Centrifugal fans and household appliances

Abstract

This invention discloses a centrifugal fan and a household appliance incorporating it, relating to the field of fan technology. The volute includes a helical surface and a volute tongue. An impeller is housed within the volute. The helical surface includes a first guide section, with point P connecting the helical surface and the volute tongue. The endpoint of the first guide section near the volute tongue is the starting point A, and the endpoint away from the volute tongue is the ending point B. The distance from the impeller's rotation center O to the starting point A is OA, and the distance from the impeller's rotation center O to any point C in the first guide section is OC, satisfying OA ≥ OC. The first guide section includes an arc portion, and the distance from the impeller's rotation center O to any point in the arc portion is equidistant. By setting the first guide section and reducing the distance between it and the impeller, the flow rate is increased, power is reduced, and noise is decreased at the same rotational speed. The equidistant distance from the arc portion to the impeller's rotation center O further reduces power consumption and noise.

Description

Technical Field

[0001] This invention relates to the field of fan technology, and particularly to centrifugal fans and household appliances. Background Technology

[0002] Due to space constraints in home appliances, the overall size of centrifugal fans is often severely limited. These size limitations, in turn, lead to problems such as high noise and low efficiency, failing to meet the future demands of the home appliance industry for quiet and efficient operation. Therefore, with the trend towards miniaturization in home appliances, achieving greater airflow, lower noise, and lower power consumption within increasingly smaller spaces presents a significant challenge to centrifugal fan design. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a centrifugal fan that can improve the fan's work capacity and reduce the fan's power consumption and noise at the same air volume.

[0004] The present invention also proposes a household appliance having the above-mentioned centrifugal fan.

[0005] According to a first aspect of the present invention, a centrifugal fan includes a volute and an impeller. The volute includes a helical surface and has a volute tongue. The impeller is disposed within the volute. The helical surface includes a first guide section. The connection point between the helical surface and the volute tongue is defined as point P. The endpoint of the first guide section near the volute tongue is defined as starting point A, and the endpoint of the first guide section away from the volute tongue is defined as ending point B. The distance from the rotation center O of the impeller to the starting point A is OA, and the distance from the rotation center O of the impeller to any point C of the first guide section is OC, satisfying OA ≥ OC. The first guide section includes an arc portion, and the distance from the rotation center O of the impeller to any point of the arc portion is equal.

[0006] The centrifugal fan according to embodiments of the present invention has at least the following beneficial effects: by setting a first guide section and reducing the distance between the first guide section and the impeller, the diameter of the impeller can be increased within the same space, thereby achieving the effects of increasing flow rate, reducing power, and reducing noise at the same rotational speed. Furthermore, the distance from the arc portion to the rotation center O of the impeller is equal, which further reduces power and noise.

[0007] According to some embodiments of the present invention, the helical surface includes a second guide section and a third guide section. The second guide section is located on the side of the first guide section away from the point P, and the third guide section is located on the side of the second guide section away from the first guide section. The endpoint of the third guide section on the side away from the second guide section is the endpoint I of the helical surface. Along the direction away from the point P, the distance from the rotation center O of the wind turbine to the second guide section gradually decreases or remains constant, while the distance from the rotation center O of the wind turbine to the third guide section gradually increases.

[0008] According to some embodiments of the present invention, the helical surface includes a second guide section and a third guide section. The second guide section is located on the side of the first guide section away from the point P, and the third guide section is located on the side of the second guide section away from the first guide section. The endpoint of the third guide section on the side away from the second guide section is the endpoint I of the helical surface. Along the direction away from the point P, the distance from the rotation center O of the wind turbine to the second guide section gradually increases, and the distance from the rotation center O of the wind turbine to the third guide section gradually increases or remains unchanged.

[0009] According to some embodiments of the present invention, the helical surface has points D and E, with an included angle ∠POD = 90°, and point E is located between points P and D, satisfying: OE ≤ OP, and / or, OD ≤ OE.

[0010] According to some embodiments of the present invention, the helical surface has points D, G, and H, with included angles ∠POD = 90° and ∠DOG = 90°. Point G is located on the side of point D away from point P. Along the direction from point D to point G, the distance from the rotation center O of the wind turbine to the helical surface between points D and G gradually increases. Alternatively, point H is located between points D and G, satisfying: OH ≤ OD, and / or, OG ≤ OH.

