EP4273406A1

EP4273406A1 - Centrifugal fan and washing apparatus provided with same

Info

Publication number: EP4273406A1
Application number: EP21913912.8A
Authority: EP
Inventors: Zewang WANG; Can CUI; Fangzheng ZHOU; Wenfeng Jiang; Yongshun HOU
Original assignee: Qingdao Haier Drum Washing Machine Co Ltd; Haier Smart Home Co Ltd
Current assignee: Qingdao Haier Drum Washing Machine Co Ltd; Haier Smart Home Co Ltd
Priority date: 2021-01-04
Filing date: 2021-12-15
Publication date: 2023-11-08
Also published as: WO2022143171A1; EP4273406A4; CN114718888A

Abstract

A centrifugal fan (1) and a washing apparatus provided with same. The centrifugal fan (1) comprises: a volute (11), which is provided with a volute axial air-intake side wall (112), the volute axial air-intake side wall (112) being provided with a volute air inlet (111); and an impeller (12), which is configured to be rotatably arranged in the volute (11) and have an impeller axial air-intake side wall (122), wherein there is a first axial gap (14) between the impeller axial air-intake side wall (122) and the volute axial air-intake side wall (112); the impeller axial air-intake side wall (122) is provided with an impeller air inlet (121) which can be aligned with the volute air inlet (111); an outer annular protrusion (132), which extends outwards from the impeller axial air-intake side wall (122), is provided around the impeller air inlet (121), and an inner annular protrusion (131), which extends inwards from the volute axial air-intake side wall (112), is provided around the volute air inlet (111); the outer annular protrusion (132) and the inner annular protrusion (131) are configured to be opposite each other and are spaced apart by a second axial gap (15); and the second axial gap (15) is smaller than the first axial gap (14), so that the outer annular protrusion (132) and the inner annular protrusion (131) together constitute an air inner circulation blocking structure (13). Such a blocking structure can substantially eliminate the phenomenon of air inner circulation and increase the air output.

Description

FIELD OF THE INVENTION

The present disclosure relates to a washing apparatus, and specifically to a centrifugal fan and a washing apparatus having the same.

BACKGROUND OF THE INVENTION

Some existing washing apparatuses, such as drum-type heat pump washing-drying integrated machines, all have a drying system, which can provide a drying function for wet articles (such as clothing) that have been washed. The drying system typically includes a fan, a heater, and an evaporation device or another device that can cool hot and humid air. During a drying process, the fan blows hot air heated by the heater into a washing cylinder. The hot air is mixed with wet clothing in the washing cylinder to generate a hot and humid airflow. The hot and humid airflow is then discharged from the washing cylinder and enters a return air channel. In the return air channel, the hot and humid airflow is cooled through heat absorption of the evaporation device, and water vapor contained therein is condensed to become water droplets, thereby achieving the purpose of dehumidifying and cooling the airflow. The dehumidified airflow is sucked in again by the fan and undergoes a new cycle.
An air supply volume of the fan is a key factor that affects a drying efficiency of the washing apparatus. Currently, the commonly used form of the fan is a centrifugal fan. Such a centrifugal fan includes a volute and an impeller rotatably arranged in the volute. An air inlet is provided on an axial air inflow sidewall of the volute, and an air inlet is also provided on an axial air inflow sidewall of the impeller. In an assembled state of the volute and the impeller, the two air inlets are aligned with each other, and the axial air inflow sidewall of the volute is opposite to the axial air inflow sidewall of the impeller. However, a gap is left between the axial air inflow sidewall of the volute and the axial air inflow sidewall of the impeller to allow the impeller to rotate relative to the volute. Since the gap between the impeller and the volute is communicated with the air inlet and an air outlet of the impeller respectively, a potential wind circulation path is formed inside the centrifugal fan. When the centrifugal fan is working, a portion of the airflow will return to the air inlet of the impeller from the radial air outlet of the impeller along the wind circulation path and will be sucked in again by the impeller, as shown by a white arrow in FIG. 1. Therefore, the wind forms an ineffective circulation inside the centrifugal fan (which can be referred to as "internal wind circulation"). This internal wind circulation reduces an effective supply air volume of the centrifugal fan, thus further reducing the drying efficiency of the washing apparatus.
Accordingly, there is a need for a new technical solution in the art to solve the above problem.

