Fan and cleaner

Abstract

A fan includes an impeller rotated about the vertically extending central axis, a motor rotating the impeller, a motor housing housing the motor, and a fan casing disposed radially outside the motor housing to form a flow passage in a gap therebetween. A plurality of first stationary blades that axially extend and a second stationary blade that axially extends are disposed radially outside the motor housing. The first stationary blades are arranged in a circumferential direction. The second stationary blade is disposed between the first stationary blades adjacent to each other in the circumferential direction. An upper end of the second stationary blade is disposed further to a lower side than upper ends of the first stationary blades and further to an upper side than lower ends of the first stationary blades.

What is claimed is: 
     
         1 . A fan comprising:
 an impeller rotated about a vertically extending central axis;   a motor rotating the impeller;   a motor housing housing the motor;   a fan casing disposed radially outside the motor housing so as to form a flow passage in a gap therebetween;   a plurality of first stationary blades disposed radially outside the motor housing, the plurality of first stationary blades arranged in a circumferential direction, the plurality of first stationary blades extending in an axial direction; and   at least one second stationary blade disposed radially outside the motor housing, the at least one second stationary blade disposed between the first stationary blades adjacent to each other in the circumferential direction out of the plurality of first stationary blades, the at least one second stationary blade extending in the axial direction, the plurality of first stationary blades and the at least one second stationary blade being disposed such that an upper end of the at least one second stationary blade is disposed further to a lower side than upper ends of the plurality of first stationary blades and further to an upper side than a lower ends of the plurality of first stationary blades.   
     
     
         2 . The fan according to  claim 1 ,
 wherein a lower end of the at least one second stationary blade is disposed further to the lower side than the lower ends of the plurality of first stationary blades.   
     
     
         3 . The fan according to  claim 1 ,
 wherein, when seen in the axial direction, at least one of the plurality of first stationary blades is partially superposed on the at least one second stationary blade.   
     
     
         4 . The fan according to  claim 1 ,
 wherein at least part of the motor is in direct or indirect contact with the motor housing, and   wherein the plurality of first stationary blades and the at least one second stationary blade are formed of metal.   
     
     
         5 . The fan according to  claim 1 ,
 wherein the at least one second stationary blade includes a plurality of second stationary blades, and   wherein a number of the plurality of first stationary blades is equal to a number of the plurality of second stationary blades.   
     
     
         6 . The fan according to  claim 1 ,
 wherein, in the circumferential direction, a thickness of the at least one second stationary blade is smaller than a thickness of the plurality of first stationary blades.   
     
     
         7 . The fan according to  claim 6 ,
 wherein a first lower curved surface curved toward a leading side in a rotational direction of the impeller as the first lower curved surface extends downward is formed in a lower end portion of a first pressure surface of each of the plurality of first stationary blades,   wherein a second lower curved surface curved toward the leading side in the rotational direction of the impeller as the second lower curved surface extends downward is formed in a lower end portion of a second pressure surface of the at least one second stationary blade, and   wherein a radius of curvature of the second lower curved surface is larger than a radius of curvature of the first lower curved surface.   
     
     
         8 . The fan according to  claim 7 ,
 wherein the radius of curvature of the second lower curved surface is 1.8 to 2.5 times the radius of curvature of the first lower curved surface.   
     
     
         9 . The fan according to  claim 1 ,
 wherein the plurality of first stationary blades each include   a first stationary blade upper portion inclined toward the circumferential direction toward a trailing side in a rotational direction of the impeller as the first stationary blade upper portion extends from a lower side toward an upper side, and   a first stationary blade lower portion positioned further to the lower side than the first stationary blade upper portion in the axial direction, and   wherein the at least one second stationary blade includes   a second stationary blade upper portion inclined toward the circumferential direction toward the trailing side in the rotational direction of the impeller as the second stationary blade upper portion extends from the lower side toward the upper side, and   a second stationary blade lower portion positioned further to the lower side than the second stationary blade upper portion in the axial direction.   
     
     
         10 . The fan according to  claim 9 ,
 wherein the first stationary blade upper portion has a first curved surface curved further toward the trailing side than the first stationary blade lower portion in the rotational direction of the impeller, and   the second stationary blade upper portion has a second curved surface curved further toward the trailing side than the second stationary blade lower portion in the rotational direction of the impeller.   
     
     
         11 . The fan according to  claim 10 ,
 wherein a length in the circumferential direction between a trailing end of the first stationary blade in the rotational direction of the impeller and a leading end of a first pressure surface in the first stationary blade upper portion in the rotational direction of the impeller is larger than a length in the circumferential direction between a trailing end of the at least one second stationary blade in the rotational direction of the impeller and a leading end of a second pressure surface in the second stationary blade upper portion in the rotational direction of the impeller.   
     
     
         12 . The fan according to  claim 10 ,
 wherein a radius of curvature of the first pressure surface in the first curved surface is smaller than a radius of curvature of the second pressure surface in the second curved surface.   
     
     
         13 . The fan according to  claim 12 ,
 wherein the radius of curvature of the second pressure surface in the second curved surface is 1.8 to 2.2 times the radius of curvature of the first pressure surface in the first curved surface.   
     
     
         14 . The fan according to  claim 9 ,
 wherein the second stationary blade lower portion has an extended surface extending in the axial direction on a second pressure surface side at a position further to the lower side than the lower end of the first stationary blade.   
     
     
         15 . The fan according to  claim 14 ,
 wherein the first stationary blade lower portion has a first surface that extends in the axial direction on a first pressure surface side,   wherein the second stationary blade lower portion has a second surface that extends in the axial direction on the second pressure surface side, and   wherein, an axial length of the first surface is smaller than an axial length of the second surface.   
     
     
         16 . The fan according to  claim 1 ,
 wherein, in the circumferential direction, in a region where the plurality of first stationary blades and the at least one second stationary blade are superposed on one another, a center of the at least one second stationary blades is disposed at a center of a width between the first stationary blades adjacent to each other.   
     
     
         17 . The fan according to  claim 1 ,
 wherein, an axial length between the upper ends of the plurality of first stationary blades and the upper end of the at least one second stationary blade is smaller than a length of a gap in the circumferential direction between the upper ends of the first stationary blades adjacent to each other in the circumferential direction.   
     
     
         18 . The fan according to  claim 1 ,
 wherein an axial length of the at least one second stationary blade is larger than an axial length of the plurality of first stationary blades.   
     
     
         19 . The fan according to  claim 1 ,
 wherein the motor housing has a vent hole that penetrates therethrough in the radial direction so as to allow communication between the flow passage and an inside of the motor housing.   
     
     
         20 . A cleaner comprising:
 the fan according to  claim 1 .