[0011] According to some embodiments of the present invention, the first guide section includes a gradient section, and along the direction away from the point P, the distance from the rotation center O of the wind turbine to the gradient section gradually decreases, and the arc length of the gradient section is smaller than the arc length of the circular arc section.

[0012] According to some embodiments of the present invention, the gradient portion is located on the side of the arc portion closer to the point P.

[0013] According to some embodiments of the present invention, the first guide section is entirely composed of the arc portion.

[0014] According to some embodiments of the present invention, the helical surface includes a first expanding segment, the two ends of the first expanding segment being the point P and the starting point A, respectively, and the distance from the rotation center O of the wind turbine to the first expanding segment gradually increases along the direction away from the point P.

[0015] According to some embodiments of the present invention, the helical surface includes a second expanding section, which is located on the side of the first guide section away from the point P. Along the direction away from the point P, the distance from the rotation center O of the wind turbine to the second expanding section gradually increases.

[0016] According to some embodiments of the present invention, the extension path of the helical surface along the circumference is a smooth and continuous curve.

[0017] A household appliance according to a second aspect of the present invention includes a centrifugal fan according to a first aspect of the present invention.

[0018] The household appliances according to embodiments of the present invention have at least the following beneficial effects: by employing the centrifugal fan of the first aspect embodiment of the present invention, it is helpful to realize the miniaturization of household appliances.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of a centrifugal fan according to an embodiment of the present invention; Figure 2 for Figure 1 A cross-sectional view of one embodiment of the centrifugal fan is shown; Figure 3 for Figure 1 A cross-sectional view of another embodiment of the centrifugal fan is shown; Figure 4 for Figure 1 A cross-sectional view of another embodiment of the centrifugal fan is shown; Figure 5 for Figure 1 A cross-sectional view of another embodiment of the centrifugal fan is shown; Figure 6 for Figure 1 A cross-sectional view of another embodiment of the centrifugal fan is shown; Figure 7 This is a comparison chart of noise test data between a centrifugal fan of the present invention (which has a first guide section that is entirely arc-shaped and partly gradually transitioned and partly arc-shaped) and a centrifugal fan of related technologies. Figure 8 This is a comparison chart of power test data between a centrifugal fan of the present invention (which has a first guide section that is entirely arc-shaped and partly gradually transitioned and another part is arc-shaped) and a centrifugal fan of related technologies.

[0021] Figure label: 101. Volute; 101'. Casing; 102. Side panel; 103. Enclosure panel; 104. Air outlet; 105. Air inlet; 106. Fan wheel; 106'. Impeller; 201. Spiral tongue; 202. Helical surface; 203. Second gradually expanding section; 204. First guide section; 301. First gradual expansion phase. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0023] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0024] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0025] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0026] Centrifugal fans have the advantages of long air delivery distance and strong pressure resistance. They are widely used in various industries, especially in the home appliance industry, where air conditioners, water heaters, range hoods, refrigerators, etc. use centrifugal fans. Their structure usually consists of a volute, impeller, motor, and outlet diffuser.

[0027] Reference Figure 1 As shown, the volute 101 provided in this embodiment of the invention includes two side plates 102 and a surrounding plate 103 arranged at relatively intervals. The surrounding plate 103 is connected between the two side plates 102. The two side plates 102 and the surrounding plate 103 together define a blower cavity and an air outlet 104 communicating with the blower cavity. An air inlet 105 communicating with the blower cavity is provided on the side plate 102. In this application, the air inlet 105 may be provided on one side plate 102 or on both side plates 102. There is no limitation on this. Both the side plates 102 and the surrounding plate 103 may be made of sheet metal. The surrounding plate 103 is a long strip of plate, and the outer main body outline of the entire volute 101 is formed by bending the plate. The two side plates 102 respectively cover the front and rear sides of the surrounding plate 103.

[0028] Reference Figure 1 As shown, the centrifugal fan provided in this embodiment of the invention includes a impeller 106 and the aforementioned volute 101. The impeller 106 is disposed inside the blower chamber and can rotate within the blower chamber. During the operation of the centrifugal fan, the airflow entering through the air inlet 105 on the side plate 102 will undergo multiple reversals and will finally be discharged from the air outlet 104 in an upward direction.