SUMMARY OF THE INVENTION

In order to solve the above problem in the prior art, that is, to solve the technical problem of internal wind circulation in the centrifugal fan, the present disclosure provides a centrifugal fan, which includes: a volute, which has an axial air inflow sidewall of the volute, a volute air inlet being provided on the axial air inflow sidewall of the volute; and an impeller, which is configured to be rotatably arranged in the volute and has an axial air inflow sidewall of the impeller; a first axial gap is formed between the axial air inflow sidewall of the impeller and the axial air inflow sidewall of the volute, and an impeller air inlet that can be aligned with the volute air inlet is provided on the axial air inflow sidewall of the impeller; an outer annular protrusion extending outward from the axial air inflow sidewall of the impeller is arranged around the impeller air inlet, and an inner annular protrusion extending inward from the axial air inflow sidewall of the volute is arranged around the volute air inlet; the outer annular protrusion and the inner annular protrusion are arranged opposite to each other and spaced apart by a second axial gap, and the second axial gap is smaller than the first axial gap so that the outer annular protrusion and the inner annular protrusion together form an internal wind circulation blocking structure.
It can be understood by those skilled in the art that in the technical solution of the centrifugal fan of the present disclosure, an inner annular protrusion extending inward from the axial air inflow sidewall of the volute is arranged on the axial air inflow sidewall of the volute around the volute air inlet, and an outer annular protrusion extending outward from the axial air inflow sidewall of the impeller is arranged on the axial air inflow sidewall of the impeller around the impeller air inlet. The inner annular protrusion and the outer annular protrusion are opposite to each other and are spaced apart by a second axial gap, which is smaller than a first axial gap between the axial air inflow sidewall of the volute and the axial air inflow sidewall of the impeller. It is obvious that due to the blocking by the inner annular protrusion and the outer annular protrusion, as well as the narrowing of flow channel, a resistance to the wind flowing through the second axial gap is significantly larger than a resistance to the wind flowing through the first axial gap. Therefore, the outer annular protrusion and the inner annular protrusion together can play a role of blocking the wind from flowing into the impeller air inlet from the first axial gap. In other words, the outer annular protrusion and the inner annular protrusion together form an internal wind circulation blocking structure, which can substantially eliminate the phenomenon of internal wind circulation and therefore increase the effective supply air volume of the centrifugal fan.
In a preferred technical solution of the centrifugal fan described above, the outer annular protrusion includes a multi-stage outer annular step, and the inner annular protrusion includes a multi-stage inner annular step corresponding to the multi-stage outer annular step. The multi-stage steps extending axially on the fan form a flow channel with multiple substantially right angle turns, thereby achieving multi-stage blocking of the wind. Therefore, as the number of the stages of steps increases, the effect of the internal wind circulation blocking structure becomes better.
In a preferred technical solution of the centrifugal fan described above, inner annular grooves are formed between adjacent inner annular steps of the multi-stage inner annular step. By configuring these inner annular grooves, a total weight of the volute can be reduced, while also saving the amount of material used for the volute.
In a preferred technical solution of the centrifugal fan described above, the multi-stage outer annular step includes a three-stage outer annular step, and the multi-stage inner annular step includes a three-stage inner annular step. The three-stage outer annular step and the three-stage inner annular step together form three wind barriers that can block internal wind circulation, and the manufacturing process of the entire fan is also relatively simple.
In a preferred technical solution of the centrifugal fan described above, a multi-stage volute outer annular step extending outward from the axial air inflow sidewall of the volute is arranged around the volute air inlet, and each stage of the volute outer annular step and the corresponding stage of the inner annular step extend axially in opposite directions. The volute outer annular step is designed to reduce the weight of the volute, while also saving the amount of material used for the volute.
In a preferred technical solution of the centrifugal fan described above, the outer annular protrusion and the inner annular protrusion are configured to share a centerline with the volute air inlet and the impeller air inlet. The use of the same centerline makes the manufacturing of the centrifugal fan simpler and more convenient.
In a preferred technical solution of the centrifugal fan described above, the outer annular protrusion is positioned close to the impeller air inlet, and the inner annular protrusion is positioned close to the volute air inlet. Manufacturing the inner annular protrusion close to the volute air inlet and the outer annular protrusion close to the impeller air inlet substantially does not require changing the sizes of the volute and the impeller, but enables the centrifugal fan to have a function of blocking the internal wind circulation.
In a preferred technical solution of the centrifugal fan described above, the impeller is disc-shaped, a plurality of evenly spaced radial impeller air outlets are formed on an outer circumference of the impeller, and the radial impeller air outlets are communicated with each other to form an annular exhaust chamber inside the volute. The disc-shaped impeller is not only small in volume, but also is easy to produce.
In a preferred technical solution of the centrifugal fan described above, the volute further includes a motor mounting wall opposite to the axial air inflow sidewall of the volute, and the motor mounting wall is provided with a motor shaft hole and a plurality of motor mounting holes arranged circumferentially around the motor shaft hole. These motor mounting holes facilitate fixing the motor to the volute.
The present disclosure also provides a washing apparatus, which is provided with a drying system, and the drying system includes the centrifugal fan as described in any of the above. By using the centrifugal fan of the present disclosure, a drying air volume of the washing apparatus can be increased, thereby improving the drying efficiency of the washing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view showing an internal wind circulation path of a centrifugal fan of a washing apparatus in the prior art;
FIG. 2 is a partial cross-sectional schematic perspective view of an embodiment of the centrifugal fan of the present disclosure;
FIG. 3 is a partial cross-sectional schematic plan view of the embodiment of the centrifugal fan of the present disclosure;
FIG. 4 is a schematic perspective view of a part of an embodiment of a volute of the centrifugal fan of the present disclosure;
FIG. 5 is a schematic plan view of a part of the embodiment of the volute of the centrifugal fan of the present disclosure;
FIG. 6 is a schematic cross-sectional view of a part of the embodiment of the volute of the centrifugal fan of the present disclosure taken along E-E section line in FIG. 5;
FIG. 7 is a partially enlarged view of a portion F of a part of the embodiment of the volute of the centrifugal fan of the present disclosure shown in FIG. 6;
FIG. 8 is a schematic perspective view of an embodiment of an impeller of the centrifugal fan of the present disclosure;
FIG. 9 is a schematic front view of the embodiment of the impeller of the centrifugal fan of the present disclosure;
FIG. 10 is a right side view of the embodiment of the impeller of the centrifugal fan of the present disclosure; and
FIG. 11 is a partially enlarged view of a portion G of the embodiment of the impeller of the centrifugal fan of the present disclosure shown in FIG. 10.

