Axial-flow fan

Abstract

An axial-flow fan according to the present disclosure can increase the amount of the airflow and simultaneously reduce the noise level. A plurality of stationary blades 11 A to 11 D are curved, in a convex manner, toward a rotating direction of an impeller. The plurality of stationary blades 11 A to 11 D are generally inclined so that discharge-side edge portions 11 d thereof are located more forward than suction-side edge portions 11 c thereof in the rotating direction. An inclination angle θ 4 of each of the plurality of stationary blades 11 A to 11 D in the vicinity of the external end portion 11 a is larger than the inclination angle θ 3 in the vicinity of the internal end portion 11 b . The inclination angle is gradually changed from the vicinity of the external end portion 11 a toward the vicinity of the internal end portion 11 b.

1 . An axial-flow fan comprising: 
 a fan housing including an air channel having an air discharge opening and an air suction opening,    an impeller having a plurality of blades and disposed inside the fan housing,    a rotor to which the impeller is fixed and which rotates about a shaft,    a stator disposed corresponding to the rotor,    a motor case including a bottom wall portion located at a side of the air discharge opening and a peripheral wall portion formed continuously with the bottom wall portion and extending toward the air suction opening, the stator being fixed to the bottom wall portion, and    a plurality of stationary blades disposed at intervals in a rotating direction of the rotor and located inside the air discharge opening of the air channel, each of the plurality of stationary blades connecting the motor case and the fan housing,    each of the plurality of stationary blades having an external end portion connected to an inner wall portion of the fan housing, an internal end portion connected to the peripheral wall portion of the motor case, a discharge-side edge portion formed between the external end portion and the internal end portion and located at a side of the air discharge opening, and a suction-side edge portion formed between the external end portion and the internal end portion and located at a side of the air suction opening,    each of the plurality of stationary blades being curved, in a convex manner, toward the rotating direction of the rotor,    all or most of stationary blades in the plurality of stationary blades being generally inclined so that the discharge-side edge portion of the stationary blade is located more forward than the suction-side edge portion thereof in the rotating direction,    wherein an inclination angle for all or most of the stationary blades in the vicinity of the external end portions thereof are larger than the inclination angle for all or most of the stationary blades in the vicinity of the internal end portions thereof, and the inclination angle is gradually changed from the vicinity of the external end portion toward the vicinity of the internal end portion; and    the inclination angle is defined as an angle between a virtual plane along the air discharge opening and a virtual line which passes through a first intersection where an orthogonal virtual plane, which is defined as being orthogonal to the virtual plane and also orthogonal to the discharge-side edge portion and the suction-side edge portion, intersects with the discharge-side edge portion, and also passes through a second intersection where the orthogonal virtual plane intersects with the suction-side edge portion.    
   
   
       2 . The axial-flow fan according to  claim 1 , wherein the air channel has a cross-sectional shape, as taken in a direction where an axial line is a perpendicular line, which becomes larger toward the air discharge opening in an area from where the impeller exists to where the air discharge opening is located.  
   
   
       3 . The axial-flow fan according to  claim 2 , wherein the inclination angle in the vicinity of the external end portion is within a range of 50° to 60°, and the inclination angle in the vicinity of the internal end portion is within a range of 45° to 55°.  
   
   
       4 . The axial-flow fan according to  claim 1 , wherein one stationary blade among the plurality of stationary blades has a structure which receives therein a plurality of lead wires for supplying electric power to the stator, and the stationary blades other than the one stationary blade are the most of the plurality of stationary blades.  
   
   
       5 . The axial-flow fan according to  claim 1 , wherein an outer surface of the bottom wall portion of the motor case is located closer to the air suction opening than the discharge-side edge portions of all or most of the plurality of the stationary blades are located.  
   
   
       6 . The axial-flow fan according to  claim 5 , wherein the outer surface of the bottom wall portion of the motor case is composed of a flat bottom surface and an outer peripheral surface portion continuous with the flat bottom surface, and the outer peripheral surface portion is gradually curved from the bottom surface toward an outer peripheral surface of the peripheral wall portion.  
   
   
       7 . The axial-flow fan according to  claim 4 , wherein all or most of the plurality of stationary blades each include an extended portion extending on the bottom wall portion of the motor case, and the extended portion has a guide surface for guiding a part of air flowing along the stationary blades toward the bottom surface of the bottom wall portion.  
   
   
       8 . The axial-flow fan according to  claim 7 , wherein the extended portion further has an extended guide surface formed continuously with the guide surface and extending toward the rotating direction.  
   
   
       9 . The axial-flow fan according to  claim 5 , wherein all or most of the plurality of stationary blades each include an extended portion extending on the bottom wall portion of the motor case, and the extended portion has a guide surface for guiding a part of air flowing along the stationary blades toward the bottom surface of the bottom wall portion.