[0029] Reference Figure 2 As shown, it can be understood that the volute 101 is provided with a volute tongue 201, and a helical surface 202 is formed on the enclosure 103. The volute tongue 201 is arc-shaped and is connected to the end of the helical surface 202 near the air outlet 104. The helical surface 202 is set along the extension direction of the profile of the volute 101. The rotation center of the impeller 106 is defined as point O, the connection point between the helical surface 202 and the volute tongue 201 is defined as point P, and the end point of the helical surface 202 away from the volute tongue 201 is defined as point I. There are also points D and G between points P and I, satisfying the included angle ∠POD=90° and the included angle ∠DOG=90°.

[0030] It needs to be explained that, Figures 1 to 6 This is a cross-sectional view of a centrifugal fan. The cross-sections of the volute 101 and the impeller 106 are lines, as shown. Figure 2 As shown, the distance between the helical surface 202 and the rotation center of the wind turbine 106 refers to the minimum distance between the inner surface of the helical surface 202 and the rotation axis centerline of the wind turbine 106.

[0031] In related technologies, the traditional design method for centrifugal fan casing 101' simplifies the airflow inside casing 101' to a flow with conserved angular momentum and no flow loss, thus obtaining a logarithmic spiral as the casing profile of centrifugal fan 101'. To limit the radial dimension of the fan, the Archimedes spiral method, equilateral element method, or scalene element method are usually used to draw the casing profile of 101'. This ensures that the distance from the rotation center of impeller 106' to the wall of casing 101' is minimized at the volute tongue 201, and then gradually increases according to a certain pattern.

[0032] in, Figures 2 to 5 The impeller 106' coincides with the wind turbine 106. To make the view simpler and clearer, the relevant features of the impeller 106' in the corresponding view are replaced with the corresponding features of the wind turbine 106. (Refer to...) Figure 2 As shown in the figure, the dashed line represents the casing 101' obtained by the traditional design method. The distance OD' from the rotation center O of the impeller 106 to the profile line D' of the casing 101' is greater than the distance OP from the center O of the impeller 106 to the starting point P of the profile line of the casing 101', i.e., OD' > OP; the distance OG' from the rotation center O of the impeller 106 to the profile line G' of the casing 101' is greater than the distance OD' from the rotation center O of the impeller 106 to the profile line D' of the casing 101', i.e., OG' > OD'; the distance OI from the rotation center O of the impeller 106 to the profile line I of the casing 101' is greater than the distance from the rotation center O of the impeller 106 to the profile line G' of the casing 101', i.e., OI > OG'. Wherein, ∠POD' = 90°, and the included angle ∠D'OG' = 90°.

[0033] Due to space constraints imposed by home appliances, the overall size of centrifugal fans is often severely limited. These size limitations, in turn, lead to problems such as high noise and low efficiency, failing to meet the future demands of the home appliance industry for quiet and efficient operation. Therefore, with the trend towards miniaturization in home appliances, achieving greater airflow, lower noise, and lower power consumption within increasingly smaller spaces presents a significant challenge to centrifugal fan design.

[0034] Reference Figure 2As shown, it can be understood that the centrifugal fan provided in this embodiment of the invention includes a first guide section 204 in its helical surface 202. The first guide section 204 has a starting point A and an ending point B. In the extension direction from point P to point I of the helical surface 202, the starting point A is the endpoint of the first guide section 204 near the volute tongue 201, and the ending point B is the endpoint of the first guide section 204 away from the volute tongue 201. In the extension path from the starting point A to the ending point B, there exists any point C such that the distance from the rotation center O of the impeller 106 to the starting point A is OA, and the distance from the rotation center O of the impeller 106 to any point C of the first guide section 204 is OC, satisfying: OA≥OC. Point C can be between the starting point A and the ending point B, or it can coincide with the ending point B. That is, in the first guide section 204, starting from the starting point A, the distance from the rotation center of the impeller 106 to the helical surface 202 is the largest at the starting point A, and then gradually decreases or remains unchanged according to a certain rule.

[0035] Reference Figure 2 As shown, when the first guide section 204 is located between point P and point D, the first guide section 204 changes the extension direction of the profile of the spiral surface 202, making the profile of the spiral surface 202 closer to the rotation center O of the impeller 106. Consequently, point D, which is close to the first guide section 204, becomes closer to the rotation center O of the impeller 106 as the profile of the spiral surface 202 changes, i.e., OD < OD'. The volute 101 provided in this embodiment of the invention reduces its height in the vertical direction.

[0036] It is understandable that when point D is located on the first guide section 204, the vertical height of the volute 101 is also reduced.