List of reference signs:

1: centrifugal fan; 11: volute; 111: volute air inlet; 112: axial air inflow sidewall of the volute; 113: annular exhaust chamber; 114: motor mounting wall; 141: motor shaft hole; 142: circumferential end wall; 143: first circumferential rib wall; 144: second circumferential rib wall; 145: first radial rib; 146: second radial rib; 147: motor mounting hole; 148: third radial rib; 115: circumferential wall of the volute air inlet; 116: volute outer annular step; 116a: first-stage volute outer annular step; 116b: second-stage volute outer annular step; 116c: third-stage volute outer annular step; 117: reinforcing rib on the axial air inflow sidewall of the volute; 118: volute air outlet; 12: impeller; 121: impeller air inlet; 122: axial air inflow sidewall of the impeller; 123: blade; 124: blade bottom wall; 125: circumferential wall of the impeller air inlet; 126: central shaft hub; 127: central shaft hole; 128: outer circumference of the impeller; 129: radial impeller air outlet; 13: internal wind circulation blocking structure; 131: inner annular protrusion; 131a: first-stage inner annular step; 131b: second-stage inner annular step; 131c: third-stage inner annular step; 132: outer annular protrusion; 132a: first-stage outer annular step; 132b: second-stage outer annular step; 132c: third-stage outer annular step; 133: inner annular groove; 133a: first inner annular groove; 133b: second inner annular groove; 133c: third inner annular groove; 14: first axial gap; 15: second axial gap.

