Air conditioner including indoor unit

Abstract

An indoor unit for an air conditioner including a centrifugal fan. The centrifugal fan includes a main plate connectable to a rotation shaft of a motor, a plurality of blades, with one respective end to be bonded to the main plate and arrangeable at equal intervals from each other along a circumferential direction, a shroud, to be bonded to another respective end of the plurality of blades, to face the main plate, and a bell mouth arrangeable inside the shroud. An annular member arrangeable on an outer circumferential portion of the bell mouth with an inlet portion at the gap between the shroud and the bell mouth. The annular member including an annular flat plate portion spaced apart from and face the inlet portion, and a protrusion formed on an outer circumferential portion of a surface of the annular flat plate portion facing the shroud and being curved.

1 . An air conditioner including an indoor unit, the indoor unit comprising:
 a centrifugal fan to suck in air through an air intake port and discharge the air through an air discharge port; and   a heat exchanger to exchange heat with an air flow generated by the centrifugal fan,   wherein the centrifugal fan comprises:
 a main plate connectable to a rotation shaft of a motor; 
 a plurality of blades, with one respective end to be bonded to the main plate, so that while the one respective end of the plurality of blades is bonded to the main plate, the plurality of blades are arranged at equal intervals from each other along a circumferential direction; 
 a shroud, having an annular shape with an opening at a center thereof, to be bonded to another respective end of the plurality of blades, the shroud to face the main plate; 
 a bell mouth arrangeable inside the shroud to have a gap from the shroud to allow a recirculating flow of the air sucked through the air intake port and passed through the opening of the shroud to pass through the gap, the bell mouth having an inner diameter gradually increasing toward an upstream side of the recirculating flow; and 
 an annular member arrangeable at an outer circumferential portion of the bell mouth to be spaced apart from an inlet portion at the gap between the shroud and the bell mouth on the upstream side of the recirculating flow along a rotation axis direction of the shroud, and 
 the annular member comprises:
 an annular flat plate portion spaced apart from an upstream end of the inlet portion and facing the upstream end of the inlet portion; and 
 a protrusion formed on an outer circumferential portion of a surface of the annular flat plate portion facing the shroud, the protrusion having an outer surface that is curved. 
 
   
     
     
         2 . The air conditioner of  claim 1 , wherein a cross-sectional shape of the outer surface of the protrusion is partially circular. 
     
     
         3 . The air conditioner of  claim 1 , wherein the protrusion is farther than the inlet portion along a radial direction of the shroud. 
     
     
         4 . The air conditioner of  claim 1 , wherein the annular flat plate portion has a portion closest to the upstream end of the inlet portion, and
 the protrusion is further spaced apart from the upstream end of the inlet portion than the portion of the annular flat plate portion closest to the upstream end of the inlet portion.   
     
     
         5 . The air conditioner of  claim 1 , wherein a communication flow path for air flow along the rotation axis direction of the shroud is formed between the annular member and the bell mouth. 
     
     
         6 . The air conditioner of  claim 5 , wherein the communication flow path has an enlarged portion having a cross-sectional area that gradually increases from an inlet side toward an outlet side. 
     
     
         7 . The air conditioner of  claim 6 , wherein the communication flow path has a reduced portion, on the inlet side of the enlarged portion, having a flow path cross-sectional area that gradually decreases. 
     
     
         8 . The air conditioner of  claim 5 , wherein the communication flow path is formed between an inner circumferential surface of the annular flat plate portion and an outer circumferential surface of the bell mouth. 
     
     
         9 . The air conditioner of  claim 5 , wherein a width of the communication flow path is less than the gap between the shroud and the bell mouth. 
     
     
         10 . An air conditioner including an indoor unit, the indoor unit comprising:
 a centrifugal fan to suck in air through an air intake port and discharge the air through an air discharge port; and   a heat exchanger to exchange heat with an air flow generated by the centrifugal fan,   wherein the centrifugal fan comprises:
 a main plate connectable to a rotation shaft of a motor; 
 a plurality of blades, with one respective end to be bonded to the main plate, so that while the one respective end of the plurality of blades is bonded to the main plate, the plurality of blades are arranged at equal intervals from each other in a circumferential direction; 
 a shroud, having an annular shape with an opening at a center thereof, to be bonded to another respective end of the plurality of blades, with an opening at a center, the shroud to face the main plate; 
 a bell mouth, inside the shroud and spaced apart from the shroud to allow air flow, having an inner diameter that gradually increases toward an upstream side of the air flow; and 
 an annular member arrangeable at an outer circumferential portion of the bell mouth with a gap from an inlet portion at the gap between the shroud and the bell mouth on an upstream side of the shroud along a rotation axis direction of the shroud, and 
   a communication flow path, to allow flow of air along the rotation axis direction of the shroud, is formed between the annular member and the bell mouth.   
     
     
         11 . The air conditioner of  claim 10 , wherein the communication flow path has an enlarged portion having a cross-sectional area that gradually increases from an inlet side toward an outlet side. 
     
     
         12 . The air conditioner of  claim 11 , wherein the communication flow path has, on the inlet side of the enlarged portion, a reduced portion having a flow path cross-sectional area that gradually decreases. 
     
     
         13 . The air conditioner of  claim 10 , wherein the communication flow path is formed between the annular member and an outer circumferential surface of the bell mouth. 
     
     
         14 . The air conditioner of  claim 10 , wherein a width of the communication flow path is less than a gap formed between the shroud and the bell mouth such that a recirculating flow passes through the gap. 
     
     
         15 . The air conditioner of  claim 10 , wherein the communication flow path has, on an inlet side of an enlarged portion, an enlarged portion having a cross-sectional area that gradually increases from an inlet side toward an outlet side, and a reduced portion having a flow path cross-sectional area that gradually decreases.