[0037] Reference Figure 2 As shown, it can be understood that the starting point A can coincide with point P, that is, from the connection point P between the spiral surface 202 and the volute tongue 201 to the end point B of the first guide section 204, the distance from the rotation center O of the impeller 106 to the spiral surface 202 is either decreasing or unchanged.

[0038] Reference Figure 3 As shown, when the first guide section 204 is located between point D and point G, the first guide section 204 changes the extension direction of the profile of the spiral surface 202, making the profile of the spiral surface 202 closer to the rotation center O of the impeller 106. Consequently, point G, which is close to the first guide section 204, becomes closer to the rotation center O of the impeller 106 as the profile of the spiral surface 202 changes, i.e., OG < OG'. The volute 101 provided in this embodiment of the invention has reduced its width in the horizontal direction.

[0039] Understandably, point G is located on the first guide section 204, which also reduces the width of the volute 101 in the horizontal direction.

[0040] Reference Figure 3 As shown, it can be understood that the starting point A can be set at an interval with point P, that is, there is a first expanding segment 301 between the starting point A and point P. The two ends of the first expanding segment 301 are point P and the starting point A, respectively. Along the direction away from point P, the distance from the rotation center O of the wind turbine 106 to the first expanding segment 301 gradually increases. The first expanding segment 301 can be made using the Archimedean spiral method, the equilateral primitive method, or the scalene primitive method.

[0041] In summary, the centrifugal fan provided by this embodiment of the invention achieves the goal of reducing the size of the volute 101 in the region where the first guide section 204 is located. The parameters affecting the overall size of the product are mainly the height in the vertical direction and the width in the horizontal direction. In particular, since the outer peripheral surface of the volute 101 is curved, changes in dimensional parameters in other directions have a relatively small impact on the overall size. Therefore, compared with the size of traditional design schemes, the centrifugal fan provided by this embodiment of the invention can effectively reduce the size.

[0042] It is understandable that the first guide section 204 includes a transition section and an arc section. Along the direction away from point P, the distance from the rotation center O of the wind turbine 106 to the transition section gradually decreases, and the distance from the rotation center O of the wind turbine 106 to any point on the arc section is equal. That is, there are two consecutive points on the arc section that are equidistant from the rotation center O of the wind turbine 106.

[0043] Understandably, in some embodiments, the gradient portion is located on the side of the arc portion closer to point P. The spiral surface 202's profile extension path in the first guide section 204 first decreases in distance from the rotation center O of the impeller 106, then remains constant. Subsequent profile extension paths all follow this initial decrease before further extension, thus reducing the overall size of the spiral surface 202.

[0044] It should be noted that in some other embodiments, the gradient portion may also be located on the side of the arc portion away from point P, or the gradient portion may be provided on both sides of the arc portion, or the arc portion may be provided on both sides of the gradient portion. The relative position and specific number of the arc portion and the gradient portion are not limited.

[0045] Reference Figure 7 As shown, it can be understood that the data in the dashed lines of the figure represents the noise data collected by the centrifugal fan using the traditional design method, while the data in the dotted and solid lines represent the noise data collected by the centrifugal fan improved using the embodiments of this invention. The horizontal axis in the figure represents air volume, and the vertical axis represents noise. From Figure 7As can be seen, with the increase of air volume, the noise generated by the centrifugal fan obtained by the traditional design method and the noise generated by the centrifugal fan improved by the embodiment of the present invention both increase continuously. However, under the same air volume, the noise generated by the centrifugal fan obtained by the traditional design method is greater than the noise generated by the centrifugal fan improved by the embodiment of the present invention.

[0046] Reference Figure 8 As shown, it can be understood that the data in the dashed lines of the figure represents the power data collected by the centrifugal fan using the traditional design method, while the data in the dotted and solid lines represent the power data collected by the centrifugal fan improved using the embodiments of this invention. The horizontal axis in the figure represents air volume, and the vertical axis represents power. From Figure 8 As can be seen, with the increase of air volume, the power required by the centrifugal fan obtained by the traditional design method and the power required by the centrifugal fan improved in the embodiments of the present invention both increase continuously. However, under the same air volume, the power generated by the centrifugal fan obtained by the traditional design method is greater than the power generated by the centrifugal fan improved in the embodiments of the present invention. In other words, under the same power, the air volume generated by the centrifugal fan obtained by the traditional design method is less than the air volume generated by the centrifugal fan improved in the embodiments of the present invention.