DETAILED DESCRIPTION OF THE EMBODIMENT(S) OF THE INVENTION

Preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principle of the present disclosure, and are not intended to limit the scope of protection of the present disclosure.
It should be noted that in the description of the present disclosure, terms indicating directional or positional relationships, such as "upper", "lower", "left", "right", "inner", "outer" and the like, are based on the directional or positional relationships shown in the accompanying drawings. They are only used for ease of description, and do not indicate or imply that the device or element must have a specific orientation, or be constructed or operated in a specific orientation; therefore, they should not be considered as limitations to the present disclosure. In addition, terms "first" and "second" are merely used for descriptive purpose, and should not be understood as indicating or implying relative importance.
In addition, it should also be noted that in the description of the present disclosure, unless otherwise clearly specified and defined, terms "mount", "arrange" and "connect" should be understood in a broad sense; for example, the connection may be a fixed connection, or may also be a detachable connection, or an integral connection; it may be a direct connection, or an indirect connection implemented through an intermediate medium, or it may be internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be interpreted according to specific situations.
In order to solve the technical problem of internal wind circulation of the centrifugal fan, the present disclosure provides a centrifugal fan 1. The centrifugal fan 1 includes: a volute 11, which has an axial air inflow sidewall 112 of the volute, a volute air inlet 111 being provided on the axial air inflow sidewall 112 of the volute; and an impeller 12, which is configured to be rotatably arranged in the volute 11 and has an axial air inflow sidewall 122 of the impeller; a first axial gap 14 is formed between the axial air inflow sidewall 122 of the impeller and the axial air inflow sidewall 112 of the volute, and an impeller air inlet 121 that can be aligned with the volute air inlet 111 is provided on the axial air inflow sidewall 122 of the impeller; an outer annular protrusion 132 extending outward from the axial air inflow sidewall 122 of the impeller is arranged around the impeller air inlet 121, and an inner annular protrusion 131 extending inward from the axial air inflow sidewall 112 of the volute is arranged around the volute air inlet 111; the outer annular protrusion 132 and the inner annular protrusion 131 are arranged opposite to each other and spaced apart by a second axial gap 15, and the second axial gap 15 is smaller than the first axial gap 14 so that the outer annular protrusion 132 and the inner annular protrusion 131 together form an internal wind circulation blocking structure 13. As shown in FIG. 3, an airflow b entering the first axial gap between the axial air inflow sidewall 112 of the volute and the axial air inflow sidewall 122 of the impeller is blocked when encountering the outer annular protrusion 132 and the inner annular protrusion 131 protruding into the first axial gap 14 from both sides, and a width D2 of the second axial gap 15 between the outer annular protrusion 132 and the inner annular protrusion 131 is significantly smaller than a width D1 of the first axial gap 14, so that a resistance to the airflow b flowing through the second axial gap 15 is significantly increased, ultimately forcing the airflow b to change its direction and flow toward an annular exhaust chamber 113 of the volute 11. Further, the second axial gap 15 may have multiple turns to further increase a resistance to the wind passing therethrough.
FIG. 2 is a partial cross-sectional schematic perspective view of an embodiment of the centrifugal fan of the present disclosure, and FIG. 3 is a partial cross-sectional schematic plan view of the embodiment of the centrifugal fan of the present disclosure. As shown in FIGS. 2 and 3, the centrifugal fan 1 of the present disclosure includes the volute 11 and the impeller 12. The impeller 12 is configured to be rotatably arranged in the volute 11. The centrifugal fan 1 further includes a motor (not shown in the drawings). The impeller 12 is fixedly connected with a drive shaft of the motor. When the centrifugal fan 1 is working, the drive shaft (not shown in the drawings) of the motor drives the impeller 12 to rotate inside the volute 11. Wind is drawn into the impeller 12 in a direction indicated by an arrow a (also referred to as an axial direction), then is discharged into the annular exhaust chamber 113 of the volute 11 in a radial flow direction r, and finally is blown out from a volute air outlet 118 (see FIG. 4). Appropriate gaps are required to be left between the impeller 12 and the volute 11 to allow the impeller 12 to rotate inside the volute 11 without being impeded. The gaps include axial gaps located on two opposite axial sides of the impeller 12 (in a direction of centerline c) and a radial gap located on an outer circumference of the impeller 12, such as the first axial gap 14 located on the air inflow side. The first axial gap 14 has a first axial width D1. Optionally, both the impeller 12 and the volute 11 can be made of appropriate injection molding materials. For example, the impeller 12 can be manufactured through one-time injection molding process. The manufactured impeller 12 is placed into a mold cavity used to manufacture the volute 11, and then the one-time injection molding process is used to not only manufacture the volute 11, but also assemble the volute 11 and the impeller 12 together. Alternatively, the impeller 12 and the volute 11 can also be made of other suitable metal materials and through other suitable processes.
FIG. 4 is a schematic perspective view of a part of an embodiment of the volute of the centrifugal fan of the present disclosure, FIG. 5 is a schematic plan view of a part of the embodiment of the volute of the centrifugal fan of the present disclosure, FIG. 6 is a schematic cross-sectional view of a part of the embodiment of the volute of the centrifugal fan of the present disclosure taken along E-E section line in FIG. 5, and FIG. 7 is a partially enlarged view of a portion F of a part of the embodiment of the volute of the centrifugal fan of the present disclosure shown in FIG. 6. As shown in FIGS. 2 to 6, the volute 11 includes the axial air inflow sidewall 112 of the volute and an opposite motor mounting wall 114. The axial air inflow sidewall 112 of the volute and the motor mounting wall 114 together enclose an impeller chamber (not labelled in the drawings) that can accommodate the impeller 12. The annular exhaust chamber 113 surrounding the impeller chamber is formed on a radial outer circumference of the impeller chamber. The annular exhaust chamber 113 is communicated with the impeller chamber to receive the airflow discharged from the impeller 12. As shown in FIGS. 2 and 3, in one or more embodiments, the annular exhaust chamber 113 has a substantially rectangular cross section, and four corners of the cross section are each rounded. Along the axial direction (i.e., the direction of the centerline c), a width of the cross section of the annular exhaust chamber 113 is larger than a width of the cross section of the impeller chamber. As shown in FIGS. 4 and 5, the volute air outlet 118 is provided in a circumferential direction of the annular exhaust chamber 113, and the annular exhaust chamber 113 is directly communicated with the volute air outlet 118 so as to blow wind outward from the volute air outlet 118.
