .

Fig. 8 shows a schematic diagram of a sound pressure nephogram of a volute provided in an embodiment of the present application; Fig. 9 shows a schematic diagram of a sound pressure nephogram of a volute provided in another embodiment of the present application; Fig. 10 shows the present application Another embodiment provides a schematic diagram of a sound pressure nephogram of a volute; for the convenience of description, only the parts related to the embodiments of the present application are shown.

为80°的蜗舌100处的声压强度分别为59db，图9中所示意处的蜗壳中，蜗壳与叶轮20外缘之间最小距离为19mm，在夹角

为80°的蜗舌100处的声压强度分别为53db，图10中所示意处的蜗壳中，蜗壳与叶轮20外缘之间最小距离为23mm，在夹角

为80°的蜗舌100处的声压强度分别为49db。由此可见，蜗壳的蜗舌100处气动噪声有明显改善。In the above embodiment, d2=90mm, α2=90°, the arc radius R of the volute tongue 100 is 15mm, l=10mm, the number of blades of the impeller 20 is 64, the radius r of the impeller 20 is 132mm, and Ansys is used below. The fluent simulation software of the present application performs aerodynamic simulation on the volute provided by the embodiment of the application, and the minimum distance between the volute and the outer edge of the impeller 20 (that is, the length of the connecting line between the second intersection C2 and the first tangent point T1) is 15mm. , 19mm, 23mm as examples to simulate. It should be noted that, in FIGS. 8 to 10 , U1 represents the color corresponding to the sound pressure intensity in different regions, and U2 represents the specific sound pressure intensity, and the unit is dB. Different sound pressure intensities have different colors, and as the sound pressure intensity changes, the color will also change. The color change refers to the gradual transition of the color from a cool tone to a warm tone as the sound pressure intensity increases. As shown in FIGS. 8 to 10 , the color changes appear as a gradual transition from cool to warm colors in a clockwise direction from the volute tongue 100 , and in FIGS. 8 to 10 , most of the colors are cool colors. In the volute shown in Fig. 8, the minimum distance between the volute and the outer edge of the impeller 20 is 15mm, at the included angle

The sound pressure intensity at the volute tongue 100 with an angle of 80° is 59db, respectively. In the volute shown in Fig. 9, the minimum distance between the volute and the outer edge of the impeller 20 is 19mm.

The sound pressure intensity at the volute tongue 100 with an angle of 80° is 53db respectively. In the volute case shown in Figure 10, the minimum distance between the volute case and the outer edge of the impeller 20 is 23mm.

The sound pressure intensity at the volute tongue 100 at 80° is 49db, respectively. It can be seen that the aerodynamic noise at the volute tongue 100 of the volute is significantly improved.

To sum up, in the volute profile of the volute provided by the embodiment of the present application, since the logarithmic spiral curve where the third profile line segment L3 is located is an arc segment generated by the same circle center, the curvature of the third profile segment is continuous. At the same time, by designing the reference circle P, the radial gap t between the logarithmic spiral curve and the reference circle P is gradually increased, so that the change of the polar radius of the third type line segment L3 is continuous, reducing the volute case. The error of the profile line can not only prevent eddy currents in the volute to reduce the noise of the volute, but also make the gas in the volute more concentrated and improve the smoke exhaust efficiency of the volute. By limiting the shape of the volute tongue 100 and the distance between the volute tongue 100 and the impeller 20, the wind noise generated by the fluid shunt at the volute tongue 100 is prevented from being transmitted to the outside through the volute tongue 100, which affects the user's experience. By defining the angle of the fourth-shaped line segment L4, more gas inside the volute is prevented from flowing back into the volute, thereby improving the exhaust efficiency.

The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, all It is considered to be the range described in this specification.

The above-mentioned embodiments only represent several embodiments of the present application, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the appended claims.

Claims (11)

1. A volute is characterized in that the molded line of the volute comprises a first molded line segment (L1), a second molded line segment (L2), a third molded line segment (L3) and a fourth molded line segment (L4) which are connected in sequence, and the two connected molded line segments are in smooth transition; the third type line segment (L3) forms the main body of the volute, the second type line segment (L2) forms the volute tongue (100) of the volute, the first type line segment (L1) and the fourth type line segment (L4) form the air outlet (200) of the volute, and the third type line segment (L3) is located on a logarithmic spiral curve;

the third type line segment (L3) and the second type line segment (L2) are tangent to a first tangent point (T1), the third type line segment (L3) and the fourth type line segment (L4) are tangent to a second tangent point (T2), and a direction from the first tangent point (T1) to the second tangent point (T2) along the third type line segment (L3) is a first path direction; defining a circle with the pole (O) of the logarithmic spiral as the center and the radius r of an impeller (20) in the volute as the radius as a reference circle (P), wherein the logarithmic spiral intersects the reference circle (P) at a first intersection point (C1), and a radial gap (T) is constructed between the outline of the reference circle (P) and the logarithmic spiral between the first intersection point (C1) and the second tangent point (T2);

wherein, in the first path direction, the radial gap (t) gradually increases and the curvature of the third type line segment (L3) is continuous.

2. A spiral casing according to claim 1, characterized in that a line connecting the pole (O) and the first tangent point (T1) intersects the profile of the reference circle (P) at a second intersection point (C2), the length of the line connecting the second intersection point (C2) and the first tangent point (T1) being d 1;

wherein the ratio of r to d1 is 5.73-8.8.

3. The spiral casing as claimed in claim 1, wherein the second profile segment (L2) is a circular arc, the circular arc radius of the second profile segment (L2) being R;

wherein the ratio of R to R is 7.33-10.15.

4. A spiral casing according to any of claims 1-3, characterized in that the line connecting the pole (O) of the logarithmic spiral with the arc center (O2) of the second type segment (L2) is a first line (L5), the line connecting the pole (O) and the first intersection point (C1) makes an angle α 1 with the first line (L5);

wherein alpha 1 is more than or equal to 76 degrees and less than or equal to 86 degrees.

5. The spiral casing according to any of the claims 1-3, characterized in that the fourth type line segment (L4) is a straight line and the fourth type line segment (L4) has an angle α 2 with the line connecting the pole (O) and the second intersection point (C2);

wherein alpha 2 is more than or equal to 80 degrees and less than or equal to 90 degrees.

6. The spiral casing of any of claims 1-3 wherein the first intersection point (C1) is connected to the second tangent point (T2) with a length d 2;

wherein the ratio of r to d2 is 1.38-1.56.

7. The spiral casing of any of claims 1 to 3 wherein the equation for the logarithmic spiral is:

wherein r is the radius of the impeller (20), e is the base of the natural logarithm, a is the back flow angle of the blades of the impeller (20), B is the outlet width of the impeller (20), and B is the height of the volute,

is the angle between the polar radius of the logarithmic spiral and the line connecting the pole (O) and the first intersection point (C1),

is a correction value for R.

8. The spiral casing according to claim 7, wherein the impeller (20) has a maximum rotational speed of 800r/min-1000r/min, l being 10mm-15 mm;

the maximum rotating speed of the impeller (20) is 600r/min-800r/min, and l is 5mm-10 mm.

9. A centrifugal fan comprising an impeller (20) and a volute according to any of claims 1-8;

wherein the impeller (20) is arranged in the volute, and the center of the impeller (20) is superposed with the pole (O) of the logarithmic spiral curve.

10. The centrifugal fan according to claim 9, wherein the impeller (20) has a number of blades of 64-70 blades.

11. A range hood comprising a centrifugal fan according to claim 9 or 10.

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