[0047] according to Figure 7 and Figure 8 It can be seen that, regardless of whether the first guide section 204 is partly a gradual transition section and partly a circular arc section, or entirely composed of circular arc sections, the improved centrifugal fan can reduce power and noise compared to centrifugal fans designed using traditional methods.

[0048] Reference Figure 7 As shown, it can be understood that the data along the long dashed line in the figure represents the noise data collected by the centrifugal fan in the first guide section 204, which has a gradual transition section and another section that is an arc. The data along the solid line represents the noise data collected by the centrifugal fan in the first guide section 204, which is entirely an arc. The horizontal axis in the figure represents airflow, and the vertical axis represents noise. From Figure 7 As can be seen, the noise generated by both centrifugal fans increases with the increase of air volume. However, under the same air volume, the noise generated by the centrifugal fan with a gradual transition section and a circular arc section in the first guide section 204 is greater than the noise generated by the centrifugal fan with the entire first guide section 204 being a circular arc section.

[0049] Reference Figure 8 As shown, it can be understood that the data along the long dashed line in the figure represents the power data collected by the centrifugal fan in the first guide section 204, which has a gradual transition section and another section that is an arc. The data along the solid line represents the power data collected by the centrifugal fan in the first guide section 204, which is entirely an arc. The horizontal axis in the figure represents air volume, and the vertical axis represents power. From Figure 8As can be seen, the power required by both types of centrifugal fans increases with the increase in air volume. However, at the same air volume, the centrifugal fan with a partially transitional section and a partially circular section in the first guide section 204 generates more power than the centrifugal fan with the entire first guide section 204 being a circular section. In other words, at the same power, the air volume generated by the centrifugal fan with the entire first guide section 204 being a transitional section is less than the air volume generated by the centrifugal fan with the entire first guide section 204 being a circular section.

[0050] according to Figure 7 and Figure 8 It can be seen that in the improved centrifugal fan, the first guide section 204 adopts a design entirely with arc sections. Compared to a design where the first guide section 204 is partly a gradient section and partly an arc section, this design can further reduce power consumption and noise. In other words, both gradient sections and arc sections can effectively reduce the size of the centrifugal fan, but a higher proportion of arc sections results in better power reduction and noise reduction.

[0051] Understandably, in some embodiments, the arc length of the gradient section is less than the arc length of the circular arc section, and the angle formed by the lines connecting the two ends of the gradient section and the rotation center O of the impeller 106 is less than the angle formed by the lines connecting the two ends of the circular arc section and the rotation center O of the impeller 106. By reducing the proportion of the gradient section and increasing the proportion of the circular arc section, power consumption and noise can be effectively reduced. The proportion of the gradient section in the first guide section 204 can be reduced to zero, that is, the entire first guide section 204 is a circular arc section. The first guide section 204 being a circular arc section can achieve a better effect in reducing power consumption and noise.

[0052] When the diameter of the impeller 106 remains unchanged, the centrifugal fan provided in this embodiment of the invention is smaller in size than the centrifugal fan of the traditional solution, while its air volume (mainly affected by the diameter of the impeller 106 and the motor power), noise and power remain at a comparable level, contributing to the reduction of the size of home appliances.

[0053] It is understood that in some embodiments, the helical surface 202 includes a second guide section and a third guide section. The second guide section is located on the side of the first guide section 204 away from point P, and the third guide section is located on the side of the second guide section away from the first guide section 204. The endpoint of the third guide section on the side away from the second guide section is the endpoint I of the helical surface 202. Along the direction away from point P, the distance from the rotation center O of the wind turbine 106 to the second guide section gradually decreases, and the distance from the rotation center O of the wind turbine 106 to the third guide section gradually increases.

[0054] For example, starting point A coincides with point P, and ending point B coincides with point D, meaning that the spiral surface 202 is in the first guide section 204 from point P to point D. The spiral surface 202 is in the second guide section from point D to point G, and in the third guide section from point G to point I. The distance from the region of the spiral surface 202 in the first guide section 204 and the second guide section to the rotation center O of the impeller 106 is smaller than the size obtained by the traditional design method. The distance from the rotation center O of the impeller 106 to the third guide section gradually increases in order to keep the distance OI from the rotation center O of the impeller 106 to the endpoint I of the spiral surface 202 basically equal to the size obtained by the traditional design method, thereby ensuring the air intake of the last section of the volute 101 and controlling the air outlet speed of the centrifugal fan.