As shown in FIGS. 2 and 3, in one or more embodiments, the motor mounting wall 114 of the volute 11 is a thin wall with a predetermined thickness. The predetermined thickness can be determined according to actual needs. A motor shaft hole 141 is provided in the center of the motor mounting wall 114 to allow the drive shaft of the motor to rotatably pass through. As shown in FIGS. 2 and 3, a connection slot (not labelled in the drawings) for accommodating a drive shaft end of the motor (i.e., an end from which the drive shaft extends outward) is provided on an outside surface of the motor mounting wall 114 (which is the right side surface based on the orientation shown in FIGS. 2 and 3). The connection slot is enclosed by a circumferential end wall 142. The circumferential end wall 142 extends outward perpendicularly by a first predetermined height from the outside surface of the motor mounting wall 114 by taking the motor shaft hole 141 as center. The first predetermined height can be determined according to actual needs. In an assembled state, the drive shaft end of the motor is inserted into the connection slot, and the drive shaft of the motor extends into the impeller chamber through the motor shaft hole 141.
As shown in FIGS. 2 and 3, in one or more embodiments, a first circumferential rib wall 143 and a second circumferential rib wall 144 are further provided on the outside surface of the motor mounting wall 114. The first circumferential rib wall 143 and the second circumferential rib wall 144 both surround the circumferential end wall 142 and are concentric with the circumferential end wall 142. The first circumferential rib wall 143 is located between the circumferential end wall 142 and the second circumferential rib wall 144, preferably in a middle position between the circumferential end wall 142 and the second circumferential rib wall 144. The first circumferential rib wall 143 and the second circumferential rib wall 144 extend outward perpendicularly by a second predetermined height and a third predetermined height respectively from the outside surface of the motor mounting wall 114. The second predetermined height and the third predetermined height can both be determined according to actual needs. In one or more embodiments, the first circumferential rib wall 143 is substantially flush with the circumferential end wall 142, while the second circumferential rib wall 144 extends outward beyond the first circumferential rib wall 143 and the circumferential end wall 142. As shown in FIG. 2, in one or more embodiments, a plurality of first radial ribs 145 are provided between the first circumferential rib wall 143 and the circumferential end wall 142. Each of the first radial ribs 145 extends radially from the circumferential end wall 142 to the first circumferential rib wall 143. Adjacent first radial ribs 145 are spaced apart by the same distance. Alternatively, uneven spacing can be formed between adjacent first radial ribs 145 according to actual needs. As shown in FIG. 2, in one or more embodiments, a plurality of second radial ribs 146 are provided between the first circumferential rib wall 143 and the second circumferential rib wall 144. Each of the second radial ribs 146 extends radially from the first circumferential rib wall 143 to the second circumferential rib wall 144. Adjacent second radial ribs 146 are spaced apart by the same distance. Alternatively, uneven spacing can be formed between adjacent second radial ribs 146 according to actual needs. The first circumferential rib wall 143, the second circumferential rib wall 144, the first radial ribs 145 and the second radial ribs 146 together can enhance the strength of the motor mounting wall 114.
As shown in FIG. 2, in one or more embodiments, a plurality of connection columns (not labelled in the drawings) spaced apart from each other are provided along the second circumferential rib wall 144. A motor connection hole 147 is provided on each of the connection columns. When the motor is assembled with the volute, the motor can be fixed to the volute 11 through these motor connection holes 147. Alternatively, the connection columns can be separated from the second circumferential rib wall 144, or the second circumferential rib wall 144 can be cancelled. As shown in FIG. 2, in one or more embodiments, a plurality of third radial ribs 148 are provided between the second circumferential rib wall 144 and the sidewall forming the annular exhaust chamber 113. Each of the third radial ribs 148 extends from the second circumferential rib wall 144 to the sidewall forming the annular exhaust chamber 113. Adjacent third radial ribs 148 are spaced apart by the same distance. Alternatively, uneven spacing can be formed between adjacent third radial ribs 148 according to actual needs. The third radial ribs 148 can further enhance the strength of the volute 11.
As shown in FIGS. 3 to 6, the volute air inlet 111 is arranged in the center of the axial air inflow sidewall 112 of the volute. The volute air inlet 111 is enclosed by a circumferential wall 115 of the volute air inlet around the centerline c. The axial air inflow sidewall 112 of the volute extends substantially radially from the circumferential wall 115 of the volute air inlet to the sidewall forming the annular exhaust chamber 113. As shown in FIGS. 6 and 7, an inner annular protrusion 131 extending inward (to the right based on the orientation shown in FIG. 6) from the axial air inflow sidewall 112 of the volute is arranged around the volute air inlet 111. In one or more embodiments, the inner annular protrusion 131 shares the centerline c with the volute air inlet 111, which facilitates manufacturing of the volute 11. Alternatively, according to actual needs, the center of the inner annular protrusion 131 can deviate from the center of the volute air inlet 111. As shown in FIG. 7, in one or more embodiments, the inner annular protrusion 131 is a three-stage inner annular step near the volute air inlet 111: a first-stage inner annular step 131a, a second-stage inner annular step 131b, and a third-stage inner annular step 131c. The first-stage inner annular step 131a is adjacent to and surrounds the circumferential wall 115 of the volute air inlet. In one or more embodiments, in order to save material and reduce the weight of the volute 11, a first inner annular groove 133a is formed between