Blower device

Abstract

A blower device includes a centrifugal fan that sucks air from one side of the blower device in an axial direction, and an air flow guide disposed between the centrifugal fan and the other side of the blower device in the axial direction. A first air flow from the centrifugal fan is bent toward the other side in the axial direction. A second air flow from the centrifugal fan is bent toward the other side in the axial direction, and then bent inward in the radial direction. A ratio of a pressure loss in the second air flow to a pressure loss in the first air flow before a downstream end of the air flow guide is smaller than a ratio of a pressure loss in the second air flow to a pressure loss in the first air flow before an upstream end of the air flow guide.

What is claimed is: 
     
         1 . A blower device comprising:
 a centrifugal blower including a centrifugal fan configured to rotate about an axis, suck air from one side of the blower device in an axial direction of the centrifugal fan, and blow the air outward in a radial direction of the centrifugal fan from a center located at the axis;   an air flow guide disposed between the centrifugal fan and the other side of the blower device in the axial direction; and   a casing accommodating the centrifugal fan and allowing the air to flow as an air flow toward the other side in the axial direction, wherein   the air flow from the centrifugal fan includes:
 a first air flow that is from the centrifugal fan, bent toward the other side in the axial direction, and then toward the other side in the axial direction; and 
 a second air flow that is from the centrifugal fan, bent toward the other side in the axial direction, and then bent inward in the radial direction, 
   a first pressure loss is a pressure loss generated in the first air flow between the centrifugal fan and an end of the air flow guide facing the other side in the axial direction,   a second pressure loss is a pressure loss generated in the second air flow between the centrifugal fan and the end of the air flow guide facing the other side in the axial direction,   a first pressure loss ratio is a divided value obtained by dividing the second pressure loss by the first pressure loss,   a third pressure loss is a pressure loss generated in the first air flow between the centrifugal fan and an end of the air flow guide facing the one side in the axial direction,   a fourth pressure loss is a pressure loss generated in the second air flow between the centrifugal fan and the end of the air flow guide facing in the axial direction,   a second pressure loss ratio is a divided value obtained by dividing the fourth pressure loss by the third pressure loss, and   the air flow guide is configured to make the first pressure loss ratio smaller than the second pressure loss ratio.   
     
     
         2 . The blower device according to  claim 1 , wherein the air flow guide is a filter configured to filter the first air flow and the second air flow to generate a pressure loss equal to the third pressure loss in each of the first air flow and the second air flow. 
     
     
         3 . The blower device according to  claim 2 , wherein the filter includes a filter medium formed in a film shape and configured to filter the first air flow and the second air flow, and
 the filter medium is formed in a wave shape having folds extending in a direction same as the radial direction.   
     
     
         4 . The blower device according to  claim 1 , wherein
 the centrifugal blower includes:
 a blower motor disposed between the centrifugal fan and the other side in the axial direction and configured to rotate the centrifugal fan; and 
 a blower motor cover disposed between the blower motor and the other side in the axial direction and covering the blower motor, and 
   the blower motor cover forms the air flow guide configured to guide the second air flow inward in the radial direction by a Coanda effect.   
     
     
         5 . The blower device according to  claim 1 , wherein the air flow guide is a plate member including a plate surface configured to generate a pressure loss in the first air flow by obstructing the first air flow toward the other side in the axial direction. 
     
     
         6 . The blower device according to  claim 1 , wherein the air flow guide is a plate member including a plate surface configured to guide the second air flow inward in the radial direction. 
     
     
         7 . The blower device according to  claim 1 , wherein the casing forms the air flow guide configured to generate a pressure loss in the first air flow by obstructing the first air flow toward the other side in the axial direction. 
     
     
         8 . The blower device according to  claim 1 , further comprising a cooling heat exchanger accommodated in the casing, disposed between the air flow guide and the other side in the axial direction, and configured to cool the first air flow and the second air flow that have passed through the air flow guide.