[0055] It is understood that in some embodiments, the helical surface 202 includes a second guide section and a third guide section. The second guide section is located on the side of the first guide section 204 away from point P, and the third guide section is located on the side of the second guide section away from the first guide section 204. The endpoint of the third guide section on the side away from the second guide section is the endpoint I of the helical surface 202. Along the direction away from point P, the distance from the rotation center O of the wind turbine 106 to the second guide section gradually increases, and the distance from the rotation center O of the wind turbine 106 to the third guide section gradually increases or remains unchanged.

[0056] For example, starting point A coincides with point P, and ending point B coincides with point D, meaning that the spiral surface 202 is in the first guide section 204 from point P to point D. The spiral surface 202 is in the second guide section from point D to point G, and in the third guide section from point G to point I. The distance from the region of the spiral surface 202 in the first guide section 204 to the rotation center O of the impeller 106 is smaller than the size obtained using the traditional design method. The distance from the rotation center O of the impeller 106 to the second guide section gradually increases, and the distance from the rotation center O of the impeller 106 to the third guide section gradually increases or remains unchanged. This is to ensure that the distance OI from the rotation center O of the impeller 106 to the endpoint I of the spiral surface 202 remains basically equal to the size obtained using the traditional design method, thereby ensuring the air intake volume of the last section of the volute 101 and controlling the air outlet speed of the centrifugal fan.

[0057] It should be noted that the specific locations of the first guide segment 204, the second guide segment, and the third guide segment are not limited to the examples above. For example, the location of the first guide segment 204 can be between point P and point D, or between point P and point G. Correspondingly, the location of the second guide segment can be between point P and point G, or between point G and point I.

[0058] Reference Figure 2As shown, it is understandable that in order to ensure the air intake volume of the last section of the volute 101 and control the air outlet speed of the centrifugal fan, the helical surface 202 needs to be provided with a second gradually expanding section 203 on the side of the first guide section 204 away from point P. Along the direction away from point P, the distance from the rotation center O of the impeller 106 to the second gradually expanding section 203 gradually increases, so that the distance OI from the rotation center O of the impeller 106 to the endpoint I of the helical surface 202 can be kept basically equal to the size obtained by using the traditional design method. The second gradually expanding section 203 can be made using the Archimedean spiral method, the equilateral element method, or the scalene element method.

[0059] Reference Figure 4 As shown, it can be understood that the helical surface 202 has a point E, located between points P and D, satisfying at least one of the following conditions: OE ≤ OP, or OD ≤ OE. When OE = OP, the section from point P to point E is the first guide segment 204. When OD = OE, the section from point E to point D is the first guide segment 204. When OE = OP = OD, or OE = OP and OD < OE, or OE < OP and OE = OD, the section from point P to point D is the first guide segment 204. When OE < OP and OD < OE, the first guide segment 204 is located between points D and G, which can effectively reduce the vertical height and horizontal width of the centrifugal fan.

[0060] Reference Figure 5 As shown, it can be understood that the helical surface 202 has a point H, located between points D and G, satisfying at least one of the following conditions: OH ≤ OD, or OG ≤ OH. When OH = OD, the section from point D to point H is the first guide segment 204. When OG = OH, the section from point H to point G is the first guide segment 204. When OH = OD = OG, or OH = OD and OG < OH, or OH < OD and OG = OH, the section from point D to point G is the first guide segment 204. When OH < OD and OG < OH, the first guide segment 204 is located between points P and D, which can effectively reduce the vertical height and horizontal width of the centrifugal fan.

[0061] Reference Figure 6As shown, it can be understood that the solid lines in the figure represent the volute 101 and impeller 106 provided in the embodiment of the present invention, while the dashed lines represent the casing 101' and impeller 106' of the conventional design. When the installation space for the centrifugal fan is limited, and the overall size of the centrifugal fan remains unchanged (i.e., the vertical height and horizontal width of the volute 101 remain unchanged), the diameter of the impeller 106 in the embodiment of the present invention is larger than that of the impeller 106' obtained by the conventional design method because the rotation center distance between the volute 101 and the impeller 106 in the embodiment of the present invention is smaller. Therefore, the fan speed, power, and noise of the embodiment of the present invention are lower than those of the conventional design method when the required air volume is the same.