the first-stage inner annular step 131a and the circumferential wall 115 of the volute air inlet. On the inner side of the axial air inflow sidewall 112 of the volute, the circumferential wall 115 of the volute air inlet extends inward beyond the first-stage inner annular step 131a in the direction of the centerline c. The second-stage inner annular step 131b is adjacent to and surrounds the first-stage inner annular step 131a. On the inner side of the axial air inflow sidewall 112 of the volute, the second-stage inner annular step 131b extends inward beyond the first-stage inner annular step 131a in the direction of the centerline c. In one or more embodiments, in order to save material and reduce the weight of the volute 11, a second inner annular groove 133b is formed between the second-stage inner annular step 131b and the first-stage inner annular step 131a. The third-stage inner annular step 131c is adjacent to and surrounds the second-stage inner annular step 131b. On the inner side of the axial air inflow sidewall 112 of the volute, the third-stage inner annular step 131c extends inward beyond the second-stage inner annular step 131b in the direction of the centerline c. In one or more embodiments, in order to save material and reduce the weight of the volute 11, a third inner annular groove 133c is formed between the third-stage inner annular step 131c and the second-stage inner annular step 131b. The first inner annular groove 133a, the second inner annular groove 133b and the third inner annular groove 133c all belong to the inner annular groove 133c.
Alternatively, the inner annular protrusion 131 may be a one-stage, two-stage or more-than-three-stage step. Optionally, the inner annular grooves can be cancelled between adjacent steps. Alternatively, the inner annular protrusion 131 can be other suitable forms of protrusion such as ripples to block wind. Alternatively, the inner annular protrusion 131 can be positioned away from the volute air inlet 111, such as near a middle portion of the inner side of the axial air inflow sidewall 112 of the volute.
As shown in FIGS. 3 to 7, in one or more embodiments, a volute outer annular step 116 is arranged around the volute air inlet 111 on the outer side of the axial air inflow sidewall 112 of the volute, so as to maintain a relatively thin wall and a lighter weight of the axial air inflow sidewall 112 of the volute. As shown in FIG. 7, in one or more embodiments, the volute outer annular step 116 includes a first-stage volute outer annular step 116a, a second-stage volute outer annular step 116b, and a third-stage volute outer annular step 116c. The first-stage volute outer annular step 116a is adjacent to and surrounds the circumferential wall 115 of the volute air inlet. On the outer side of the axial air inflow sidewall 112 of the volute, the circumferential wall 115 of the volute air inlet extends outward beyond the first-stage volute outer annular step 116a in the direction of the centerline c. The first-stage volute outer annular step 116a and the first-stage inner annular step 131a are aligned with each other in the direction of the centerline c and extend in opposite directions. The second-stage volute outer annular step 116b is adjacent to and surrounds the first-stage volute outer annular step 116a. On the outer side of the axial air inflow sidewall 112 of the volute, the first-stage volute outer annular step 116a extends outward beyond the second-stage volute outer annular step 116b in the direction of the centerline c. The second-stage volute outer annular step 116b and the second-stage inner annular step 131b are aligned with each other in the direction of the centerline c and extend in opposite directions. The third-stage volute outer annular step 116c is adjacent to and surrounds the second-stage volute outer annular step 116b. On the outer side of the axial air inflow sidewall 112 of the volute, the second-stage volute outer annular step 116b extends outward beyond the third-stage volute outer annular step 116c in the direction of the centerline c. The third-stage volute outer annular step 116c and the third-stage inner annular step 131c are aligned with each other in the direction of the centerline c and extend in opposite directions.
Alternatively, the volute outer annular step 116 may be a one-stage, two-stage or more-than-three-stage step. Alternatively, the design of stepped protrusion can be cancelled on the outer side of the axial air inflow sidewall 112 of the volute. As shown in FIG. 4, in one or more embodiments, a plurality of reinforcing ribs 117 are provided on the outer side of the axial air inflow sidewall 112 of the volute. Each of the reinforcing ribs 117 extends radially outward from the outer circumference of the volute outer annular step 116 to the sidewall forming the annular exhaust chamber 113. Adjacent reinforcing ribs 117 have the same circumferential distance therebetween. Alternatively, according to actual needs, the circumferential distance between adjacent reinforcing ribs 117 may also be different.
FIG. 8 is a schematic perspective view of an embodiment of the impeller of the centrifugal fan of the present disclosure, FIG. 9 is a schematic front view of the embodiment of the impeller of the centrifugal fan of the present disclosure, FIG. 10 is a right side view of the embodiment of the impeller of the centrifugal fan of the present disclosure, and FIG. 11 is a partially enlarged view of a portion G of the embodiment of the impeller of the centrifugal fan of the present disclosure shown in FIG. 10. As shown in FIGS. 8 to 10, in one or more embodiments, the impeller 12 is a substantially disc-shaped impeller. The impeller 12 has the axial air inflow sidewall 122 of the impeller, a blade bottom wall 124, and a plurality of evenly spaced blades 123.
Referring to FIGS. 2 and 3, each of the blades 123 is formed into one piece with the blade bottom wall 124, and extends perpendicularly from the blade bottom wall 124 toward the axial air inflow sidewall 122 of the impeller in the direction of the centerline c. Each of the blades 123 is also formed into one piece with the axial air inflow sidewall 122 of the impeller on a portion near the outer circumference of the impeller 12. However, on a portion near the center of the impeller 12, a predetermined gap is formed between each of the blades 123 and the axial air inflow sidewall 122 of the impeller to allow wind to evenly enter all the gaps between adjacent blades. Referring to FIGS. 2 and 3, a central shaft hub 126 is provided in the center of the blade bottom wall 124. The central shaft hub 126 is a substantially cylindrical body around the centerline c. The central shaft hub 126 is formed into one piece with the blade bottom wall 124, and extends perpendicularly by a predetermined height from the blade bottom wall 124 toward the axial air inflow sidewall 122 of the impeller along the centerline c. The predetermined height should be lower than a maximum height of each blade 123. A central shaft hole 127 centered