Fan Assembly and Vacuum Cleaner

Abstract

A vacuum cleaner and a fan assembly that includes a shell, a rotation shaft, a first impeller, a diffuser and a second impeller. The shell includes an air inlet and an air outlet in communication with each other. The rotation shaft is arranged in the shell and extends from the air inlet to the air outlet. The first impeller is arranged on the rotation shaft and located at a side of the air inlet. The diffuser is arranged in the shell and located at a side of the air outlet. The second impeller is arranged on the rotation shaft and located between the first impeller and the diffuser. The fan assembly may reduce working noise of the fan assembly while ensuring an air supply capacity of the fan assembly, and may reduce a radial size of the fan assembly, and may improve gas flow efficiency.

1 . A fan assembly, comprising:
 a shell, comprising an air inlet and an air outlet in communication with each other;   a rotation shaft, arranged in the shell and extending from the air inlet to the air outlet;   a first impeller, arranged on the rotation shaft and located at a side of the air inlet;   a diffuser, arranged in the shell and located at a side of the air outlet; and   a second impeller, arranged on the rotation shaft and located between the first impeller and the diffuser.   
     
     
         2 . The fan assembly of  claim 1 , further comprising:
 a flow guidance passage, provided with a first end and a second end in communication with an outlet end of the first impeller and an inlet end of the second impeller, respectively,   the flow guidance passage comprising:
 a diffusion passage, in communication with the outlet end of the first impeller, wherein a diameter of the diffusion passage gradually increases in a gas flow direction; and 
 a backflow passage, in communication with the diffusion passage and the inlet end of the second impeller. 
   
     
     
         3 . The fan assembly of  claim 2 , wherein the first impeller is a centrifugal impeller;
 the diffusion passage comprises at least one bend and is located at both sides of the first impeller, and the backflow passage is located between the first impeller and the second impeller.   
     
     
         4 . The fan assembly of  claim 2 , further comprising:
 a backflow structure, arranged in the shell and located between the first impeller and the second impeller,   the backflow structure comprising:
 a backflow disk, sleeved on the rotation shaft, and the flow guidance passage formed between the backflow disk and an inner wall of the shell; and 
 a guide blade, arranged on the backflow disk and at least partially located in the backflow passage. 
   
     
     
         5 . The fan assembly of  claim 4 , wherein on an axial section of the rotation shaft, a radial end surface of the backflow disk is a first arc line, a part of the inner wall of the shell forming the diffusion passage is a second arc line, and a distance between a first circle center of the first arc line and an axial end surface of the first impeller facing the backflow structure is less than a distance between a second circle center of the second arc line and an axial end surface of the first impeller facing the backflow structure. 
     
     
         6 . The fan assembly of  claim 5 , where a ratio of a distance between the first circle center and the second circle center to the distance between the first circle center and the axial end surface of the first impeller facing the backflow structure is greater than or equal to 2% and less than or equal to 7%. 
     
     
         7 . The fan assembly of  claim 4 , wherein on an axial section of the rotation shaft, a part of an end surface of the backflow disk forming the backflow passage is a first straight line, a part of the inner wall of the shell forming the backflow passage is a second straight line, the first straight line is parallel to the second straight line and extends in a radial direction of the rotation shaft. 
     
     
         8 . The fan assembly of  claim 1 , wherein the first impeller comprises:
 a first turntable, arranged on the rotation shaft;   a first blade, arranged on an end surface of the first turntable facing the air inlet; and   a first guidance hood, connected to the first blade, and the first blade located between the first turntable and the first guidance hood,   wherein a distance between an outer edge of the first guidance hood and an axis of the first impeller is greater than a distance between an outer edge of the first turntable and the axis of the first impeller.   
     
     
         9 . The fan assembly of  claim 1 , wherein the second impeller comprises:
 a second turntable, arranged on the rotation shaft;   a second blade, arranged on an end surface of the second turntable facing the first impeller; and   a second guidance hood, connected to the second blade, and the second blade located between the second turntable and the second guidance hood,   wherein on a cross section perpendicular to the rotation shaft, a distance between an outer edge of the second guidance hood and an axis of the second impeller is greater than a distance between an outer edge of the second turntable and the axis of the second impeller.   
     
     
         10 . The fan assembly of  claim 9 , wherein on an axial section passing through the rotation shaft, a straight line where an extension line of a radial edge of the second turntable is located intersects with an axis of the rotation shaft to form an included angle, and the included angle is located between the second turntable and the air outlet. 
     
     
         11 . The fan assembly of  claim 2 , further comprising:
 a flow guidance structure, arranged on the rotation shaft, a flow-past passage formed between the flow guidance structure and an inner wall of the shell, and the flow-past passage is in communication with an outlet end of the flow guidance passage and the inlet end of the second impeller,   wherein diameter of the flow guidance structure decreases first and then increases in an outflow direction of the flow-past passage.   
     
     
         12 . The fan assembly of  claim 1 , wherein the diffuser is an axial flow diffuser and comprises at least one group of diffusion blades distributed in an annular shape. 
     
     
         13 . The fan assembly of  claim 12 , wherein the diffuser comprises a plurality of groups of diffusion blades;
 a number of the diffusion blades in each group gradually increases in a gas flow direction; and/or   rotation angles of the diffusion blades in each group gradually decreases in the gas flow direction.   
     
     
         14 . The fan assembly of  claim 1 , wherein the shell comprises:
 a first mounting segment, in which the first impeller is located;   a second mounting segment, in which the second impeller and the diffuser are located; and   a transition segment, connected to the first mounting segment and the second mounting segment.   
     
     
         15 . The fan assembly of  claim 14 , wherein the transition segment is arranged to be recessed towards the rotation shaft, 
 the shell further comprises fins arranged on the transition segment and connected to the first mounting segment and the second mounting segment.   
     
     
         16 . The fan assembly of  claim 1 , wherein the rotation shaft is provided with a thread, and the fan assembly further comprises a nut mounted on the thread to fix the first impeller. 
     
     
         17 . A vacuum cleaner, comprising: the fan assembly of  claim 1 .