Air blower

Abstract

An air blower capable of suppressing movement of an impeller in a thrust direction is provided. A first case includes a first air inlet and a first air outlet. A second case includes a second air inlet communicating with the first air inlet and a second air outlet communicating with the first air outlet. An impeller is provided inside the second case. A motor rotates the impeller. A first flow channel is provided between the motor and the second case on the opposite side of the first air inlet and the second air inlet relatively to the impeller. A second flow channel is provided between the first case and the second case and communicates with the first flow channel, the first air inlet, and the second air inlet.

What is claimed is: 
     
         1 . An air blower comprising:
 a first case including a first air inlet and a first air outlet;   a second case provided inside the first case and including a second air inlet communicating with the first air inlet and a second air outlet communicating with the first air outlet;   an impeller being provided inside the second case, a rotational axis of which is made coincident with a central axis of each of the first air inlet and the second air inlet, and serving as a centrifugal fan;   a motor being provided inside the second case and to rotate the impeller;   a first flow channel provided between the motor and the second case on the opposite side of the first air inlet of the impeller and the second air inlet; and   a second flow channel provided between the first case and the second case and communicating with the first flow channel, the first air inlet, and the second air inlet.   
     
     
         2 . The air blower of  claim 1 , wherein
 the first air inlet of the first case includes a first side surface parallel to the central axis, and the second air inlet of the second case includes a second side surface parallel to the first side surface.   
     
     
         3 . The air blower of  claim 2 , further comprising a second flow channel provided between a first surface of the impeller on the first and second air inlets side and a second surface of the second case opposed to the first surface, and between the second air inlet of the second case and a surface of the impeller opposed to the second air inlet, and communicating with the first air inlet and the second air inlet. 
     
     
         4 . The air blower of  claim 3 , further comprising:
 a base configured to cover a bottom portion of the first case; and   a ring-shaped sealing member provided between the first case and the base.   
     
     
         5 . An air blower comprising:
 a first case including a first air inlet and a first air outlet;   a second case provided inside the first case and including a second air inlet communicating with the first air inlet and a second air outlet communicating with the first air outlet;   an impeller being provided inside the second case, a rotational axis of which is made coincident with a central axis of each of the first air inlet and the second air inlet, and serving as a centrifugal fan; and   a motor being provided inside the second case and configured to rotate the impeller, wherein   the first air inlet and the second air inlet are arranged concentric with each other, and two side surfaces between the first air inlet and the second air inlet are parallel to the rotational axis and each form a first flow channel which guides air between the first case and the second case to the first air inlet and the second air inlet.   
     
     
         6 . The air blower of  claim 5 , wherein
 the second case includes a ring-shaped concave portion provided around the second air inlet and in a surface thereof opposed to the impeller,   the impeller includes a ring-shaped protruding portion on the first surface thereof on the first and second air inlets side, the ring-shaped protruding portion being arranged inside the concave portion, and   two side surfaces between the concave portion and the protruding portion and parallel to the rotational axis each constitute a second flow channel which guides air on the surface corresponding to the first air inlet and the second air inlet of the impeller to the first air outlet and the second air outlet.   
     
     
         7 . The air blower of  claim 6 , wherein
 a gap of the first flow channel in a direction intersecting the rotational axis at right angles is less than a gap between the first case and the second case, and forms a first choke.   
     
     
         8 . The air blower of  claim 7 , wherein
 a gap of the second flow channel in a direction intersecting the rotational axis at right angles is less than a gap between the surface of the impeller corresponding to the first air inlet and the second air inlet and the second case, and forms a second choke.