on the centerline c is formed in the center of the central shaft hub 126. The central shaft hole 127 penetrates through the entire central shaft hub 126. In the assembled state of the impeller 12 and the volute 11, the central shaft hole 127 is aligned with the motor shaft hole 141 on the motor mounting wall 114 and shares the centerline c with the motor shaft hole 141. Therefore, the drive shaft of the motor can extend from the motor shaft hole 141 into the center shaft hole 127 and thus be fixed together with the center shaft hub 126, so that the motor can drive the impeller 12 to rotate through the drive shaft. As shown in FIGS. 8 and 10, a plurality of radial impeller air outlets 129 are evenly distributed on the radial outer circumference 128 of the impeller 12. Each of the radial impeller air outlets 129 is communicated with the gap between the corresponding blades 123, so that the airflow sucked into the impeller 12 can be discharged from the radial impeller air outlets 129. In the assembled state of the impeller 12 and the volute 11, each of the radial impeller air outlets 129 is communicated with the annular exhaust chamber 113 of the volute 11.
As shown in FIGS. 8 and 9, the impeller air inlet 121 is arranged in the center of the axial air inflow sidewall 122 of the impeller. The impeller air inlet 121 is centered on the centerline c and is enclosed by a circumferential wall 125 of the impeller air inlet. In the assembled state of the impeller 12 and the volute 11, the impeller air inlet 121 is aligned with the volute air inlet 111 and shares the centerline c with the volute air inlet 111. The circumferential wall 125 of the impeller air inlet is sleeved over an inner end of the circumferential wall 115 of the volute air inlet that is opposite to the impeller 12, and a predetermined radial gap is formed between the circumferential wall 125 of the impeller air inlet and an outer circumference of the inner end to allow the impeller 12 to rotate relative to the volute 11. As shown in FIGS. 10 and 11, an outer annular protrusion 132 is arranged around the impeller air inlet 121 on the outer side of the axial air inflow sidewall 122 of the impeller. The outer annular protrusion 132 extends outward along the centerline c from the axial air inflow sidewall 122 of the impeller. In one or more embodiments, the outer annular protrusion 132 shares the centerline c with the impeller air inlet 121, which facilitates the manufacturing of the impeller 12. According to actual needs, the center of the outer annular protrusion 132 can deviate from the center of the impeller air inlet 121. In one or more embodiments, the outer annular protrusion 132 is positioned close to the impeller air inlet 121, and such an arrangement can eliminate the need to adjust the size of the entire impeller. In the assembled state of the impeller 12 and the volute 11, the outer annular protrusion 132 is opposite to the inner annular protrusion 131, and they are spaced apart by a second axial gap 15 that is smaller than the first axial gap 14. Therefore, the outer annular protrusion 132 and the inner annular protrusion 131 together can form an internal wind circulation blocking structure 13.
As shown in FIGS. 10 and 11, in one or more embodiments, the outer annular protrusion 132 includes a three-stage outer annular step: a first-stage outer annular step 132a, a second-stage outer annular step 132b, and a third-stage outer annular step 132c. The first-stage outer annular step 132a is adjacent to and surrounds the circumferential wall 125 of the impeller air inlet. Along the centerline c, the circumferential wall 125 of the impeller air inlet extends outward beyond the first-stage outer annular step 132a. The second-stage outer annular step 132b is adjacent to and surrounds the first-stage outer annular step 132a. Along the centerline c, the first-stage outer annular step 132a extends outward beyond the second-stage outer annular step 132b. The third-stage outer annular step 132c is adjacent to and surrounds the second-stage outer annular step 132b. Along the centerline c, the second-stage outer annular step 132b extends outward beyond the third-stage outer annular step 132c. Referring to FIGS. 2 and 3, in the assembled state of the impeller 12 and the volute 11, the first-stage outer annular step 132a of the impeller 12 is opposite to the first-stage inner annular step 131a of the volute 11, and a second axial gap 15 is formed therebetween; the second-stage outer annular step 132b is opposite to the second-stage inner annular step 131b, and a second axial gap 15 is formed therebetween; the third-stage outer annular step 132c is opposite to the third-stage inner annular step 131c, and a second axial gap 15 is formed therebetween. As shown in FIG. 3, the width D2 of the second axial gap 15 is significantly smaller than the width D1 of the first axial gap 14. Further, as shown in FIG. 3, since the inner and outer annular steps corresponding to the three stages are staggered from each other, the second axial gap 15 forms three substantially right angle turns. This design of the second axial gap 15 will significantly increase the resistance to the airflow flowing through the second axial gap 15, thus further enhancing the effect of blocking internal wind circulation.
Alternatively, the outer annular protrusion 132 may be a one-stage, two-stage or more-than-three-stage step, and matches with the inner annular protrusion 131. Alternatively, the outer annular protrusion 132 can be other suitable forms of protrusion such as ripples to block wind. Alternatively, the outer annular protrusion 132 can be positioned away from the impeller air inlet 121, such as near a middle portion of the outer side of the axial air inflow sidewall 122 of the impeller.
The present disclosure also relates to a washing apparatus (not shown in the drawings). The washing apparatus includes but is not limited to a drum washing machine and a pulsator washing machine. The washing apparatus is provided with a drying system (not shown in the drawings), and the washing apparatus includes any centrifugal fan 1 as described above. By using the centrifugal fan 1, the effective air supply volume of the centrifugal fan can be increased without increasing the power of the centrifugal fan, thereby improving the drying efficiency of the washing apparatus.
Hitherto, the technical solutions of the present disclosure have been described in connection with the preferred embodiments shown in the accompanying drawings, but it is easily understood by those skilled in the art that the scope of protection of the present disclosure is obviously not limited to these specific embodiments. Without departing from the principles of the present disclosure, those skilled in the art can combine technical features of different embodiments, or make equivalent changes or replacements to relevant technical features, and all the technical solutions after these changes or replacements will fall within the scope of protection of the present disclosure.