[0062] It is understood that the circumferential extension path of the helical surface 202 is a smooth and continuous curve. That is, the profile of the helical surface 202 in this embodiment of the invention is always continuous and smooth. Along the circumference of the helical surface 202, the helical surface 202 extends from point P, through points D and G to I, and is always a smooth and continuous curve without straight line segments or discontinuous first derivatives of the curve. Therefore, it is not necessary to design the volute 101 with trimming to prevent performance loss caused by discontinuous flow.

[0063] The household appliances provided in this invention include air conditioners, water heaters, range hoods, refrigerators, and other products. These appliances utilize the centrifugal fan provided in this invention, which helps to achieve miniaturization of household appliances. Within the same space, the diameter of the impeller 106 can be increased, thereby increasing airflow, reducing power consumption, and decreasing noise at the same rotational speed.

[0064] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A centrifugal fan, characterized in that, include: A volute, including a helical surface, wherein the volute is provided with a volute tongue; The impeller is located inside the volute. The spiral surface includes a first guide section. The connection point between the spiral surface and the volute tongue is defined as point P. The endpoint of the first guide section near the volute tongue is defined as starting point A, and the endpoint of the first guide section away from the volute tongue is defined as ending point B. The distance from the rotation center O of the wind turbine to the starting point A is OA, and the distance from the rotation center O of the wind turbine to any point C of the first guide section is OC, satisfying: OA≥OC. The first guide section includes an arc portion, and the distance from the rotation center O of the wind turbine to any point of the arc portion is equal.

2. The centrifugal fan according to claim 1, characterized in that, The helical surface includes a second guide section and a third guide section. The second guide section is located on the side of the first guide section away from point P, and the third guide section is located on the side of the second guide section away from the first guide section. The endpoint of the third guide section on the side away from the second guide section is the endpoint I of the helical surface. Along the direction away from point P, the distance from the rotation center O of the wind turbine to the second guide section gradually decreases, and the distance from the rotation center O of the wind turbine to the third guide section gradually increases.

3. The centrifugal fan according to claim 1, characterized in that, The helical surface includes a second guide section and a third guide section. The second guide section is located on the side of the first guide section away from point P, and the third guide section is located on the side of the second guide section away from the first guide section. The endpoint of the third guide section on the side away from the second guide section is the endpoint I of the helical surface. Along the direction away from point P, the distance from the rotation center O of the wind turbine to the second guide section gradually increases, and the distance from the rotation center O of the wind turbine to the third guide section gradually increases or remains unchanged.

4. The centrifugal fan according to claim 1, characterized in that, The spiral surface has points D and E, with an included angle ∠POD = 90°. Point E is located between points P and D, satisfying: OE ≤ OP, and / or OD ≤ OE.

5. The centrifugal fan according to claim 1, characterized in that, The spiral surface has points D, G, and H, with included angles ∠POD = 90° and ∠DOG = 90°. Point G is located on the side of point D away from point P. Along the direction from point D to point G, the distance from the rotation center O of the wind turbine to the spiral surface between points D and G gradually increases. Alternatively, point H is located between points D and G, satisfying: OH ≤ OD, and / or, OG ≤ OH.

6. The centrifugal fan according to claim 1, characterized in that, The first guide section includes a gradient section. Along the direction away from the point P, the distance from the rotation center O of the wind turbine to the gradient section gradually decreases, and the arc length of the gradient section is smaller than the arc length of the circular arc section.

7. The centrifugal fan according to claim 6, characterized in that, The gradient section is located on the side of the arc section closer to point P.

8. The centrifugal fan according to claim 1, characterized in that, The first guide section is entirely composed of the circular arc portion.

9. The centrifugal fan according to claim 1, characterized in that, The spiral surface includes a first expanding section, with the two ends of the first expanding section being the point P and the starting point A, respectively. Along the direction away from the point P, the distance from the rotation center O of the wind turbine to the first expanding section gradually increases.

10. The centrifugal fan according to claim 1, characterized in that, The spiral surface includes a second expanding section, which is located on the side of the first guide section away from point P. The distance from the rotation center O of the wind turbine to the second expanding section gradually increases in the direction away from point P.

11. The centrifugal fan according to any one of claims 1 to 10, characterized in that, Along the circumference of the helical surface, the extension path of the helical surface is a smooth and continuous curve.

12. A household appliance, characterized in that, include: The centrifugal fan according to any one of claims 1 to 11.

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