Radiator-Shroud Structure

Abstract

A shroud 15 attached to an air discharge side of a radiator 13 narrows toward a centrifugal-flow-type rotary fan 11 and forms a cylindrical shape. A surrounding portion 17 is provided so as to surround the rotary fan 11. A guide portion 23 extending in the centrifugal direction of the rotary fan 11 is provided at a circumferential edge portion of the surrounding portion 17. A cylindrical portion 19, which is smaller in diameter than the surrounding portion 17 is provided inside the surrounding portion 17, and an upper portion of the cylindrical portion 19 is fixed to the wall surface of the shroud 15. A lower portion of the cylindrical portion 19 is fixed by a fixing portion 21 having an inner diameter equal to the diameter of the cylindrical portion and an outer diameter equal to the diameter of the surrounding portion 17.

1 . A radiator-shroud structure comprising:
 a rotary fan which produces a centrifugal flow of air;   a radiator provided in the, vicinity of the rotary fan; and   a shroud for forming an air guide passage extending from the radiator toward the rotary fan, the radiator-shroud structure being characterized by comprising:   a surrounding portion which surrounds the outer circumference of the rotary fan at an one end of the shroud;   a cylindrical portion which is smaller in diameter than the surrounding portion; and   a fixing portion for fixing the cylindrical portion inside the surrounding portion such that one end of the cylindrical portion faces the rotary fan, wherein   the fixing portion is formed such that the fixing portion prevents passage of air outside the cylindrical portion within the shroud.   
     
     
         2 . A radiator-shroud structure according to  claim 1 , wherein the cylindrical portion is approximately equal in diameter to the rotary fan, and is disposed such that the cylindrical portion is juxtaposed with an outer circumferential portion of the rotary fan. 
     
     
         3 . A radiator-shroud structure according to  claim 1 , wherein the width of the cylindrical portion is set such that a circumferential edge portion of the cylindrical portion does not come into contact with the rotary fan and the distance between the circumferential edge portion of the cylindrical portion and the rotary fan can be decreased to a possible degree. 
     
     
         4 . A radiator-shroud structure according to  claim 1 , wherein the width of the cylindrical portion is set such that the distance between the circumferential edge portion of the cylindrical portion and the rotary fan becomes about 20 mm. 
     
     
         5 . A radiator-shroud structure according to  claim 1 , further comprising a guide portion extending radially outward from the circumferential edge of the surrounding portion. 
     
     
         6 . A radiator-shroud structure according to  claim 5 , wherein the guide portion has a width about 6% the diameter of the rotary fan. 
     
     
         7 . A radiator-shroud structure according to  claim 5 , wherein the cylindrical portion is approximately equal in diameter to the rotary fan, and is disposed such that the cylindrical portion is juxtaposed with an outer circumferential portion of the rotary fan.