Claims

A centrifugal fan, comprising:
a volute, which has an axial air inflow sidewall of the volute, a volute air inlet being provided on the axial air inflow sidewall of the volute; and

an impeller, which is configured to be rotatably arranged in the volute and has an axial air inflow sidewall of the impeller, a first axial gap being formed between the axial air inflow sidewall of the impeller and the axial air inflow sidewall of the volute, and an impeller air inlet that can be aligned with the volute air inlet being provided on the axial air inflow sidewall of the impeller;

wherein an outer annular protrusion extending outward from the axial air inflow sidewall of the impeller is arranged around the impeller air inlet, and an inner annular protrusion extending inward from the axial air inflow sidewall of the volute is arranged around the volute air inlet; the outer annular protrusion and the inner annular protrusion are arranged opposite to each other and spaced apart by a second axial gap, and the second axial gap is smaller than the first axial gap so that the outer annular protrusion and the inner annular protrusion together form an internal wind circulation blocking structure.
The centrifugal fan according to claim 1, wherein the outer annular protrusion comprises a multi-stage outer annular step, and the inner annular protrusion comprises a multi-stage inner annular step corresponding to the multi-stage outer annular step.
The centrifugal fan according to claim 2, wherein inner annular grooves are formed between adjacent inner annular steps of the multi-stage inner annular step.
The centrifugal fan according to claim 2, wherein the multi-stage outer annular step comprises a three-stage outer annular step, and the multi-stage inner annular step comprises a three-stage inner annular step.
The centrifugal fan according to claim 2, wherein a multi-stage volute outer annular step extending outward from the axial air inflow sidewall of the volute is arranged around the volute air inlet, and each stage of the volute outer annular step and the corresponding stage of the inner annular step extend axially in opposite directions.
The centrifugal fan according to any one of claims 1 to 5, wherein the outer annular protrusion and the inner annular protrusion are configured to share a centerline with the volute air inlet and the impeller air inlet.
The centrifugal fan according to any one of claims 1 to 5, wherein the outer annular protrusion is positioned close to the impeller air inlet, and the inner annular protrusion is positioned close to the volute air inlet.
The centrifugal fan according to any one of claims 1 to 5, wherein the impeller is disc-shaped, a plurality of evenly spaced radial impeller air outlets are formed on an outer circumference of the impeller, and the radial impeller air outlets are communicated with each other to form an annular exhaust chamber inside the volute.
The centrifugal fan according to any one of claims 1 to 5, wherein the volute further comprises a motor mounting wall opposite to the axial air inflow sidewall of the volute, and the motor mounting wall is provided with a motor shaft hole and a plurality of motor mounting holes arranged circumferentially around the motor shaft hole.
A washing apparatus, which is provided with a drying system, and the drying system comprises the centrifugal fan according to any one of claims 1 to 9.